Vision Health: Conditions, Disorders & Treatments – RETINAL DISEASES There are a number of diseases that affect the retina, the layer of nerve cells lining the back of the eye to sense light and create impulses to the brain where they are recognized as an image.

Retinal Testing – Optical Coherence Tomography (OCT) Optical coherence tomography (OCT) is a retinal scan used to study the anatomy of the retina in fine detail. OCT testing requires dilation of the pupils but does not require a needle in the arm and does not involve touching the eye. A healthy retina is only ¼ of a millimeter thick, but it contains multiple layers of specialized cells. One layer converts light into nerve signals, another processes the nerve impulses, while another transmits these processed impulses to the brain where they are interpreted. OCT testing is like having an optical biopsy of the retina; it provides excellent visualization of these layers of the retina, and aids greatly in the diagnosis and treatment of retinal disorders like AMD. Not every patient needs an OCT test. In some parts of Canada OCT testing performed for the evaluation of retinal disease is covered by provincial or territorial health plans.

Retinal Testing – Fluorescein Angiography Fluorescein angiography, a clinical test to look at blood circulation inside the back of the eye, aids in the diagnosis of retinal conditions associated with diabetes, age-related macular degeneration, and other eye abnormalities. The test can also help follow the course of a disease and monitor its treatment. It may be repeated on multiple occasions with no harm to the eye or body. Fluorescein is an orange-red dye that is injected into a vein in the arm. The dye travels through the body to the blood vessels in the retina, the light-sensitive nerve layer at the back of the eye.

Fluorescein angiography is performed to evaluate the blood vessels in eyes with macular or retinal disease. A series of pictures of your macula and retina are then taken over approximately 15-20 minutes. Most patients tolerate this test very well without any side effects. Some patients feel nauseated for a few minutes. The technique uses regular photographic film, or, more commonly, is performed with digital equipment. No X-rays are involved. If there are abnormal blood vessels, the dye leaks into the retina or stains the blood vessels. Damage to the lining of the retina or atypical new blood vessels may be revealed as well. These abnormalities are determined by a careful interpretation of the photographs by your eye surgeon (ophthalmologist). The dye can discolor skin and urine until it is removed from the body by the kidneys. There is little risk in having fluorescein angiography, though some people may have mild allergic reactions to the dye. Severe allergic reactions have been reported but only very rarely. Being allergic to X-ray dyes with iodine does not mean you will be allergic to fluorescein. Occasionally, some of the dye leaks out of the vein at the injection site, causing a slight burning sensation that usually goes away quickly.

Age-Related Macular Degeneration (AMD) Age-related macular degeneration (AMD) is one of the most common causes of poor vision after age 60. AMD is a deterioration or breakdown of the macula. The macula is a small area at the center of the retina in the back of the eye that allows us to see fine details clearly and perform activities such as reading and driving. The visual symptoms of AMD involve loss of central vision. While peripheral (side) vision is unaffected, with AMD, one loses the sharp, straight-ahead vision necessary for driving, reading, recognizing faces, and looking at detail. Early AMD changes can be detected at home with the use of an Amsler grid. Patients should test one eye at a time, covering the other eye and looking at the grid. If the lines of the grid appear wavy, distorted or missing, the test is abnormal and the finding should be investigated by an optometrist or ophthalmologist. Although the specific cause is unknown, AMD seems to be part of aging.

While age is the most significant risk factor for developing AMD, heredity, blue eyes, high blood pressure, cardiovascular disease, and smoking have also been identified as risk factors. AMD accounts for 90% of new cases of legal blindness in Canada. Nine out of 10 people who have AMD have atrophic or “dry” AMD, which results in thinning of the macula. Dry AMD takes many years to develop. A specific vitamin regimen based on the AREDS (Age=Related Eye Disease Study) has been shown to slow progression of dry AMD.

“Wet” AMD Exudative or “wet” AMD is less common (occurring in one out of 10 people with AMD) but is more serious. In the wet form of AMD, abnormal blood vessels may grow in a layer beneath the retina, leaking fluid and blood and creating distortion or a large blind spot in the center of your vision. If the blood vessels are not growing directly beneath the macula, laser surgery is usually the treatment of choice. The procedure usually does not improve vision but tries to prevent further loss of vision. For those patients with wet AMD whose blood vessels are growing directly under the center of the macula, intravitreal injections with an anti-vascular endothelial growth factor agent called Lucentis (ranibizumab) has been shown to preserve vision in 95% of patients and restore or partially restore it in 40% of patients. A procedure called photodynamic therapy (PDT), is also sometimes used. Intravitreal injections of other medications can also be used in some cases. Promising AMD research is being done on many fronts. In the meantime, high-intensity reading lamps, magnifiers, and other low vision aids help people with AMD to maximize their visual abilities.

