Diseases of the Eye


Basal Cell Carcinoma

Basal Cell Carcinoma

Basal cell carcinoma is a type of skin cancer that occurs most commonly on the face or neck, often near an eyelid or on the nose. The tumor cells are thought to originate from the basal, or innermost, layer of the skin.

Basal cell carcinoma is one of the most common type of skin cancer. Fair-skinned people over age 50 are most commonly affected; it is rare among those with dark skin. The incidence increases significantly with sun exposure. Those who work outdoors or live in sunny climates or areas with high sun exposure are at greater risk.

The ultraviolet radiation in sunlight is believed to be the cause in most cases. People with dark complexions have more melanin in their skin and are able to absorb higher amounts of the damaging ultraviolet rays. Since those with fair skin have less melanin, they are less able to withstand the effects of UV exposure.

bcc

Signs and Symptoms

  • Typically appears on the eyelid (the lower lid is more common than the upper)
  • Begins as a small, raised growth
  • Classic appearance is a nodule with a pitted center
  • Tumor edges may have a "pearly" appearance
  • Does not cause discomfort, but if advanced, may cause lid to turn in or out

Detection and Diagnosis

If left untreated, the growth may gradually invade the surrounding tissue. Fortunately, basal cell carcinomas rarely metastasize (spread to other parts of the body). Diagnosis is made by microscopic examination of the tumor cells.


Treatment

Basal cell carcinoma can be removed surgically or with radiation. As with any type of cancer, early detection is important. Consult with an eye care practitioner or dermatologist about any suspicious growth appearing on the eyelids or skin.


Prevention

Individuals at risk, especially the fair-skinned, should avoid overexposure to sunlight. Wear sunglasses to protect the delicate skin around the eyelids from UV light. Protective clothing, headgear, and sunscreen are also advisable when spending time outdoors.

 

 

Corneal Ulcer

corneal ulcer forms when the surface of the cornea is damaged or compromised. Ulcers may be sterile (no infecting organisms) or infectious. The term infiltrate is also commonly used along with ulcer. Infiltrate refers to an immune response causing an accumulation of cells or fluid in an area of the body where they don't normally belong.

Whether or not an ulcer is infectious is an important distinction for the physician to make and determines the course of treatment. Bacterial ulcers tend to be extremely painful and are typically associated with a break in the epithelium, the superficial layer of the cornea. In some cases, the inflammatory response involves the anterior chamber along with the cornea. Certain types of bacteria, such as Pseudomonas, are extremely aggressive and can cause severe damage and even blindness within 24-48 hours if left untreated.

Sterile infiltrates on the other hand, cause little if any pain. They are often found near the peripheral edge of the cornea and are not necessarily accompanied by a break in the epithelial layer of the cornea.

There are many causes of corneal ulcers. Contact lens wearers (especially soft) have an increased risk of ulcers if they do not adhere to strict regimens for the cleaning, handling, and disinfection of their lenses and cases. Soft contact lenses are designed to have very high water content and can easily absorb bacteria and infecting organisms if not cared for properly. Pseudomonas is a common cause of corneal ulcer seen in those who wear contact lenses.

Bacterial ulcers may be associated with diseases that compromise the corneal surface, creating a window of opportunity for organisms to infect the cornea. Patients with severely dry eyes, difficulty blinking, or who are unable to care for themselves, are also at risk. Other causes of ulcers include: herpes simplex viral infections, inflammatory diseases, corneal abrasions or injuries, and other systemic diseases.


Signs and Symptoms

The symptoms associated with corneal ulcers depend on whether they are infectious or sterile, as well as the aggressiveness of the infecting organism.

  • Red eye

  • Severe pain (not in all cases)

  • Tearing

  • Discharge

  • White spot on the cornea, that depending on the severity of the ulcer, may not be visible with the naked eye

  • Light sensitivity


Detection and Diagnosis

Corneal ulcers are diagnosed with a careful examination using a slit lamp microscope. Special types of eye drops containing dye such as fluorescein may be instilled to highlight the ulcer, making it easier to detect.

If an infectious organism is suspected, the eye care practitioner may order a culture. After numbing the eye with topical anaesthetic eye drops, cells are gently scraped from the corneal surface and tested to determine the infecting organism.


Treatment

The course of treatment depends on whether the ulcer is sterile or infectious. Bacterial ulcers require aggressive treatment. In some cases, antibacterial eye drops are used every 15 minutes. Steroid medications are avoided in cases of infectious ulcers. Some patients with severe ulcers may require hospitalization for IV antibiotics and around-the-clock therapy. Sterile ulcers are typically treated by reducing the eye's inflammatory response with steroid drops, anti-inflammatory drops, and antibiotics.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital

 

Dacryocystitis

Dacryocystitis is an infection of the tear sac that lies between the inner corner of the eyelids and the nose. It usually results from blockage of the duct that carries tears from the tear sac to the nose. The blocked duct harbours bacteria and becomes infected. Dacryocystitis may be acute (sudden onset) or chronic (frequently recurs). It may be related to a malformation of the tear duct, injury, eye infection, or trauma.

This problem is most common in infants because their tear ducts are often underdeveloped and clog easily. Babies often have recurrent episodes of infection; however, in most cases, the problem resolves as the child grows. In adults, the infection may originate from an injury or inflammation of the nasal passages. In many cases, however, the cause is unknown.


Signs and Symptoms

  • Generally affects one eye

  • Excessive tearing

  • Tenderness, redness, and swelling

  • Discharge

  • Red, inflamed bump on the inner corner of the lower lid


Detection and Diagnosis

During the examination, the eye care practitioner will determine the extent of the blockage. Cultures may be taken of the discharge to identify the type of infection. The eye care practitioner will also determine whether the infection has affected the eye.


Treatment

The treatment for dacryocystitis is dependent on the person's age, whether the problem is chronic or acute, and the cause of the infection.

Infants are usually treated first by gently massaging the area between the eye and nose to help open the obstruction along with antibiotic drops or ointments for the infection. Surgery may be necessary to clear the obstruction if medical treatment is not effective and the problem persists over several months.

Before surgery, the eye care practitioner may treat the child with antibiotics to make sure the infection is cleared. The operation is performed under general anaesthesia. The tear duct is gently probed to open the passage.

For adults, the eye care practitioner may clear the obstruction by irrigating the tear duct with saline. Surgery is sometimes necessary for adults if irrigation, or antibiotics fail to resolve the infection or if the infection becomes chronic. In these cases, dacryocystorhinostomy (DCR) is performed under general anaesthesia to create a new passage for the tear flow.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Epi-Retinal Membrane

(Macular Pucker)


Epi-retinal membrane (ERM) or macular pucker is a cellophane-like membrane that forms over the macula. It is typically a slow-progressing problem that affects the central vision by causing blur and distortion. As it progresses, the traction of the membrane on the macula may cause swelling.

ERM is seen most often in people over 75 years of age. It usually occurs for unknown reasons, but may be associated with certain eye problems such as: diabetic retinopathy, posterior vitreous detachment, retinal detachment, trauma, and many others.


Signs and Symptoms

  • Blurred vision
  • Double vision that is noticeable even with one eye covered
  • Distorted vision (straight lines may appear bent or wavy)

Detection and Diagnosis

The eye care practitioner is able to detect ERM with ophthalmoscopy during an examination of the retina. It has a glistening, cellophane-like appearance. The affect of ERM on the patient's central vision is assessed with a visual acuity test and the Amsler Grid. If the eye care practitioner suspects macular swelling, he may order fluorescein angiography.


Treatment

A procedure called a membrane peel is performed when vision has deteriorated to the point that it is impairing the patient's lifestyle. Most vitreo-retinal surgeons recommend waiting for treatment until vision has decreased to the point that the risk of the procedure justifies the improvement.

The membrane peel is performed under local anaesthesia in an operating theatre. After making tiny incisions the membrane peel is often done in conjunction with a procedure called a vitrectomy.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Foreign Body

Anyone who has felt as if there was a grain of sand in his or her eye has probably had a foreign body. Foreign bodies might be superficial, or in more serious injuries, they may penetrate the eye. Fortunately, the cornea has such an incredible reflex tearing system that most superficial foreign bodies are naturally flushed out with our natural tears. But if the object is more deeply embedded, medical attention is required.


Signs and Symptoms

The symptoms of a foreign body may range from irritation to intense, excruciating pain. This is dependent on the location, material, and type of injury.

In rare situations where an object penetrates the eye, there may be few or no symptoms. If you have no symptoms, but suspect an object may have penetrated your eye, it's always best to seek medical attention. The entry point of an intraocular foreign body is sometimes nearly invisible. Depending on their location, foreign bodies inside the eye may or may not cause pain or decreased vision.

foreign body
  • Mild to extreme irritation
  • Scratching
  • Burning
  • Soreness
  • Intense pain
  • Redness
  • Tearing
  • Light sensitivity
  • Decreased vision
  • Difficulty opening the eye

Detection and Diagnosis

The evaluation includes vision testing along with careful examination of the surface of the eye with a slit lamp microscope. When a superficial foreign body is suspected, the upper lid should be gently turned up to check underneath for trapped particles. If the foreign body is difficult to see even with a microscope, the eye care practitioner may instill a drop of fluorescein dye to highlight the area.

An examination inside the eye with ophthalmoscopy may also be indicated depending on the severity of the injury.


Treatment

If a foreign object becomes embedded within the cornea, conjunctiva, or sclera, a medical professional must remove it.Attempting to remove it yourself is dangerous and could result in a permanent scar that could affect your vision.

Superficial foreign bodies are usually treated in the office. After numbing the eye with topical anaesthetic, the particle is carefully removed using a microscope. Afterward, antibiotic medications are generally prescribed to prevent infection. In some cases, foreign bodies become trapped underneath the eyelid. It is extremely important to examine under the eyelid for any remnant particles.

Intraocular foreign bodies typically must be removed in the operating theatre using a microscope and special instruments designed for working inside the eye. These injuries are often vision threatening and should be treated quickly.

Wearing appropriate safety glasses is the best way to prevent this type of injury. Protecting the eyes is especially important when working with machinery that could cause chips of wood or metal to splinter, as well as lawn equipment such as hedge and line trimmers.

If a particle of wood, glass, metal or any other foreign substance becomes trapped in your eye, here are some tips:

  1. Do not touch or rub your eye! This can embed the object more deeply, making it more difficult to remove.
  2. Keep your eye closed as much as possible. Blinking only increases the irritation.
  3. Do not try to remove the object yourself. This is very dangerous and may make the problem worse.
  4. Seek professional help immediately.

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

 

Ocular Histoplasmosis Syndrome

Histoplasmosis is caused by a fungus commonly found in certain dust and soil. It affects men and women equally.

histoplasmosisHistoplasmosis is contracted by inhaling dust that carries the fungal spores. Its effect on the body can vary widely in severity from one person to another. Many carriers have no symptoms at all, but those with mild exposure may experience flu-like symptoms and mild respiratory infections. Histoplasmosis is more likely to become a serious problem in people who already have a weakened immune system.

The fungus may affect the eye by causing small areas of inflammation and scarring of the retina. These are called "histo spots" and may be found in both eyes. Their effect on vision depends on the location of the scars. Scarring in the peripheral area of the retina may have little or no impact on vision, while a central scar affecting the macula may cause a prominent blind spot.

Most people with histo spots in the retina are totally unaware of their presence unless the central vision is affected. Studies indicate that only about 5% of those with histo spots are at risk of losing vision. Scientists have been unable find a link between the patients with minor histo spots and those who develop a severe loss of their central vision.