Wet AMD Treatments Because the “wet” type of age-related macular degeneration (AMD) can lead to rapid vision loss, treating wet AMD is time-sensitive, especially as delays can result in poorer visual outcomes in a matter of a week or less. There are currently two main treatments available for wet AMD:

Anti-VEGF Injections The best treatment for wet-AMD is an injection with a type of drug called an anti-vascular endothelial growth factor (anti-VEGF). The anti-VEGF drug designed specifically for the eye is called Lucentis (ranibizumab). Lucentis works by inhibiting the growth of new blood vessels such as those found in “wet” AMD, and by shrinking existing leaky vessels. Research has also shown the drug to be beneficial for restoring/preserving the vision of patients with other eye problems with macular thickening. Treatment with Lucentis involves injecting the drug into the eye. About 40% of AMD patients experience visual improvements with these injections, with some patients gaining significant amounts of vision. Complications with this procedure are rare, but include retinal tear (1%) and infection (0.1%). Lucentis is the preferred anti-VEGF drug in the treatment of “wet” AMD, as it has been developed and tested and proven safe and effective for use in the eye specifically. Lucentis is covered by OHIP for patients who have developed wet AMD within the past three months and who have not had photodynamic therapy. Some patients with other retinal diseases or those under the age of 65 may benefit from Lucentis but do not qualify for OHIP coverage. For these patients, your eye surgeon may use another anti-VEGF drug named Avastin (bevacizumab) that is similar to Lucentis in its effect but much less expensive. Avastin injections are not covered by OHIP, and the cost of this drug will vary between offices, but the Canadian Ophthalmological Society recommends that charges for the use of this drug are not to exceed $277. With either drug patients require an average of six to nine treatments per year, at four to six week intervals.

Photodynamic Therapy (PDT) The second treatment typically used with the “wet” form of age-related macular degeneration (AMD) is called photodynamic therapy (PDT). PDT involves injecting a drug (visudyne) into the bloodstream and then activating the drug in the macula using a laser.

The drug works to seal up the leaking blood vessels in the macula. Visudyne makes patients light sensitive for 48 hours, so special precautions must be taken to stay out of bright light following treatment with PDT. PDT prevents further loss of vision from AMD in 2/3 of patients, but only 17% of patients see visual improvement with PDT. About 4% of patients have a decrease in vision after PDT; for most this loss is temporary. As Lucentis is so much more effective than PDT, most ophthalmologists choose Lucentis as a treatment and only opt to use PDT in patients who:

1) are not covered for Lucentis injections and cannot afford Avastin, or 2) cannot tolerate the idea of an injection in the eye, or 3) who have not had success with Lucentis treatments.

Following patients being treated for AMD and other retinal conditions requires special testing to monitor the effects of treatment. The two types of special testing are fluorescein angiography and optical coherence tomography.

Diabetic Retinopathy If you have diabetes mellitus, your body does not use and store glucose properly. Over time, diabetes can damage blood vessels in the retina, the nerve layer at the back of the eye that senses light and helps to send images to the brain. The damage to retinal vessels is referred to as diabetic retinopathy.

Nonproliferative Diabetic Retinopathy (NPDR) Nonproliferative diabetic retinopathy (NPDR), commonly known as ‘background retinopathy’, is an early stage of diabetic retinopathy. In this stage, tiny blood vessels within the retina leak blood or fluid. The leaking fluid causes the retina to swell or to form deposits called exudates. Many people with diabetes have mild NPDR, which usually does not affect their vision. When vision is affected, it is the result of macular edema or macular ischemia, or both.

Macular Edema & Ischemia Macular edema is swelling or thickening of the macula, a small area in the centre of the retina that allows us to see fine details clearly.

The swelling is caused by fluid leaking from retinal blood vessels. It is the most common cause of visual loss in diabetes. Vision loss may be mild to severe, but even in the worst cases, peripheral (side) vision continues to function. Laser treatment can be used to help control vision loss from macular edema. Newer treatments are being investigated. Macular ischemia occurs when small blood vessels (capillaries) close. Vision blurs because the macula no longer receives sufficient blood supply to work properly. Unfortunately, there are no effective treatments for macular ischemia.