Signs and Symptoms

Many patients with histo spots in their eyes have no symptoms. Others may experience the following:

  • Distorted vision
  • Blind spots
  • Scars in the retina, ranging in severity

Detection and Diagnosis

Ocular histoplasmosis is detected with a dilated pupil examination of the retina using ophthalmoscopy. It is usually diagnosed based on its distinctive appearance and characteristics.


Treatment

Ocular histoplasmosis usually requires no treatment except when abnormal blood vessels develop in the central retina. For these patients, laser treatment may be necessary. In some cases, surgical removal of the tiny, abnormal vessels has been successful.

Regular eye examinations and routine use of an Amsler Grid to monitor central vision is recommended for anyone with histo spots.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

 

Posterior Capsule Opacification

The lens capsule is the thin, elastic-like bag that holds the intraocular lens (IOL) in position after cataract surgery.During the operation, the front (anterior) portion of the lens capsule is carefully opened and the cataract is removed.The IOL is inserted into the remaining (posterior) portion of the capsule. The remaining portion of the capsule becomes clouded in about 25% of cataract surgery patients.When this occurs, patients experience symptoms similar to those from the original cataract.


Signs and Symptoms

  • Gradual decrease of vision
  • Blurred vision
  • Glare from lights and sun

Detection and Diagnosis

The eye care practitioner can diagnose posterior capsule opacification during a routine eye examination using a slit lamp microscope. It is more easily detected if the pupils are dilated. Potential acuity testing is often performed to determine the expected improvement of vision.


Treatment

A simple procedure called a YAG posterior capsulotomy is performed to restore vision lost from the clouded capsule. The YAG is a type of "cold" laser used to create a small opening in the center of the capsule, allowing a clear area for light to enter the eye. The procedure is painless, requires no anaesthesia, and has very little risk since no incision is required.

After the dilating drops wear off from the procedure, most patients notice an immediate improvement in vision. The improvement each person experiences is dependent on the extent of the capsular clouding and the overall eye health.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Scleritis

Scleritis is an inflammatory disease that affects the conjunctiva, sclera, and episclera (the connective tissue between the conjunctiva and sclera). It is associated with underlying systemic disease in about half of the cases. The diagnosis of scleritis may lead to the detection of underlying systemic disease. Rarely, scleritis is associated with an infectious problem.

The affected area of the sclera may be confined to small nodules, or it may cause generalized inflammation. Necrotizing scleritis, a more rare, serious type, causes thinning of the sclera. Severe cases of scleritis may also involve inflammation of other ocular tissues.

Scleritis affects women more frequently then men. It most frequently occurs in those who are in their 40's and 50's. The problem is usually confined to one eye, but may affect both.


Signs and Symptoms

  • Severe, boring pain that can awaken the patient
  • Local or general redness of the sclera and conjunctiva
  • Extreme tenderness
  • Light sensitivity and tearing (in some cases)
  • Decreased vision (if other ocular tissues are involved)

Detection and Diagnosis

Along with visual acuity testing, measurement of intraocular pressure, slit lamp examination, and ophthalmoscopy, the eye care practitioner may request a physician to order blood tests to rule out diseases affecting the body. If involvement of the back of the eye is suspected, the physician may order imaging tests such as CT Scan, MRI, or ultrasonography of the eye.


Treatment

Scleritis is treated with oral steroid and non-steroidal anti-inflammatory medication to reduce inflammation. Eye drops alone do not provide adequate treatment. In very severe cases of necrotizing scleritis, surgery may be required to graft scleral or corneal tissue over the area of thinned sclera.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Amblyopia

Amblyopia is a term used to describe an uncorrectable loss of vision in an eye that appears to be normal. It's commonly referred to as "lazy eye" and can occur for a variety of reasons.

A child's visual system is fully developed between approximately the ages of 9-11. Until then, children readily adapt to visual problems by suppressing or blocking out an image. If caught early, the problem can often be corrected and the vision preserved. However, after about age 11, it is difficult if not impossible to train the brain to use the eye normally.

Some causes of amblyopia include: strabismus (crossed or turned eye), congenital cataracts, cloudy cornea, droopy eyelid, unequal vision and uncorrected nearsightedness, farsightedness or astigmatism. Amblyopia may occur in various degrees depending on the severity of the underlying problem. Some patients just experience a partial loss; others are only able to recognize motion.

Patients with amblyopia lack binocular vision, or stereopsis - the ability to blend the images of both eyes together. Stereopsis is what allows us to appreciate depth. Without it, the ability to judge distance is impaired.


Signs and Symptoms

  • Poor vision in one or both eyes/li>
  • Squinting or closing one eye while reading or watching television
  • Crossed or turned eye
  • Turning or tilting the head when looking at an object
  • Note: Children rarely complain of poor vision. They are able to adapt very easily to most visual impairments. Parents must be very observant of young children and should have a routine eye exam performed by the age of 2-3 to detect potential problems.

Detection and Diagnosis

When amblyopia is suspected, the optometrist will evaluate the following: vision, eye alignment, eye movements, and fusion (the brain's ability to blend two images into a single image).


Treatment

The treatment for amblyopia depends on the underlying problem. In some cases, the strong eye is temporarily patched so the child is forced to use the weaker eye. For children with problems relating to a refractive error, glasses may be necessary to correct vision. Problems that impair vision such as cataracts or droopy eyelids often require surgery. Regardless of the treatment required, it is of utmost importance that intervention is implemented as early as possible before the child's brain learns to permanently suppress or ignore the eye.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Anatomy

A guide to the many parts of the human eye and how they function.


The ability to see is dependent on the actions of several structures in and around the eyeball. The graphic below lists many of the essential components of the eye's optical system.

anatomy external

anatomy globe

When you look at an object, light rays are reflected from the object to the cornea, which is where the miracle begins. The light rays are bent, refracted and focused by the cornea, lens, and vitreous. The job of the lens is to make sure the rays come to a sharp focus on the retina. The resulting image on the retina is upside-down. Here at the retina, the light rays are converted to electrical impulses which are then transmitted through the optic nerve, to the brain, where the image is translated and perceived in an upright position!

eye emmetrop

Think of the eye as a camera. A camera needs a lens and a film to produce an image. In the same way, the eyeball needs a lens (cornea, crystalline lens, vitreous) to refract, or focus the light and a film (retina) on which to focus the rays. If any one or more of these components is not functioning correctly, the result is a poor picture. The retina represents the film in our camera. It captures the image and sends it to the brain to be developed. The macula is the highly sensitive area of the retina. The macula is responsible for our critical focusing vision. It is the part of the retina most used. We use our macula to read or to stare intently at an object.

retina


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Artery Occlusion

A retinal artery occlusion occurs when the central retinal artery or one of the arteries that branch off it becomes blocked. This blockage is typically caused by a tiny embolus (blood clot) in the blood stream. The occlusion decreases the oxygen supply to the area of the retina nourished by the affected artery, causing permanent vision loss.

brao

In this photograph, the affected area of the retina is the pale, whitish-yellow region (blue arrow) that is normally supplied by the blocked artery. The surrounding reddish-orange area is healthy retina tissue.


Signs and Symptoms

• Transient loss of vision prior to the artery occlusion (in some cases).

Central artery occlusion

• Sudden, painless and complete loss of vision in one eye.

Branch artery occlusion

• Sudden, painless, partial loss of vision in one eye.


Detection and Diagnosis

Artery occlusion is diagnosed by examining the retina with an ophthalmoscope.


Treatment

Unfortunately, there is no treatment that can consistently restore vision lost from an artery occlusion. However, if it is caught within the first hour and treatment is initiated immediately, recovery is possible in rare cases.

The following conditions increase the risk of problems that may affect the vessels of the eye:

  • High cholesterol
  • Heart disease
  • Arteriosclerosis
  • Hypertension
  • Diabetes
  • Glaucoma

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Blepharitis

(Granulated Eyelids)


Blepharitis is a common inflammatory condition that affects the eyelids. It usually causes burning, itching and irritation of the lids. In severe cases, it may also cause styes, irritation and inflammation of the cornea (keratitis) and conjunctiva (conjunctivitis). Some patients have no symptoms at all.

Blepharitis is usually a chronic problem that can be controlled with extra attention to lid hygiene. However, it is sometimes caused by an infection and may require medication.


Signs and Symptoms

  • Sandy, itchy eyes
  • Red and/or swollen eyelids
  • Crusty, flaky skin on the eyelids
  • Dandruff

Detection and Diagnosis

Blepharitis is detected during a routine examination of the eyelids and lashes using a slit lamp microscope.


Treatment

The key to controlling blepharitis is to keep the eyelids and eyelashes clean. Begin by soaking a clean washcloth in hot tap water. Hold the washcloth to your cheek to test for temperature before placing it on the eyes. Place the compress on closed eyelids for five minutes, and then repeat. Next, gently scrub the eyelids with a washcloth or cotton swab soaked in a mixture of equal parts of baby shampoo and water. Afterward, rinse the lids thoroughly with warm water.

This treatment should be repeated two to three times daily for two weeks, and then reduced to once daily. Consult your eye care practitioner regarding the correct medical treatment. In some cases, anti-inflammatory and antibiotic drops or ointments are necessary for flare-ups or more severe cases.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Cataract

When cataracts are mentioned, people often think of a film that grows on their eyes causing them to see double or blurred images. However, a cataract does not form on the eye, but rather within the eye.

cat none

cat

Eye without a cataract

Eye with a cataract

A cataract is a clouding of the natural lens, the part of the eye responsible for focusing light and producing clear, sharp images. The lens is contained in a sealed bag or capsule. As old cells die they become trapped within the capsule. Over time, the cells accumulate causing the lens to cloud, making images look blurred or fuzzy. For most people, cataracts are a natural result of aging.

In fact, they are the leading cause of visual loss among adults 55 and older. Eye injuries, certain medications, and diseases such as diabetes and alcoholism have also been known to cause cataracts.

eye emmetrop

cataract


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Central Serous Chorioretinopathy

Central serous chorioretinopathy (CSCR) is a problem that affects the macula (central portion of the retina). The exact cause is not understood. CSCR occurs when a small break forms in the pigment layer of the retina. Fluid from the layer of blood vessels that lie underneath the retina seeps up through the break, causing a small detachment to form under the retina.

This problem is somewhat similar to a water blister that forms on the skin. The process is similar to CSCR: fluid collects beneath the skin's surface, causing the layers of skin to separate.

CSCR affects men more often then women and usually occurs between the ages of 25 and 50. Stress is thought to be linked to this problem. CSCR typically resolves spontaneously, but it can recur. In some cases, it may lead to moderate but permanent loss of central vision.


Signs and Symptoms

  • Blurred central vision
  • Wavy, distorted vision
  • Central blind spot

Detection and Diagnosis

Usually the eye care practitioner can diagnose CSCR with an examination of the retina using ophthalmoscopy. In most cases fluorescein angiography is used to gather additional information about the extent and severity of the problem.


Treatment

Most patients with CSCR do not require treatment. The fluid usually absorbs gradually over a period of months. Occasionally, steroid and non-steroidal anti-inflammatory eye drops are prescribed. In cases where visual recovery is delayed, laser treatment may be required to seal the leak and help the vision improve.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Chalazion

A chalazion (stye) is a small lump in the eyelid caused by obstruction of an oil producing or meibomian gland. Chalazia may occur in the upper or lower lids, causing redness, swelling and soreness in some cases.

chalazion

Signs and Symptoms

  • Raised, swollen bump on the upper or lower eye lid
  • Often red
  • May be tender and sore

Detection and Diagnosis

Patients often request an examination after an episode of pain and swelling of the lid. The eye care practitioner can make the diagnosis during a simple examination of the eyelids.


Treatment

In the early stages, chalazia may be treated at home with the repeated use of warm compresses for 15 - 20 minutes followed by several minutes of light lid massage. This helps to reduce the swelling and makes the lid more comfortable. However, if the chalazion does not diminish or recurs, medical attention may be necessary. This may include draining the chalazion along with the use of antibiotic and anti-inflammatory medications.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Chemical Burn

Know How to Treat a Chemical Burn?

Quick reactions can make the difference between sight and blindness


It can happen in the blink of an eye. While pouring liquid drain cleaner down a sink, some of the chemical splashes up in your face, hitting you squarely in the eye. Chemical injuries don't just happen in the workplace. Most homes have dozens of everyday products that pose tremendous danger to vision if they contact the eye.

The severity of the injury is related to whether the chemical is alkali or acid-based. Alkali chemicals are more destructive then acidic chemicals because of their ability to adhere to the eye and penetrate tissues. However, acid burns may be compounded by glass injuries caused by an explosion.

Alkali- based chemicals

  • Lime (cement, plaster, whitewash)

  • Drain cleaners

  • Lye

  • Metal polishes

  • Ammonia

  • Oven cleaners

Acid-based chemicals

  • Swimming pool acid (muriatic acid)

  • Battery (sulfuric) acid

Often, the difference between a serious but treatable injury and losing vision is a matter of understanding a few principles of ocular first aid.


Emergency care


First aid at home

  • Help the patient hold his or her head over a sink

  • Gently hold the lids apart with a cotton swab or dry cloth

  • Pour water over the eye, making sure to rinse inside the eyelids

  • Call your ophthalmologist

After chemical exposure, the first step is to immediately (within seconds) begin flushing the eye with water. If the accident occurs in an industrial setting, special irrigating facilities should be available. If the injury happens at home, begin flushing the eye with water right away, call for help immediately and contact your local ophthalmologist.

The easiest way to irrigate at home is for the patient to hold his or her head over a sink while the helper continuously pours water over the eye with a glass or cup.It is important to gently hold the lids apart while irrigating in order to rinse underneath the lids and wash away as much of the chemical as possible. Using a dry cloth is helpful because the lids are difficult to hold back when they are wet. Continue flushing the eye for approximately 20 minutes.


Secondary care at the ophthalmologist's office

If possible, bring the chemical used at the time of the accident to the doctor's office. The type of chemical, concentration, and key ingredients may give the doctor valuable information needed for treatment. The doctor may continue irrigation to insure that the chemical is diluted as much as possible. The eye will be carefully examined under magnification to determine the extent of the injury and whether there are any foreign particles imbedded in the eye.


An ounce of prevention...

Taking care to prevent chemical injuries is the best first aid. Follow these simple steps to reduce your risk:

  • Follow package directions and warnings before using chemicals

  • When using chemicals, always wear safety glasses

  • Never put your face over a drain after applying chemicals

The chance of regaining useful vision following a chemical accident is dependent on the nature and type of injury. However, knowing how to initiate treatment at home greatly increases the odds of recovery and saving vision.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Choroidal Neovascular Membrane (CNVM)

Choroidal neovascular membrane (CNVM) is a problem that is related to a wide variety of retinal diseases, but is most commonly linked to age-related macular degeneration. With CNVM, abnormal blood vessels stemming from the choroid (the blood vessel-rich tissue layer just beneath the retina) grow up through the retinal layers. Imagine the abnormal blood vessels as weeds creeping up through the cracks of a pavement. These new vessels are very fragile and break easily, causing blood and fluid to pool within the layers of the retina.

As the vessels leak, they disturb the delicate retinal tissue, causing the vision to deteriorate. The severity of the symptoms depends on the size of the CNVM and its proximity to the macula. Patients' symptoms may be very mild such as a blurry or distorted area of vision, or more severe, like a central blind spot.

cnvm

Signs and Symptoms

  • Blurred, grayed-out areas
  • Distorted vision
  • Central blind spot

Detection and Diagnosis

A simple vision test called an Amsler Grid should always be done first for patients who notice a problem with their central vision. This test provides the eye care practitioner with vital information about the location and severity of the problem. CNVM is usually difficult to diagnose by simply looking at the retina with an ophthalmoscope. A special dye test called a fluorescein angiogram is used to study the circulation of the retina and show areas of leaking blood vessels.


Treatment

The appropriate treatment is dependent on several factors such as: size and location of the membrane and the amount of time that passed since the symptoms first began. If the CNVM is small, compact, and caught very early, a delicate surgery called a sub-foveal excision can be performed to remove it. This procedure has the most risk but also offers the patient the best possibility of visual improvement.

Laser photocoagulation, a procedure that seals leaking blood vessels, is the simplest and most common treatment for CNVM. It is reserved for patients with bleeding outside of the central retina because it creates a scar that affects the vision. Treating the retina with laser gives the surgeon the most control over placement and size of the scar. Allowing an undiagnosed leak to resolve on its own usually causes a much more devastating affect on the vision.

Unfortunately, for some patients, no treatment is appropriate. All patients with CNVM should monitor their vision with an Amsler Grid and report any changes to their eye care practitioner immediately.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Cogan's Dystrophy

(Map-Dot-Fingerprint Dystrophy)

cogans

Cogan's Dystrophy is a disease that affects the cornea. It is commonly called Map-Dot-Fingerprint Dystrophy because of microscopic dot and fingerprint-like patterns that form within the layers of the cornea.

The cornea is comprised of five layers. Cogan's affects the superficial cornea layer called the epithelium. The epithelium's bottom, or basement layer of cells becomes thickened and uneven. This weakens the bond between the cells and sometimes causes the epithelium to become loosened and slough off in areas. This problem is called corneal erosion.

Even though this disease is commonly known as a dystrophy (a term that describes genetic diseases), Cogan's is not necessarily an inherited problem. It often affects both eyes and is typically diagnosed after the age of 30. Cogan's usually becomes progressively worse with age.


Signs and Symptoms

Some patients with Cogan's dystrophy have no symptoms at all. The symptoms among patients may may vary widely in severity and include:

  • Light sensitivity

  • Glare

  • Fluctuating vision

  • Blurred vision

  • Irregular astigmatism (uneven corneal surface)

  • Mild to extreme irritation and discomfort that is worse in the morning


Detection and Diagnosis

The eye care practitioner examines the layers of the cornea with a slit lamp microscope. In some cases, corneal topography may be needed to evaluate and monitor astigmatism resulting from the disease.


Treatment

The treatment for Cogan's is dependent on the severity of the problem. The first step is to lubricate the cornea with artificial tears to keep the surface smooth and comfortable. Lubricating ointments are recommended at bedtime so the eyes are more comfortable in the morning. Salt solution drops or ointments such as sodium chloride are often prescribed to reduce swelling and improve vision.Gas permeable contact lenses are occasionally fitted for patients with irregular astigmatism to create a smooth, even corneal surface and improve vision.

For patients with recurrent corneal erosion, soft, bandage contact lenses may be used to keep the eye comfortable and allow the cornea to heal. In some cases, laser treatment may be beneficial. The surgeon removes the epithelium with an Excimer laser, creating a regular, smooth surface. The epithelium quickly regenerates, usually within a matter of days, forming a better bond with the underlying cell layer.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Colour Blindness

Colour blindness may be a hereditary condition or caused by disease of the optic nerve or retina. Acquired colour vision problems only affect the eye with the disease and may become progressively worse over time. Patients with a colour vision defect caused by disease usually have trouble discriminating blues and yellows.

Inherited colour blindness is most common, affects both eyes, and does not worsen over time. This type is found in about 8% of males and 0.4% of females. These colour problems are linked to the X chromosome and are almost always passed from a mother to her son.

Colour blindness may be partial (affecting only some colours), or complete (affecting all colours). Complete colour blindness is very rare. Those who are completely colour blind often have other serious eye problems as well.

Photoreceptors called cones allow us to appreciate colour. These are concentrated in the very centre of the retina and contain three photosensitive pigments: red, green and blue. Those with defective colour vision have a deficiency or absence in one or more of these pigments. Those with normal colour vision are referred to as trichromats. People with a deficiency in one of the pigments are called anomalous trichromats (the most common type of colour vision problem.) A dichromat has a complete absence in one cone pigment.


Signs and Symptoms

The symptoms of colour blindness are dependent on several factors, such as whether the problem is congenital, acquired, partial, or complete.

  • Difficulty distinguishing reds and greens (most common)

  • Difficulty distinguishing blues and greens (less common)

The symptoms of more serious inherited colour vision problems and some acquired types' problems may include:

  • Objects appear as various shades of gray (this occurs with complete colour blindness and is very rare)

  • Reduced vision

  • Nystagmus


Detection and Diagnosis

Colour vision deficiency is most commonly detected with special coloured charts called the Ishihara Test Plates. On each plate is a number composed of coloured dots. While holding the chart under good lighting, the patient is asked to identify the number. Once the colour defect is identified, more detailed colour vision tests may be performed.


Treatment

There is no treatment or cure for colour blindness. Those with mild colour deficiencies learn to associate colours with certain objects and are usually able to identify colour as everyone else does. However, they are unable to appreciate colour in the same way as those with normal colour vision.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Computer Vision Syndrome

Computer vision syndrome (CVS) is a term that describes eye-related problems and the other symptoms caused by prolonged computer use. As our dependence on computers continues to grow, an increasing number of people are seeking medical attention for eye strain and irritation, along with back, neck, shoulder, and wrist soreness.

A

Magnified view of a printed letter

A pix

Magnified view of a letter on a computer screen

These problems are more noticeable with computer tasks than other near work because letters on the screen are formed by tiny dots called pixels, rather than a solid image. This causes the eye to work a bit harder to keep the images in focus.

There is no scientific evidence that computer screens are harmful to the eyes. A common myth is that eye strain caused by reading and close work is damaging to the eyes. This is not true; however, those who work at computers often experience many frustrating symptoms.


Signs and Symptoms

  • Blurred near vision
  • Difficulty focusing from close to far and back again
  • Sore, irritated eyes
  • Dry eyes
  • Red eyes
  • Eye fatigue
  • Headaches that disappear after a period of rest
  • Irritation and discomfort while wearing contact lenses
  • Soreness and pain in the neck, shoulder, and back

Detection and Diagnosis

Your eye care practitioner will perform a complete eye examination that includes: near and distance visual acuity, refraction, tonometry, and an examination of the eye structures with a slit lamp microscope and ophthalmoscopy.

It is important to provide the eye care practitioner with detail about your work environment, work habits, and detail about the symptoms and their patterns. Bring your prescription glasses with you so the eye care practitioner can determine if they are appropriate for computer work.


Treatment

The three main areas that should be addressed when treating CVS patients are: eye-related problems, work environment, and posture.

Eye-related problems

  • Make sure the glasses are the correct prescription and designed for working at a computer. Patients who wear bifocals may find themselves keeping their head in an uncomfortable position in order to see the screen. Your optometrist will determine the glasses best suited for the task, and if necessary, prescribe glasses with an adjusted bifocal height and width.

  • Blink frequently and instill artificial tears as needed. One of the biggest complaints of patients with CVS is dry, irritated, red eyes. This is common because we tend to blink less when reading.

  • Stop periodically and look away from the computer screen. Looking up relaxes the eye's focusing mechanism and reduces the problem of eye strain.

Work environment

cvsposture incorrect

Incorrect hand position

cvsposture correct
Correct hand position
  • Sit approximately 24" from the monitor. Sitting atthe appropriate working distance from the computer screen maximizes the clarity of the text and images.

  • Adjust the monitor so the centre is slightly below eye level. This keeps the neck in the most natural position and reduces soreness and fatigue.

  • Minimize glare on the screen. Arrange the lighting and desk to eliminate glare on the monitor. An anti-reflective screen placed over the monitor is sometimes helpful.

Posture and work habits

  • Maintain good posture. Sitting up straight with your feet on the floor can reduce back stress. Use a cushion for the lower back if necessary.