Proliferative Diabetic Retinopathy Proliferative diabetic retinopathy (PDR) is a complication of diabetes caused by changes in the blood vessels of the eye. If you have diabetes, your body does not use and store sugar properly. High blood sugar levels create changes in the veins, arteries, and capillaries that carry blood throughout the body. This includes the tiny blood vessels in the retina, the light-sensitive nerve layer in the back of the eye. In PDR, the retinal blood vessels are so damaged they close off. In response, the retina grows new, fragile blood vessels. Unfortunately, these new blood vessels are abnormal and grow on the surface of the retina, so they do not resupply the retina with blood. Occasionally, these new blood vessels bleed and cause a vitreous hemorrhage. Blood in the vitreous, the clear gel-like substance that fills the inside of the eye, blocks light rays from reaching the retina. A small amount of blood will cause dark floaters, while a large hemorrhage might block all vision, leaving only light and dark perception. The new blood vessels can also cause scar tissue to grow. The scar tissue shrinks, wrinkling and pulling on the retina and distorting vision. If the pulling is severe, the macula may detach from its normal position and cause vision loss. Laser surgery may be used to shrink the abnormal blood vessels and reduce the risk of bleeding. The body will usually absorb blood from a vitreous hemorrhage, but that can take days, months, or even years. If the vitreous hemorrhage does not clear within a reasonable time, or if a retinal detachment is detected, an operation called a vitrectomy can be performed.

During a vitrectomy, the eye surgeon removes the hemorrhage and any scar tissue that has developed, and performs laser treatment to prevent new abnormal vessel growth. People with PDR sometimes have no symptoms until it is too late to treat them. The retina may be badly injured before there is any change in vision. There is considerable evidence to suggest that rigorous control of blood sugar decreases the chance of developing serious proliferative diabetic retinopathy. A medical eye examination is the only way to discover any changes inside your eye. If your ophthalmologist finds diabetic retinopathy, you may require a special test called fluorescein angiography or optical coherence tomography (OCT) to find out if you need treatment. If you have diabetes, early detection of diabetic retinopathy is the best protection against loss of vision. You can significantly lower your risk of vision loss by maintaining strict control of your blood glucose and visiting your ophthalmologist regularly. People with diabetes should schedule examinations at least once a year. Pregnant women with diabetes should schedule an appointment in their first trimester, because retinopathy can progress quickly during pregnancy. More frequent medical eye examinations may be necessary after a diagnosis of diabetic retinopathy.

Diabetic Retinopathy Treatments – Focal Laser Macular edema is treated with laser surgery. This procedure is called focal laser treatment. Your ophthalmologist places up to several hundred small laser burns in the areas of retinal leakage surrounding the macula. These burns slow the leakage of fluid and reduce the amount of fluid in the retina. The surgery is usually completed in one session, although further treatment may be needed. A patient may need focal laser surgery more than once to control the leaking fluid. Focal laser treatment stabilizes vision. In fact, focal laser treatment reduces the risk of vision loss by 50 percent. In a small number of cases, if vision is lost, it can be improved. Let your eye surgeon (ophthalmologist) know if you have vision loss. Before the laser surgery, the technician will dilate your pupil and apply drops to numb the eye. The area behind your eye also may be numbed to prevent discomfort. The lights in the laser room will be dim. As you sit facing the laser machine, your eye surgeon will hold a special lens to your eye.

During the procedure, you may see flashes of light. These flashes eventually may create a stinging sensation that can be uncomfortable. You will need someone to drive you home after surgery. Because your pupil will remain dilated for a few hours, you should bring a pair of sunglasses. For the rest of the day, your vision will probably be a little blurry. Your ophthalmologist will make arrangement to check the effects of the laser, usually within about six weeks of treatment.

Diabetic Retinopathy Treatments – Pan-Retinal Photocoagulation During the first three stages of diabetic retinopathy, no treatment is needed, unless you have macular edema. To prevent progression of diabetic retinopathy, people with diabetes should control their levels of blood sugar, blood pressure, and blood cholesterol. Proliferative retinopathy is treated with laser surgery. This procedure is called pan-retinal photocoagulation or PRP, which helps to shrink the abnormal blood vessels. Your doctor places 1,000 to 2,000 laser burns in the areas of the retina away from the macula, causing the abnormal blood vessels to shrink. Because a high number of laser burns are necessary, two or more sessions usually are required to complete treatment. Although you may notice some loss of your side vision, PRP can save the rest of your sight. PRP may slightly reduce your colour vision and night vision. PRP works better before the fragile, new blood vessels have started to bleed. That is why it is important to have regular, comprehensive dilated eye exams. Even if bleeding has started, PRP may still be possible, depending on the amount of bleeding. If the bleeding in your eye is severe, you may need a surgical procedure called a vitrectomy. During a vitrectomy, blood is removed from the center of your eye by a retinal specialist.

Diabetic Retinopathy Treatments – Anti-VEGF Drugs Certain anti-vascular endothelial growth factor (anti-VEGF) treatments are approved for a condition known as “wet” age-related macular degeneration (AMD), in which abnormal blood vessels grow underneath the retina.