  • Keep your wrists straight when typing. Avoid resting your wrists on the keyboard.

  • Place the mouse and keyboard at the same level, keeping them close to the body. The keyboard level should at a slightly lower level than the desk.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Conjunctivitis

(Pink Eye)


Conjunctivitis, commonly known as pink eye, is an infection of the conjunctiva (the outer-most layer of the eye that covers the sclera).

conjunctivitisThe three most common types of conjunctivitis are: viral, allergic, and bacterial. Each requires different treatments. With the exception of the allergic type, conjunctivitis is typically contagious.

The viral type is often associated with an upper respiratory tract infection, cold, or sore throat. The allergic type occurs more frequently among those with allergic conditions.When related to allergies, the symptoms are often seasonal. Allergic conjunctivitis may also be caused by intolerance to substances such as cosmetics, perfume, or drugs.Bacterial conjunctivitis is often caused by bacteria such as staphylococcus and streptococcus. The severity of the infection depends on the type of bacteria involved.


Signs and Symptoms

Viral conjunctivitis

  • Watery discharge
  • Irritation
  • Red eye
  • Infection usually begins with one eye, but may spread easily to the other eye

Allergic conjunctivitis

  • Usually affects both eyes
  • Itching
  • Tearing
  • Swollen eyelids

Bacterial conjunctivitis

  • Stringy discharge that may cause the lids to stick together, especially after sleeping
  • Swelling of theconjunctiva
  • Redness
  • Tearing
  • Irritation and/or a gritty feeling
  • Usually affects only one eye, but may spread easily to the other eye

Detection and Diagnosis

Conjunctivitis is diagnosed during a routine eye exam using a slit lamp microscope. In some cases, cultures are taken to determine the type of bacteria causing the infection.


Treatment

The appropriate treatment depends on the cause of the problem.

For the allergic type, cool compresses and artificial tears sometimes relieve discomfort in mild cases. In more severe cases, non-steroidal anti-inflammatory medications and antihistamines may be prescribed. Some patients with persistent allergic conjunctivitis may also require topical steroid drops.

Bacterial conjunctivitis is usually treated with antibiotic eye drops or ointments that cover a broad range of bacteria.

Like the common cold, there is no cure for viral conjunctivitis; however, the symptoms can be relieved with cool compresses and artificial tears (found in most pharmacies). For the worst cases, topical steroid drops may be prescribed to reduce the discomfort from inflammation. Viral conjunctivitis usually resolves within 3 weeks.

To avoid spreading infection, take these simple steps:

  • Disinfect surfaces such as doorknobs and counters with diluted bleach solution
  • Don't swim (some bacteria can be spread in the water)
  • Avoid touching the face
  • Wash hands frequently
  • Don't share towels or washcloths
  • Do not reuse handkerchiefs (using a tissue is best)
  • Avoid shaking hands

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Cystoid Macular Oedema
cme w inset

In this retinal photograph, the swelling is the yellowish spots (arrow) in the macula.

Cystoid macular oedema (CME), or swelling of the macula, typically occurs as a result of disease, injury or more rarely, eye surgery. Fluid collects within the layers of the macula, causing blurred, distorted central vision. CME rarely causes a permanent loss of vision, but the recovery is often a slow, gradual process. The majority of patients recover in 2 to 15 months.


Signs and Symptoms

  • Blurred central vision
  • Distorted vision (straight lines may appear wavy)
  • Vision is tinted pink
  • Light sensitivity

Detection and Diagnosis

It is very difficult to detect CME during a routine examination. A diagnosis is often based on the patient's symptoms and a special dye test called a fluorescein angiogram (FA).


Treatment

The first line of treatment for CME is usually anti-inflammatory drops. In certain cases, medication is injected near the back of the eye for a more concentrated effect. Oral medications are sometimes prescribed to reduce the swelling.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Cytomegalovirus

The cytomegalovirus (CMV) is related to the herpes virus and is present in almost everyone. Normally, most people's immune systems are able to fight the virus, preventing it from causing problems in their bodies. However, when the immune system is suppressed because of disease (HIV), organ or bone marrow transplant, or chemotherapy, the CMV virus can cause damage and disease to the eye and the rest of the body.

CMV is the most common type of virus that infects those who are HIV positive. It affects the eye in about 30% of the cases by causing damage to the retina. This is called CMV retinitis. The likelihood of developing CMV retinitis increases as the CD4 cell count decreases.

CMV retinitis may affect one eye at first, but usually progresses to both eyes and becomes worse as the patient's ability to fight infection decreases. The virus is sight threatening and usually requires the care and treatment of a vitreo-retinal surgeon.Patients with CMV retinitis are at risk of retinal detachment, haemorrhages, and inflammation of the retina that can lead to permanent loss of vision and even blindness.


Signs and Symptoms

CMV retinitis usually causes symptoms, but not always.Patients with a condition that suppresses the immune system should watch for the following eye symptoms while under the care of a physician.

  • Floaters (spots, bugs, spider webs)
  • Light flashes
  • Blind spots
  • Blurred vision
  • Obstructed areas of vision
  • Sudden decrease of vision

Detection and Diagnosis

Most patients with CMV retinitis are referred for eye treatment by another physician. The vitreo-retinal surgeon diagnoses CMV retinitis by thoroughly examining the back of the eye using ophthalmoscopy. Fluorescein angiography may be needed to evaluate the circulatory system of the retina.


Treatment

When managing CMV retinitis, the doctor's goal is to slow the progression of the disease and to treat related eye problems. Anti-viral medications such as ganciclovir or foscarnet are often prescribed. These drugs can be administered orally, intravenously, injected directly into the eye or through an intravitreal implant.

cmv2Photographs of retinas affected with CMV retinitis.

normalretinaNormal (unaffected) retina


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Diabetic Retinopathy


diabetic

Diabetes is a disease that occurs when the pancreas does not secrete enough insulin or the body is unable to process it properly. Insulin is the hormone that regulates the level of sugar (glucose) in the blood. Diabetes can affect children and adults.


How does diabetes affect the retina?

Patients with diabetes are more likely to develop eye problems such as cataracts and glaucoma, but the disease's effect on the retina is the main threat to vision. Most patients develop diabetic changes in the retina after approximately 20 years. The effect of diabetes on the eye is called diabetic retinopathy.

Over time, diabetes affects the circulatory system of the retina. The earliest phase of the disease is known as background diabetic retinopathy. In this phase, the arteries in the retina become weakened and leak, forming small, dot-like haemorrhages. These leaking vessels often lead to swelling or oedema in the retina and decreased vision.

The next stage is known as proliferative diabetic retinopathy. In this stage, circulation problems cause areas of the retina to become oxygen-deprived or ischaemic. New, fragile, vessels develop as the circulatory system attempts to maintain adequate oxygen levels within the retina. This is called neovascularization. Unfortunately, these delicate vessels haemorrhage easily. Blood may leak into the retina and vitreous, causing spots or floaters, along with decreased vision.

In the later phases of the disease, continued abnormal vessel growth and scar tissue may cause serious problems such as retinal detachment.


Signs and Symptoms

The effect of diabetic retinopathy on vision varies widely, depending on the stage of the disease. Some common symptoms of diabetic retinopathy are listed below, however, diabetes may cause other eye symptoms.

  • Blurred vision (this is often linked to blood sugar levels)
  • Floaters and flashes
  • Sudden loss of vision

Detection and Diagnosis

Diabetic patients require routine eye examinations so related eye problems can be detected and treated as early as possible. Most diabetic patients are frequently examined by an internist or endocrinologist who in turn work closely with the eye care practitioner.

The diagnosis of diabetic retinopathy is made following a detailed examination of the retina with an ophthalmoscope. Most patients with diabetic retinopathy are referred to vitreo-retinal surgeons who specialize in treating this disease.


Treatment

Diabetic retinopathy is treated in many ways depending on the stage of the disease and the specific problem that requires attention. The retinal surgeon relies on several tests to monitor the progression of the disease and to make decisions for the appropriate treatment. These include: fluorescein angiography, retinal photography, and ultrasound imaging of the eye.

The abnormal growth of tiny blood vessels and the associated complication of bleeding is one of the most common problems treated by vitreo-retinal surgeons. Laser surgery called pan retinal photocoagulation (PRP) is usually the treatment of choice for this problem.

With PRP, the surgeon uses laser to destroy oxygen-deprived retinal tissue outside of the patient's central vision. While this creates blind spots in the peripheral vision, PRP prevents the continued growth of the fragile vessels and seals the leaking ones. The goal of the treatment is to arrest the progression of the disease.

Vitrectomy is another surgery commonly needed for diabetic patients who suffer a vitreous haemorrhage (bleeding in the gel-like substance that fills the centre of the eye). During a vitrectomy, the retina surgeon carefully removes blood and vitreous from the eye, and replaces it with clear salt solution (saline). At the same time, the surgeon may also gently cut strands of vitreous attached to the retina that create traction and could lead to retinal detachment or tears.

Patients with diabetes are at greater risk of developing retinal tears and detachment. Tears are often sealed with laser surgery. Retinal detachment requires surgical treatment to reattach the retina to the back of the eye. The prognosis for visual recovery is dependent on the severity of the detachment.


Prevention

Researchers have found that diabetic patients who are able to maintain appropriate blood sugar levels have fewer eye problems than those with poor control. Diet and exercise play important roles in the overall health of those with diabetes.

Diabetics can also greatly reduce the possibilities of eye complications by scheduling routine examinations with an eye care practitioner. Many problems can be treated with much greater success when caught early.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Dry Eye Syndrome

Dry eye syndrome is one of the most common problems treated by eye care practitioners. Millions of people worldwide suffer from dry eyes. It is usually caused by a problem with the quality of the tear film that lubricates the eyes.

Tears are comprised of three layers. The mucous layer coats the cornea, the eye's clear outer window, forming a foundation so the tear film can adhere to the eye. The middle aqueous layer provides moisture and supplies oxygen and other important nutrients to the cornea. This layer is made up of 98 percent water along with small amounts of salt, proteins and other compounds. The outer lipid layer is an oily film that seals the tear film on the eye and helps to prevent evaporation.

Tears are formed in several glands around the eye. The water layer is produced in the lacrimal gland, located under the upper eyelid. Several smaller glands in the lids make the oil and mucous layers. With each blink, the eyelids spread the tears over the eye. Excess tears flow into two tiny drainage ducts in the corner of the eye by the nose. These ducts lead to tiny canals that connect to the nasal passage. The connection between the tear ducts and the nasal passage is the reason that crying causes a runny nose.

In addition to lubricating the eye, tears are also produced as a reflex response to outside stimuli such as injury or emotion. However, reflex tears do little to soothe a dry eye, which is why someone with watery eyes may still complain of irritation.

Dry eye syndrome has many causes. One of the most common reasons for dryness is simply the normal aging process. As we grow older, our bodies produce less oil - 60% less at age 65 then at age 18. This is more pronounced in women, who tend to have drier skin then men. The oil deficiency also affects the tear film. Without as much oil to seal the watery layer, the tear film evaporates much faster, leaving dry areas on the cornea.

Many other factors, such as hot, dry or windy climates, high altitudes, air-conditioning and cigarette smoke also cause dry eyes. Many people also find their eyes become irritated when reading or working on a computer. Stopping periodically to rest and blink keeps the eyes more comfortable.

Contact lens wearers may also suffer from dryness because the contact lenses absorb the tear film, causing proteins to form on the surface of the lens. Certain medications, thyroid conditions, vitamin A deficiency, and diseases such as Parkinson's and Sjogren's can also cause dryness. Women frequently experience problems with dry eyes as they enter menopause because of hormonal changes.


Signs and Symptoms

punctal plugs

  • Itching
  • Burning
  • Irritation
  • Redness
  • Blurred vision that improves with blinking
  • Excessive tearing
  • Increased discomfort after periods of reading, watching TV, or working on a computer

Detection and Diagnosis

There are several methods to test for dry eyes. The eye care practitioner will first determine the underlying cause by measuring the production, evaporation rate and quality of the tear film. Special drops that highlight problems that would be otherwise invisible are particularly helpful to diagnose the presence and extent of the dryness.


Treatment

When it comes to treating dry eyes, everyone's needs are a little different. Many find relief simply from using artificial tears on a regular basis. Some of these products are watery and alleviate the symptoms temporarily; others are thicker and adhere to the eye longer. Preservative-free tears are recommended because they are the most soothing and have fewer additives that could potentially irritate. Avoid products that whiten the eyes - they don't have adequate lubricating qualities and often make the problem worse.

Closing the opening of the tear drain in the eyelid with special inserts called punctal plugs is another option. This works like closing a sink drain with a stopper. These special plugs trap the tears on the eye, keeping it moist. This may be done on a temporary basis with a dissolvable collagen plug, or permanently with a silicone plug.

There are also simple lifestyle changes that can significantly improve irritation from dry eyes. For example, drinking eight to ten glasses of water each day keeps the body hydrated and flushes impurities. Make a conscious effort to blink frequently - especially when reading or watching television. Avoid rubbing the eyes. This only worsens the irritation.

Treating dry eye problems is important not only for comfort, but also for the health of the cornea.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Ectropion

Patients with ectropion have a sagging lower eyelid that leaves the eye exposed and dry. It is caused by a lack of tone of the delicate muscles that hold the lid taut against the eye. Excessive tearing is common with ectropion, but wiping the tears away only causes the lid to sag more. Ectropion is most common among people over the age of 60.

Signs and Symptoms

ectropion

  • Irritation
  • Burning
  • Gritty, sandy feeling
  • Excessive tearing
  • Red, irritated eyelid

Detection and Diagnosis

Ectropion can be diagnosed with a routine eye examination.


Treatment

The irritation can be temporarily relieved with artificial tears and ointments to lubricate the eye; however, surgery to tighten the lid is usually necessary to correct this problem.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Entropion

Overview

Entropion, an eyelid that turns inward, is a problem that typically affects the lower lid. It usually stems from a muscle spasm; however, it can also be caused by scarring from trauma or inflammation from certain diseases that involve the eyelids.

When the eyelid turns inward, the lashes rub against the eye, resulting in irritation, scratchiness, tearing and redness. Surgery is often required to correct the problem.

Signs and Symptoms
  • Tearing

  • Burning

  • Irritation

  • Sandy, gritty feeling

  • Red eye

Detection and Diagnosis

Entropion can be detected during a routine eye examination. A slit lamp microscope is used to examine the effects of the in-turned eyelashes on the surface of the eye.

Treatment

The most effective treatment for entropion is surgery, although some patients find temporary relief by pulling the lower lid down with a piece of tape. Artificial tears are also helpful to ease the irritation caused from the lashes rubbing against the eye.

Episcleritis

Episcleritis is an inflammatory condition of the connective tissue between the conjunctiva and sclera, known as the episclera. The eye's red appearance makes it look similar to conjunctivitis, or pink eye, but there is no discharge or tearing. It usually has no apparent cause; however, it is sometimes associated with systemic inflammatory conditions such as arthritis, lupus, and inflammatory bowel disease. Rosacea, herpes simplex, gout, tuberculosis, and other diseases are also occasionally underlying causes.

Women are typically affected by episcleritis more frequently than men. It characteristically occurs in people who are in their 30's and 40's and is often a recurrent problem.


Signs and Symptoms

  • Generalized or local redness.
  • Mild soreness or discomfort.

Detection and Diagnosis

Episcleritis is diagnosed with a slit lamp examination. The eye care practitioner will look for discharge, pain, and involvement of the underlying sclera to rule out other problems.


Treatment

Treatment for episcleritis is usually not needed. Chilled artificial tears can be used to soothe the eye and reduce mild inflammation. In more severe cases of episcleritis, mild steroids and anti-inflammatory medications are prescribed to reduce inflammation.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Flashes and Floaters

(Posterior Vitreous Detachment)

floaters

The space between the crystalline lens and the retina is filled with a clear, gel-like substance called vitreous. In a newborn, the vitreous has an egg-white consistency and is firmly attached to the retina. With age, the vitreous thins and may separate from the back of the eye. This is called posterior vitreous detachment (PVD), a very common, usually harmless condition.

As the vitreous pulls free from the retina, it is often accompanied by light flashes or floaters. Floaters are caused by tiny bits of vitreous gel or cells that cast shadows on the retina. Flashes occur when the vitreous tugs on the sensitive retinal tissue.

There are other more serious causes of flashes and floaters, however. Retinal tears, retinal detachment, infection, inflammation, haemorrhage, or an injury such as a blow to the head may also cause floaters and flashes. (Have you ever seen stars after bumping your head?) Occasionally, flashes of light are caused by neurological problems such as a migraine headache. When related to a headache, the flashes of light are seen in both eyes and usually lasts 20-30 minutes before the headache starts.


Signs and Symptoms

  • Black spots or "spider webs" that seem to float in the vision in a cluster or alone
  • Spots that move or remain suspended in one place
  • Flickering or flashing lights that are most prominent when looking at a bright background like a clear, blue sky

Symptoms that may indicate a more serious problem

  • Sudden decrease of vision along with flashes and floaters
  • Veil or curtain that obstructs part or all of the vision
  • Sudden increase in the number of floaters

Detection and Diagnosis

Notify your eye care practitioner immediately if you notice a sudden shower of floaters, new light flashes, a veil or curtain obstructing your vision, or any other change. The eye care practitioner will dilate your pupils with drops and examine the vitreous and retina inside the eye with an ophthalmoscope.


Treatment

Because of the risk, surgery is rarely indicated for PVD except when the floaters obscure the vision. In these cases, surgical removal of the vitreous (vitrectomy) may be considered only if the vision is significantly affected. This treatment is rarely needed since floaters typically become less bothersome over a period of weeks to months as they settle below the line of sight.

If the flashes and floaters are related to a problem other than a PVD, surgical treatment may be required.


Be proactive and monitor your vision

It is important to periodically assess the vision of each eye. Many problems can be detected early by simply comparing both eyes.

To test your vision:

  1. Cover one eye and pick a point to look at straight ahead
  2. Note the quality of your central and peripheral vision, noting any change
  3. Look for any obstructions, veils or curtains in your peripheral vision
  4. Watch for floaters, flashes
  5. Note the duration and intensity of the symptoms
  6. Cover fellow eye and repeat

Report any new symptoms or changes in vision to your eye care practitioner.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Fovea

The fovea (arrow) is the center most part of the macula.

This tiny area is responsible for our central, sharpest vision. A healthy fovea is the key for reading, watching television, driving, and other activities that require the ability to see detail. Unlike the peripheral retina, it has no blood vessels. Instead, it has a very high concentration of cones (photoreceptors responsible for color vision), allowing us to appreciate colour.

 

fovea

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Fuchs' Corneal Dystrophy

Fuchs' dystrophy is an inherited condition that affects the delicate inner layer (endothelium) of the cornea. The endothelium functions as a pump mechanism, constantly removing fluids from the cornea to maintain its clarity. Patients gradually lose these endothelial cells as the dystrophy progresses. Once lost, the endothelial cells do not grow back, but instead spread out to fill the empty spaces. The pump system becomes less efficient, causing corneal clouding, swelling and eventually, reduced vision.

In the early stages, Fuchs' patients notice glare and light sensitivity. As the dystrophy progresses, the vision may seem blurred in the morning and sharper later in the day. This happens because the internal layers of the cornea tend to retain more moisture during sleep, that evaporates when the eyes are open. As the dystrophy worsens, the vision becomes continuously blurred.

Fuchs' affects both eyes and is slightly more common among women than men. It generally begins at 30-40 years of age and gradually progresses. If the vision becomes significantly impaired, a corneal transplant may be indicated. Sometimes corneal transplant (also known as penetrating keratoplasty or PKP) is performed along with cataract and intraocular lens implant surgery.


Signs and Symptoms

  • Hazy vision that is often most pronounced in the morning
  • Fluctuating vision
  • Glare when looking at lights
  • Light sensitivity
  • Sandy, gritty sensation

Detection and Diagnosis

Fuchs' is detected by examining the cornea with a slit lamp microscope that magnifies the endothelial cells thousands of times. The health of the endothelium is evaluated and monitored with pachymetry and specular microscopy.


Treatment

fuchs

Fuchs' cannot be cured; however, with certain medications, blurred vision resulting from the corneal swelling can be controlled. Salt solutions such as sodium chloride drops or ointment are often prescribed to draw fluid from the cornea and reduce swelling. Another simple technique that reduces moisture in the cornea is to hold a hair dryer at arm's length, blowing air into the face with the eyes closed. This technique draws moisture from the cornea, temporarily decreases swelling, and improves the vision.

Corneal transplant is indicated when the vision deteriorates to the point that it impairs the patient's ability to function normally.

This is a highly magnified photo of the layers of the cornea. The "oedema" caused by Fuchs' can be seen as the mottled appearance.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Glaucoma

Glaucoma is a disease caused by increased intraocular pressure (IOP) resulting either from a malformation or malfunction of the eye's drainage structures. Left untreated, an elevated IOP causes irreversible damage to the optic nerve and retinal fibres resulting in a progressive, permanent loss of vision. However, early detection and treatment can slow, or even halt the progression of the disease.


What causes glaucoma?

The eye constantly produces aqueous, the clear fluid that fills the anterior chamber (the space between the cornea and iris). The aqueous filters out of the anterior chamber through a complex drainage system. The delicate balance between the production and drainage of aqueous determines the eye's intraocular pressure (IOP). Most people's IOPs fall between 8 and 21. However, some eyes can tolerate higher pressures than others. That's why it may be normal for one person to have a higher pressure than another.�


Common types of glaucoma

Open Angle

Open angle (also called chronic open angle or primary open angle) is the most common type of glaucoma. With this type, even though the anterior structures of the eye appear normal, aqueous fluid builds up within the anterior chamber, causing the IOP to become elevated. Left untreated, this may result in permanent damage of the optic nerve and retina. Eye drops are generally prescribed to lower the eye pressure. In some cases, surgery is performed if the IOP cannot be adequately controlled with medical therapy.�

Acute Angle Closure

Only about 10% of the population with glaucoma have this type. Acute angle closure occurs because of an abnormality of the structures in the front of the eye. In most of these cases, the space between the iris and cornea is more narrow than normal, leaving a smaller channel for the aqueous to pass through. If the flow of aqueous becomes completely blocked, the IOP rises sharply, causing a sudden angle closure attack.

While patients with open angle glaucoma don't typically have symptoms, those with angle closure glaucoma may experience severe eye pain accompanied by nausea, blurred vision, haloes around lights, and a red eye. This problem is an emergency and should be treated by an ophthalmologist immediately. If left untreated, severe and permanent loss of vision will occur in a matter of days.

Secondary Glaucoma

This type occurs as a result of another disease or problem within the eye such as: inflammation, trauma, previous surgery, diabetes, tumor, and certain medications. For this type, both the glaucoma and the underlying problem must be treated.

Congenital

This is a rare type of glaucoma that is generally seen in infants. In most cases, surgery is required.


Signs and Symptoms

Glaucoma is an insidious disease because it rarely causes symptoms. Detection and prevention are only possible with routine eye examinations. However, certain types, such as angle closure and congenital, do cause symptoms.

Angle Closure (emergency)

  • Sudden decrease of vision
  • Extreme eye pain
  • Headache
  • Nausea and vomiting
  • Glare and light sensitivity

Congenital

  • Tearing
  • Light sensitivity
  • Enlargement of the cornea

Detection and Diagnosis

glauc discs
The above photos show progressive optic nerve damage (indicated by the cup to disc ratio) caused by glaucoma.

Notice the pale appearance of the nerve with the 0.9 cup as compared to the nerve with the 0.3 cup.

Because glaucoma does not cause symptoms in most cases, those who are 40 or older should have an annual examination including a measurement of the intraocular pressure. Those who are glaucoma suspects may need additional testing.

The glaucoma evaluation has several components. In addition to measuring the intraocular pressure, the eye care practitioner will also evaluate the health of the optic nerve (ophthalmoscopy), test the peripheral vision (visual field test), and examine the structures in the front of the eye with a special lens (gonioscopy) before making a diagnosis.

The eye care practitioner evaluates the optic nerve and grades its health by noting the cup to disc ratio. This is simply a comparison of the cup (the depressed area in the center of the nerve) to the entire diameter of the optic nerve. As glaucoma progresses, the area of cupping, or depression, increases. Therefore, a patient with a higher ratio has more damage.

The progression of glaucoma is monitored with a visual field test. This test maps the peripheral vision, allowing the eye care practitioner to determine the extent of vision loss from glaucoma and a measure of the effectiveness of the treatment. The visual field test is periodically repeated to verify that the intraocular pressure is being adequately controlled.

The structures in the front of the eye are normally difficult to see without the help of a special gonioscopy lens. This special mirrored contact lens allows the eye care practitioner to examine the anterior chamber and the eye's drainage system.


Treatment

Most patients with glaucoma require only medication to control the eye pressure. Sometimes, several medications that complement each other are necessary to reduce the pressure adequately.

Surgery is indicated when medical treatment fails to lower the pressure satisfactorily. There are several types of procedures, some involve laser and can be done in the office, others must be performed in the operating theatre. The objective of any glaucoma operation is to allow fluid to drain from the eye more efficiently.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Headaches

Headaches may occur for any number of reasons including: sinus conditions, hypertension, allergies, tumors, hormonal changes, and most frequently, stress. They are not usually associated with problems related to the eyes.


Migraine headaches

Migraine, a type of headache that is often hereditary, usually first surfaces between the ages of 15 and 30. They are most common among women and are thought to be related to stress and some foods.

Migraine headaches may cause visual symptoms such as light flashes, temporary blind spots, and blurred vision. Migraines are thought to be caused by the dilation and constriction of arteries in the head. These headaches can be extremely painful. The pain is often limited to one side of the head, and may be accompanied by nausea and vomiting.

In many cases, migraines are believed to be brought on by stress. This "Friday night" headache often follows the stress relief of a frenetic week during which the blood vessels in the head relax and constrict. Certain foods and additives such as chocolate, alcohol, dairy, and MSG are also attributed to migraines. However, for many, the cause is variable and extremely difficult to pinpoint.


Signs and Symptoms

Eye-related headaches typically occur after extended periods of reading, watching television, computer work, or other close work that requires intense concentration. This type of headache usually disappears after a period of rest. In some cases, headaches may be caused by eyestrain related to eyeglasses. A tendency for the eyes to cross or drift outward may also bring on headaches.

One eye problem known to cause an intense headache is angle-closure glaucoma. With this type of glaucoma, the headache is only part of the problem. Patients suffering from an angle-closure attack also may experience nausea, intense pain around the eye,blurred vision, and haloes around lights.

Headaches caused by eye disease are unique in their symptoms and types of pain. It is important to make detailed notes of your symptoms, type of pain, lifestyle and what you were doing when the headache began. This information is very helpful to the physician to diagnose the type and cause of the headache you are experiencing.

The symptoms from headaches can be extremely variable and depend on the underlying problem. Because the scope of the various types and causes is so immense, the following headaches are described with the typical symptoms as they relate to the eye.

Headaches related to eye fatigue:

  • Headaches that begin after an extended period of reading, computer use, watching television, or close work
  • Burning eyes
  • Fatigue

Migraines

  • Throbbing pain
  • Sensitivity to light and sound
  • Nausea and vomiting
  • Visual "aura" including: light flashes, jagged lights, missing areas of vision

Acute angle-closure glaucoma

  • Intense headache that is usually centralized over brow area
  • Nausea and vomiting
  • Glare or haloes around lights

Detection and Diagnosis

Your doctor will routinely obtain a complete history and perform a thorough physical examination to rule out systemic causes of the headache. Your eye care practitioner will verify that no eye-related problems are bringing on the headache.


Treatment

Stress relief, control of blood pressure, or medication to maintain appropriate hormonal levels may be necessary. New glasses or different work lighting may be prescribed by your eye care practitioner.

If you have persistent headaches, it is important to consult your medical doctor about them for a medical evaluation.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Herpes Simplex Eye Disease

Herpes simplex is a very common virus affecting the skin, mucous membranes, nervous system, and the eye. There are two types of herpes simplex. Type I causes cold sores or fever blisters and may involve the eye. Type II is sexually transmitted and rarely causes ocular problems.

Nearly everyone is exposed to the virus during childhood. Herpes simplex is transmitted through bodily fluids, and children are often infected by the saliva of an adult. The initial infection is usually mild, causing only a sore throat or mouth. After exposure, herpes simplex usually lies dormant in the nerves that supply the eye and skin.

Later on, the virus may be reactivated by stress, heat, running a fever, sunlight, hormonal changes, trauma, or certain medications. It is more likely to recur in people who have diseases that suppress their immune system. In some cases, the recurrence is triggered repeatedly and becomes a chronic problem.

When the eye is involved, herpes simplex typically affects the eyelids, conjunctiva, and cornea. Keratitis (swelling caused by the infection), a problem affecting the cornea, is often the first ocular sign of the disease. In some cases, the infection extends to the middle layers of the cornea, increasing the possibility of permanent scarring. Some patients develop uveitis, an inflammatory condition that affects other eye tissues.

Signs and Symptoms

herpes dendrite

  • Pain
  • Red eye
  • Tearing
  • Light sensitivity
  • Irritation, scratchiness
  • Decreased vision (dependent on the location and extent of the infection)

Detection and Diagnosis

Herpes simplex is diagnosed with a slit lamp examination. Tinted eye drops that highlight the affected areas of the cornea may be instilled to help the eye care practitioner evaluate the extent of the infection.


Treatment

Treatment of herpes simplex keratitis depends on the severity. An initial outbreak is typically treated with topical and sometimes oral anti-viral medication. The ophthalmologist may gently scrape the affected area of the cornea to remove the diseased cells. Patients who experience permanent corneal scarring as a result of severe and recurrent infections may require a corneal transplant to restore their vision.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Herpes Zoster

Herpes zoster, commonly known as shingles, is caused by the same virus responsible for chicken pox. After the initial exposure, herpes zoster lies dormant in certain nerve fibres. It may become active as a result of many factors such as: aging, stress, suppression of the immune system, and certain medications.

Because of the layout of the nerves that herpes zoster resides in, it only affects one side of the body or face during an outbreak. It begins as a rash that lead to blisters and sores on the skin. When the nerve branch that supplies the eye is involved, the forehead, nose, and eyelids may also be affected. Sores on the nose are a key signal of possible eye involvement.

Herpes zoster can cause several problems with the eye and surrounding skin that may have long term effects. Inflammation and scarring of the cornea, along with conjunctivitis (inflammation of the conjunctiva) and iritis (inflammation of the iris) are typical problems that require treatment. In some cases, the retina and optic nerve are involved. Eye problems caused by severe or chronic outbreaks of herpes zoster may include: glaucoma, cataract, double vision, and scarring of the cornea and eyelids.

Many who experience this infection find it extremely painful. This acutely painful phase usually lasts several weeks; however, some continue to experience pain or neuralgia long after the outbreak has cleared. This is known as post-herpetic neuralgia.


Signs and Symptoms

Herpes zoster causes a wide range of problems affecting the skin and the eye. They range in severity depending on the extent of the outbreak. Some problems listed occur indirectly from the inflammation caused by the disease.

Problems affecting the body

  • Flu-like symptoms (fever, headache, fatigue)
  • Rash
  • Red, sensitive, sore skin
  • Blisters and sores on the skin
  • Pain (may be burning or throbbing), itching and tingling

Problems affecting the eye

  • Redness
  • Light sensitivity
  • Swollen eyelids
  • Dry eyes
  • Blurred vision (depending on how the eye is affected)
  • Corneal inflammation that may lead to scarring
  • Inflammation inside the eye and optic nerve
  • Glaucoma
  • Cataract
  • Double vision
  • Loss of sensation

Detection and Diagnosis

When the eye is affected, the eye care practitioner will perform a thorough examination with a slit lamp microscope and an ophthalmoscope. Visual acuity and intraocular pressure are also monitored. Signs of breakout on the face and body are noted.


Treatment

Herpes zoster is treated with anti-viral, pain and anti-inflammatory medications. Eye drops and ointments may be prescribed to treat ocular problems. In some cases, secondary conditions caused by herpes zoster may require surgery.

Those who are infected should avoid contact with people who may be more susceptible to contracting the disease such as: the elderly, children, pregnant women, or anyone with a compromised immune system.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Hyphaema

Hyphaema is a term used to describe bleeding in the anterior chamber (the space between the cornea and the iris) of the eye. It occurs when blood vessels in the iris bleed and leak into the clear aqueous fluid. Hyphaemas are usually characterized by pooling of blood in the anterior chamber that may be visible to the naked eye. The red blood cells of very small hyphaemas are visible only with magnification. Even the slightest amount of blood in the anterior chamber will cause decreased vision when mixed in the clear aqueous fluid.

Bleeding in the anterior chamber is most often caused by blunt trauma to the eye. It may also be associated with surgical procedures. Other causes include abnormal vessel growth in the eye and certain ocular tumors.


Signs and Symptoms

  • Decreased vision (depending on the amount of blood in the eye, vision may be reduced to hand movements and light perception only)
  • Pool of blood in the anterior chamber
  • Elevated intraocular pressure (in some cases)

Detection and Diagnosis

It is very important for the eye care practitioner to determine the cause of the hyphaema. If the hyphaema is related to an ocular injury, any detail regarding the nature of the trauma is helpful. The eye care practitioner will assess visual acuity, measure intraocular pressure, and examine the eye with a slit lamp microscope and ophthalmoscope.


Treatment

The treatment is dependent on the cause and severity of the hyphaema. Frequently, the blood is reabsorbed over a period of days to weeks. During this time, the eye care practitioner will carefully monitor the intraocular pressure for signs of the blood preventing normal flow of the aqueous through the eye's angle structures. If the eye pressure becomes elevated, eye drops may be prescribed to control it.The pupils are also evaluated to rule out damage to the iris.

In some cases, a procedure is performed to irrigate the blood from the anterior chamber to prevent secondary complications such as glaucoma and blood stains on the cornea.

Patients with significant hyphaemas must rest and avoid strenuous activity to allow the blood to reabsorb.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Iritis

Iritis is an inflammatory problem of the iris, the coloured part of the eye. It often occurs for unknown reasons, but it may be linked to certain diseases affecting the body, infections, previous eye surgery, or injury.

Iritis may affect one or both eyes. It is sometimes a chronic, recurring condition.


Signs and Symptoms

  • Red eye
  • Light sensitivity
  • Pain that may range from aching or soreness to intense discomfort
  • Small pupil
  • Tearing

Detection and Diagnosis

The eye care practitioner can detect iritis during an examination of the eye with a slit lamp microscope. Among other things, the eye care practitioner will look for microscopic white cells floating inside the eye which are a sign of inflammation. The eye care practitioner will also carefully examine inside the eye to determine if other parts of the eye are involved.


Treatment

Steroids and anti-inflammatory drops are prescribed to reduce inflammation in the eye. Dilating drops also make the eye more comfortable by relaxing the muscle that constricts the pupil.

Iritis must be treated to avoid permanent problems such as scarring inside the eye.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Keratoconus


keratoconusKeratoconus is a degenerative disease of the cornea that causes it to gradually thin and bulge into a cone-like shape. This shape prevents light from focusing precisely on the macula. As the disease progresses, the cone becomes more pronounced, causing vision to become blurred and distorted. Because of the cornea's irregular shape, patients with keratoconus are usually very nearsighted and have a high degree of astigmatism that is not correctable with glasses.

Keratoconus is sometimes an inherited problem that usually occurs in both eyes.


Signs and Symptoms

  • Nearsightedness
  • Astigmatism
  • Blurred vision - even when wearing glasses and contact lenses
  • Glare at night
  • Light sensitivity
  • Frequent prescription changes in glasses and contact lenses
  • Eye rubbing

Detection and Diagnosis

Keratoconus is usually diagnosed when patients reach their 20's. For some, it may advance over several decades, for others, the progression may reach a certain point and stop.

Keratoconus is not usually visible to the naked eye until the later stages of the disease. In severe cases, the cone shape is visible to an observer when the patient looks down while the upper lid is lifted. When looking down, the lower lid is no longer shaped like an arc, but bows outward around the pointed cornea. This is called Munson's sign.

Special corneal testing called topography provides the eye care practitioner with detail about the cornea's shape and is used to detect and monitor the progression of the disease. A pachymeter may also be used to measure the thickness of the cornea.


Treatment

The first line of treatment for patients with keratoconus is to fit rigid gas permeable (RGP) contact lenses. Because this type of contact lens is not flexible, it creates a smooth, evenly shaped surface to see through. However, because of the cornea's irregular shape, these lenses can be very challenging to fit. This process often requires a great deal of time and patience.

When vision deteriorates to the point that contact lenses no longer provide satisfactory vision, corneal transplant surgery may be necessary to replace the diseased cornea with a healthy one.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Macular Degeneration

Age-related macular degeneration (ARMD) is a degenerative condition of the macula (the central retina). It is one of the most common causes of vision loss in the over 50's, and its prevalence increases with age. AMD is caused by hardening of the arteries that nourish the retina. This deprives the sensitive retinal tissue of oxygen and nutrients that it needs to function and thrive. As a result, the central vision deteriorates.

macd effects
This example demonstrates what a patient with advanced macular degeneration sees.

Macular degeneration varies widely in severity. In the worst cases, it causes a complete loss of central vision, making reading or driving impossible. For others, it may only cause slight distortion. Fortunately, macular degeneration does not cause total blindness since it does not affect the peripheral vision.

What is the difference between wet and dry macular degeneration?

AMD is classified as either wet or dry. About 10% of patients who suffer from macular degeneration have wet AMD. This type occurs when new vessels form to improve the blood supply to oxygen-deprived retinal tissue. However, the new vessels are very delicate and break easily, causing bleeding and damage to surrounding tissue.

macd wet macd dry

Patients with wet macular degeneration develop new blood vessels under the retina. This causes haemorrhage, swelling, and scar tissue but it can be treated with laser in some cases.

Dry maculardegeneration,
although more common, typically results in a less severe, more gradual loss of vision.

The dry type is much more common and is characterized by drusen and loss of pigment in the retina. Drusen are small, yellowish deposits that form within the layers of the retina.

What causes macular degeneration?

Macular degeneration may be caused by variety of factors. Genetics, age, nutrition, smoking, and sunlight exposure may all play a role.


Signs and Symptoms

  • Loss of central vision. This may be gradual for those with the dry type. Patients with the wet type may experience a sudden decrease of the central vision.
  • Difficulty reading or performing tasks that require the ability to see detail
  • Distorted vision (Straight lines such as a doorway or the edge of a window may appear wavy or bent.)

Treatment

There is no proven medical therapy for dry macular degeneration. In selected cases of wet macular degeneration, laser photocoagulation is effective for sealing leaking or bleeding vessels. Unfortunately, laser photocoagulation usually does not restore lost vision, but it may prevent further loss. Early diagnosis is critical for successful treatment of wet macular degeneration.Patients can help the eye care practitioner detect early changes by monitoring vision at home with an Amsler grid.


Nutrition and macular degeneration

Several recent studies have indicated a strong link between nutrition and the development of macular degeneration. It has been scientifically demonstrated that people with diets high in fruits and vegetables (especially leafy green vegetables) have a lower incidence of macular degeneration. More studies are needed to determine if nutritional supplements can prevent progression in patients with existing disease.


Tips for AMD patients

If you've been diagnosed with AMD, making a few simple lifestyle changes could have a positive impact on the health of your retina.

  • Monitor your vision daily with an Amsler grid. By checking your vision regularly, changes that may require treatment can be detected early.
  • Take a multi-vitamin with zinc. (check with your eye care practitioner for a recommendation). Antioxidants, along with zinc andlutein are essential nutrients, all found in the retina. It is believed that people with AMD may be deficient in these nutrients.
  • Incorporate dark leafy green vegetables into your diet. These include spinach, collard greens, kale and turnip greens.
  • Always protect your eyes with sunglasses that have UV protection. Ultraviolet rays are believed to cause damage to the pigment cells in the retina.
  • Quit smoking. Smoking impairs the body's circulation, decreasing the efficiency of the retinal blood vessels.
  • Exercise regularly. Cardiovascular exercise improves the body's overall health and increases the efficiency of the circulatory system.

These are a few tips to make reading easier:

  • Use a halogen light. These have less glare and disperse the light better than standard light bulbs.

  • Shine the light directly on your reading material. This improves the contrast and makes the print easier to see.

  • Use a hand-held magnifier. A magnifier can increase the print size dramatically.

  • Try large-print or audio books. Most libraries and bookstores have special sections reserved for these books.

  • Consult a low vision specialist. These professionals are specially trained to help visually impaired patients improve their quality of life. After a personalized consultation, they can recommend appropriate magnifiers, reading aids, practical tips, and many resources.

Amsler Grid

amsler

  • Use a bright reading light
  • Wear your reading glasses if appropriate
  • Hold the chart approximately 14-16 inches from your eye
  • Cover one eye
  • Look at center dot
  • Note irregularities (wavy, size, gray, fuzzy)
  • Repeat the test with your other eye
  • Contact your eye care practitioner if you see any irregularities or notice any changes

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Macular Hole


macular holeMacular hole is a problem that affects the very central portion of the retina. It happens for a variety of reasons such as: eye injuries, certain diseases, and inflammation inside the eye. However, the most common cause is related to the normal aging process.

The vitreous gel inside the eye is firmly attached to the macula. With age, the vitreous becomes thinner and separates from the retina. Sometimes this creates traction on the macula, causing a hole to form.

Macular holes often begin gradually and affect central vision depending on the severity and extent of the problem. Partial holes only affect part of the macular layers, causing wavy, distorted, blurred vision. Patients with full-thickness macular holes experience a complete loss of central vision.


Signs and Symptoms

The severity of the symptoms is dependent on whether the hole is partial or full-thickness.

  • Blurred central vision
  • Distorted, "wavy" vision
  • Difficulty reading or performing tasks that require seeing detail
  • Gray area in central vision
  • Central blind spot

Detection and Diagnosis

Visual acuity testing, Amsler grid, and ophthalmoscopy are all performed to evaluate the macula's health and function. The retina specialist may also order photographs of the macula prior to performing surgery to repair the hole.


Treatment

Some macular holes seal spontaneously and require no treatment. In many cases, surgery is necessary to close the hole and restore useful vision.

Macular holes are repaired with surgery. During the operation, the surgeon first gently removes the vitreous gel with a procedure called vitrectomy. This eliminates any traction on the macula. A gas bubble is injected in the eye to place gentle pressure on the macula and help the hole to seal. In many cases, patients enjoy functional vision after the bubble has dissipated and the eye has healed.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Naevus

irislesionnevus

A naevus is typically a flat, benign, pigmented area that may appear inside the eye or on its surface. Naevae commonly appear on the choroid (the layer just behind the

retina), the iris, and the conjunctiva. Naevae are similar to freckles, and don't typically change or grow.


Signs and Symptoms

  • Brownish, freckle-like spot
  • Usually flat

Detection and Diagnosis

Naevae of the conjunctiva or iris can be detected with a slit lamp microscope. If the naevus occurs within the eye, it is evaluated with an ophthalmoscope.


Treatment

Naevae are usually harmless, but it's always wise to monitor them for changes. This can be done with photos and sometimes ultrasound. The eye care practitioner will document the size, shape and whether the naevus is elevated. In rare cases, the naevus must be biopsied and examined for melanoma (cancer) cells.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Neovascularization

New (neo) blood vessel growth (vascularization) on the cornea. Often caused by contact lens complications. The blood vessels in this photograph (arrows) are abnormal in size, shape, and location, indicating corneal neovascularization.

cornealneo

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Neovascularization of the Optic Nerve Head

New blood vessel growth on the optic nerve head. In this photograph, abnormal new blood vessels (arrows) can be seen growing off of the disc and into the vitreous (the clear gel inside the eye). This condition is common in patients with proliferative diabetic retinopathy.

nvd

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Ocular Rosacea

Ocular rosacea is associated with a chronic skin condition known as acne rosacea. The problem usually affects those with light skin, and is characterized by redness and bumps concentrated on the forehead, nose and cheeks. One of the earliest symptoms of rosacea (often experienced during puberty) is facial flushing brought on by changes in body temperature, emotion, or hot drinks. Eventually, the skin may become chronically red, irritated and inflamed.

Approximately 60% of patients with rosacea develop related problems affecting the eye (ocular rosacea). Patients with ocular rosacea most commonly experience irritation of the lids and eye, occurring when the oil-producing glands of the lids become obstructed. Styes, blepharitis, episcleritis, and chronically red eyes are also typical conditions. Ocular rosacea may also affect the cornea, causing neovascularization (abnormal blood vessel growth), infections, and occasionally ulcers.


Signs and Symptoms

Acne Rosacea

  • Red, flushed skin
  • Breakouts or papules concentrated on the nose, forehead, and cheeks
  • Facial flushing after drinking alcohol, eating hot or spicy foods, or events that increase body temperature
  • Dry, flaking skin

Ocular Rosacea

  • Chronically red eyes and lid margins
  • Irritated eyelids (blepharitis)
  • Styes (chalazion)
  • Dry, irritated eyes
  • Burning
  • Foreign body sensation

Detection and Diagnosis

Those with ocular rosacea are frequently under the care of a dermatologist and are referred for treatment when the patient develops related eye conditions. However, the eye care practitioner may also make the initial diagnosis with a routine eye exam and evaluation of the skin.


Treatment

Patients with this condition should avoid hot drinks, spicy foods, alcohol, or activities that cause the body temperature to become elevated. Care should be taken to protect the skin from ultraviolet light exposure by using sunscreen with a high SPF factor and wearing hats and sunglasses when outdoors.

Controlling skin inflammation may give marked relief of the eye conditions. Because of this, the eye care practitioner and dermatologist often work together to treat the problem. Eye-related symptoms can often be relieved with warm (not hot) compresses on the lids, eyelid scrubs and artificial tears. Topical and/or oral antibiotics may also be prescribed to reduce symptoms.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Optic Neuritis

Optic neuritis refers to swelling or inflammation of the optic nerve. It is often associated with diseases causing demyelination (a loss of the protective myelin layer of the the nerve) of the optic nerve, but sometimes the cause is unknown. Multiple sclerosis (MS) is the disease most often associated with optic neuritis. It is not uncommon to have an episode of optic neuritis prior to being diagnosed with MS. In fact, optic neuritis is often the initial sign of MS.

Most patients with optic neuritis experience a sudden onset of decreased vision along with pain and soreness when moving the eye. Optic neuritis usually affects only one eye and may be a recurring problem with certain diseases such as MS.


Signs and Symptoms

The following symptoms of optic neuritis may not occur in all cases; however, they are the most common problems associated with the condition.

  • Pain with eye movement (more than 90% of patients)
  • Tender, sore eye
  • Mild to severe decrease in central vision
  • Dull, dim vision
  • Reduced color perception
  • Decreased peripheral vision
  • Central blind spot
  • Fever
  • Headache
  • Nausea
  • Decreased vision following exercise, hot bath or shower (activities that elevate body temperature)

Detection and Diagnosis

The eye care practitioner takes several factors into consideration when diagnosing optic neuritis. The problem may not always be readily apparent by examining the optic nerve, so special attention is paid to the patient's symptoms and other tests. Pain with eye movement is a hallmark symptom of optic neuritis. The eye care practitioner may evaluate the pupils' reaction to light and order tests such as: visual field, color vision, and imaging of the brain (MRI).


Treatment

Since the Optic Neuritis Treatment Trial (ONTT), physicians have discovered that treating patients with intravenous steroid medication (but not oral steroids) reduces the risk of developing MS later on. This finding is very significant since approximately 50% of those who experience an initial occurrence of optic neuritis will develop MS. While this treatment has little if any impact on vision, it is important for overall health.

Optic neuritis characteristically improves over a period of days to weeks. For some, a complete recovery may take months.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Pinguecula

A pinguecula (pin gwe' cue la) is a benign, yellowish growth that forms on the conjunctiva. They usually grow near the cornea on the nasal side. Pingueculae (plural form of pinguecula) are thought to be caused by ultraviolet light and are most common among people who spend a great deal of time outdoors.

This growth does not affect vision, but may cause irritation if it becomes elevated. In rare cases, the pinguecula may gradually extend over the cornea, forming a pterygium.


Signs and Symptoms

Pingueculae are harmless growths and rarely cause symptoms.

  • Yellowish, raised area on the conjunctiva
  • Irritation and scratchiness
  • Dry eye
  • Occasional inflammation of the conjunctiva
  • Redness if the area becomes irritated

Detection and Diagnosis

Pingueculae can often be seen with the naked eye; however, the eye care practitioner diagnoses the growth with a careful examination with a slit lamp microscope.


Treatment

Because of their benign nature, pingueculae rarely require treatment. Occasionally, the growth may become inflamed, causing irritation and dryness. The eye care practitioner may prescribe artificial tears for lubrication and mild anti-inflammatory medication to reduce swelling.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Pterygium

(pronounced ter ig ee um)

pterygium

Pterygium is a raised, wedge-shaped growth of the conjunctiva. It is most common among those who live in tropical climates or spend a lot of time in the sun. Symptoms may include irritation, redness, and tearing. Pterygia are nourished by tiny capillaries that supply blood to the tissue. For some, the growth remains dormant; however, in other cases it grows over the central cornea and affects the vision. As the pterygium develops, it may alter the shape of the cornea, causing astigmatism. Before the pterygium invades the central cornea, it should be removed surgically.

Since pterygia are most commonly caused by sun exposure, protecting the eyes from sun, dust and wind is recommended. Instilling artificial tears liberally is also helpful to decrease irritation. In some cases, steroid drops are prescribed to reduce inflammation.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Ptosis

Ptosis (pronounced toe' sis), or drooping of the upper eyelid, may occur for several reasons such as: disease, injury, birth defect, previous eye surgery and age. In most cases, it is caused by either a weakness of the levator muscle (muscle that raises the lid), or a problem with the nerve that sends messages to the muscle.

Children born with ptosis may require surgical correction of the lid if it covers the pupil. In some cases, it may be associated with a crossed or misaligned eye (strabismus). Left untreated, ptosis may prevent vision from developing properly, resulting in amblyopia, or lazy eye.

Patients with ptosis often have difficult blinking, which may lead to irritation, infection and eyestrain. If a sudden and obvious lid droop is developed, an eye care practitioner should be consulted immediately.


Signs and Symptoms

The causes of ptosis are quite diverse. The symptoms are dependent on the underlying problem and may include:

  • Drooping lid (may affect one or both eyes)
  • Irritation
  • Difficulty closing the eye completely
  • Eye fatigue from straining to keep eye(s) open
  • Children may tilt head backward in order to lift the lid
  • Crossed or misaligned eye
  • Double vision

Detection and Diagnosis

When examining a patient with a drooping lid, one of the first concerns is to determine the underlying cause. The ophthalmic surgeon will measure the height of the eyelid, strength of the eyelid muscles, and evaluate eye movements and alignment. Children may require additional vision testing for amblyopia.


Treatment

Ptosis does not usually improve with time, and nearly always requires corrective surgery by an ophthalmologist specializing in plastic and reconstructive surgery. In most cases, surgery is performed to strengthen or tighten the levator muscle and lift the eyelid. If the levator muscle is especially weak, the lid and eyebrow may be lifted. Ptosis surgery can usually be performed with local anaesthesia except with young children.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Recurrent Corneal Erosion

Recurrent corneal erosion is a condition affecting the outermost layer of corneal cells called the epithelium. The problem is caused when the bottom layer of epithelial cells adheres poorly to the cornea, causing them to slough off easily. The pain and discomfort is often quite intense, and similar to a corneal abrasion. There is usually an underlying disorder that causes recurrent corneal erosions to occur. The most common are: previous corneal injury (corneal abrasion), corneal dystrophy (Map Dot Fingerprint Dystrophy), or corneal disease resulting in recurrent breakdown of the epithelial cells.

Upon awakening, patients often experience severe pain, blurred vision, and light sensitivity when the eyelid pulls the loosened epithelial cells off the cornea. After the cornea heals, the problem recurs as the name implies unless the condition is treated. Recurrent corneal erosion may affect one or both eyes, depending on the underlying cause.


Signs and Symptoms

  • Severe pain (especially after awakening)
  • Blurred vision
  • Foreign body sensation
  • Dryness and irritation
  • Tearing
  • Red eye
  • Light sensitivity

Detection and Diagnosis

Using a slit lamp microscope, the eye care practitioner examines the corneal layers under high magnification. Eye drops containing green dye called fluorescein are usually instilled to stain the areas of missing epithelium, allowing the eye care practitioner to evaluate the size and depth of the erosion.


Treatment

Salt solution drops or ointment are usually prescribed as the first line of treatment. This medication helps the epithelium to adhere better to Bowman's layer of the cornea. Artificial tears are also recommended to keep the cornea moist.

Those with underlying corneal dystrophy may require additional treatment. This usually includes an in-office procedure where the epithelium is either gently removed, or microscopic "spot welds" are made on the cornea to encourage the epithelium to bond securely to Bowman's layer underneath.

Patients who continue to suffer from recurrent corneal erosions despite the treatments described, may benefit from phototherapeutic keratectomy (PTK). This involves removal of the superficial layer of corneal cells using the Excimer laser to encourage proper healing.


Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.

Retinal Tear and Detachment

Retinal Tear

Retinal tears commonly occur when there is traction on the retina by the vitreous gel inside the eye. In a child's eye, the vitreous has an egg-white consistency and is firmly attached to certain areas of the retina. Over time, the vitreous gradually becomes thinner, more liquid and separates from the retina. This is known as a posterior vitreous detachment (PVD).

PVDs are typically harmless and cause floaters in the eye; but in some cases, the traction on the retina may create a tear. Retinal tears frequently lead to detachments as fluids seep underneath the retina, causing it to separate and detach.

Retinal Detachmentretinal detachment

A retinal detachment occurs when the retina's sensory and pigment layers separate. Because it can cause devastating damage to the vision if left untreated, retinal detachment is considered an ocular emergency that requires immediate medical attention and surgery. It is a problem that occurs most frequently in the middle-aged and elderly.

There are three types of retinal detachments. The most common type occurs when there is a break in the sensory layer of the retina, and fluid seeps underneath, causing the layers of the retina to separate. Those who are very nearsighted, have undergone eye surgery, or have experienced a serious eye injury are at greater risk for this type of detachment. Nearsighted people are more susceptible because their eyes are longer than average from front to back, causing the retina to be thinner and more fragile.

The second most common type occurs when strands of vitreous or scar tissue create traction on the retina, pulling it loose. Patients with diabetes are more likely to experience this type.

The third type happens when fluid collects underneath the layers of the retina, causing it to separate from the back wall of the eye. This type usually occurs in conjunction with another disease affecting the eye that causes swelling or bleeding.


Signs and Symptoms

  • Light flashes
  • "Wavy," or "watery" vision
  • Veil or curtain obstructing vision
  • Shower of floaters that resemble spots, bugs, or spider webs
  • Sudden decrease of vision

Detection and Diagnosis

Retinal detachments are usually found because the patient calls the eye care practitioner's office with a symptom listed above. It is critical that these problems are reported early, because early treatment can greatly improve the chance of restoring vision.

The eye care practitioner makes the diagnosis of a retinal detachment after thoroughly examining the retina with ophthalmoscopy. The retinal surgeon's first concern is to determine whether the macula (the center of the retina) is attached. This is critical because the macula is responsible for the central vision. Whether or not the macula is attached determines the type of corrective surgery required and the patient's chances of having functional vision after the operation.

Ultrasound imaging of the eye is also very useful for the retinal surgeon to see additional detail of the condition of the retina from several angles.


Treatment

There are a number of ways to treat retinal detachment. The appropriate treatment depends on the type, severity and location of the detachment.

Pneumatic retinopexy is one type of procedure to reattach the retina. After numbing the eye with a local anaesthesia, the surgeon injects a small gas bubble into the vitreous cavity. The bubble presses against the retina, flattening it against the back wall of the eye. Since the gas rises, this treatment is most effective for detachments located in the upper portion of the eye. In order to manipulate the bubble into the ideal location, the surgeon may ask the patient to keep his or her head in a specific position.

The gas bubble slowly absorbs over the next 1-2 weeks. At that time, an additional procedure is usually performed to "tack down" the retina. This can be done either with cryotherapy, a procedure that uses nitrous oxide to freeze the retina, sealing it in place, or with laser. Local anaesthesia is used for both procedures.

Some types of retinal detachments, because of their location or size, are best treated with a procedure called a scleral buckle. With this technique, a tiny sponge or band made of silicone is attached to the outside of the eye, pressing inward and holding the retina in position. After removing the vitreous gel from the eye with a procedure called a vitrectomy, the surgeon usually seals a few areas of the retina into position with laser or cryotherapy. The scleral buckle is not visible and remains permanently attached to the eye. This technique of reattaching the retina may elongate the eye, causing nearsightedness.

In rare cases where other types of retinal detachment surgeries are either inappropriate or unsuccessful, silicone oil may be used to reattach the retina. The vitreous gel is removed and replaced with silicone oil, which presses the retina into place. While the oil is inside the eye, the vision is extremely poor. After the retina has resealed itself against the back of the eye, a second procedure may be performed to remove the oil.


What you can do...

Early detection is the key in successfully treating retinal detachments and tears. Awareness of the quality of your vision in each eye is extremely important, especially if you are in a higher-risk group such as those who are nearsighted or diabetic. Compare the vision of your eyes daily by looking straight ahead and covering one eye and then the other.

Notify your doctor immediately if you notice any of the following:

  • An obstruction of your peripheral vision (veil, shadow, or curtain)
  • Sudden shower of floaters
  • Light flashes

Illustrations by Mark Erickson
With acknowledgement to St. Lukes Eye Hospital.