These unhealthy vessels leak blood and fluid that can swell and scar the macula (the central part of the retina), and vision loss may be rapid and severe. Since anti-VEGF therapies have shown good potential for slowing vascular leakage and preventing vision loss associated with wet AMD, ophthalmologists are using them to treat other causes of macular edema. If your ophthalmologist has diagnosed you with diabetic retinopathy, retinal venous occlusion, or other conditions, you may benefit from anti-VEGF treatment if other therapies are not producing the desired results or if your ophthalmologist thinks that anti-VEGF therapy is the best first course of action. Treatment with the anti-VEGF drug is usually performed by injecting the medicine with a very fine needle into the back portion of your eye. Your ophthalmologist will clean your eye to prevent infection and will administer an anesthetic into your eye to reduce pain. Usually, patients receive multiple anti-VEGF injections over the course of many months. There is a small risk of complications with anti-VEGF treatment, usually resulting from the injection itself. However, for most people, the benefits of this treatment outweigh the small risk of complications.

Branch Retinal Artery Occlusion (BRAO) Most people know that high blood pressure and other vascular diseases pose risks to overall health, but many may not know that high blood pressure can affect vision by damaging the arteries in the eye. Branch retinal artery occlusion (BRAO) blocks the small arteries in the retina, the light-sensing nerve layer lining the back of the eye. The most common cause of BRAO is a thrombosis, the formation of a blood clot. Sometimes the blockage is caused by an embolus, a clot carried by the blood from another part of the body. Central vision is lost suddenly if the blocked retinal artery is one that nourishes the macula, the part of the retina responsible for fine, sharp vision. Following BRAO, vision can range from normal (20/20) to being barely able to detect hand movement. BRAO poses significant risks to vision. If you have had a branch retinal artery occlusion, regular visits to your ophthalmologist or optometrist are essential.

Central Retinal Artery Occlusion (CRAO) You probably know that high blood pressure and other vascular diseases pose risks to your overall health, but you may not know that they can affect your eyesight by damaging the arteries in your eye.

Central retinal artery occlusion (CRAO) usually occurs in people between the ages of 50 and 70. The most common medical problem associated with CRAO is arteriosclerosis (hardening of the arteries). Carotid artery disease is found in almost half the people with CRAO. The most common cause of CRAO is a thrombosis (an abnormal blood clot formation). CRAO can also be caused by an embolus, a clot that breaks off from another area of the body and is carried to the retina by the bloodstream. CRAO blocks the central artery in your retina, the light-sensitive nerve layer at the back of the eye. The first sign of CRAO is a sudden and painless loss of vision that leaves you barely able to count fingers or determine light from dark. Loss of vision can be permanent without immediate treatment. Irreversible retinal damage occurs after 90 minutes, but even 24 hours after symptoms begin, vision can still be saved or partially restored. The goal of emergency treatment is to restore retinal blood flow. After emergency treatment, you should have a thorough medical evaluation.

Branch Retinal Vein Occlusion (BRVO) Most people know that high blood pressure and other vascular diseases pose risks to overall health, but many may not know that high blood pressure can affect vision by damaging the veins in the eye. High blood pressure is the most common condition associated with branch retinal vein occlusion (BRVO). About 10% to 12% of the people who have BRVO also have glaucoma (high pressure in the eye). BRVO blocks small veins in the retina, the layer of light-sensing cells at the back of the eye. If the blocked retinal veins are ones that nourish the macula, the part of the retina responsible for straight-ahead vision, some central vision is lost. During the course of vein occlusion, 60% or more will have swelling of the central macular area. In about one-third of people, this macular edema will last for more than one year. BRVO causes a painless decrease in vision, resulting in misty or distorted vision. If the veins cover a large area, new abnormal vessels may grow on the retinal surface, which can bleed into the eye and cause blurred vision. There is no cure for BRVO. Finding out what caused the blockage is the first step in treatment. Your ophthalmologist (Eye M.D.) may recommend a period of observation, since hemorrhages and excess fluid may subside on their own. Depending on how damaged the veins are, laser surgery may help reduce the swelling and improve vision.

Laser surgery may also shrink abnormal new blood vessels that can grow and that are at risk of bleeding. Newer injectable medicines like anti-VEGFs have shown promising results for treating BRVO. If you have had a branch retinal vein occlusion, regular visits to your ophthalmologist or optometrist are essential to protect vision.

Central Retinal Vein Occlusion (CRVO) Central retinal vein occlusion (CRVO) blocks the main vein in the retina, the light-sensitive nerve layer at the back of the eye. The blockage causes the walls of the vein to leak blood and excess fluid into the retina. When this fluid collects in the macula (the area of the retina responsible for central vision), vision becomes blurry. “Floaters” in your vision are another symptom of CRVO. When retinal blood vessels are not working properly, the retina grows new fragile vessels that can bleed into the vitreous, the fluid that fills the center of the eye. Blood in the vitreous clumps and is seen as tiny dark spots, or floaters, in the field of vision. In severe cases of CRVO, the blocked vein causes painful pressure in the eye. Retinal vein occlusions commonly occur with glaucoma, diabetes, age-related vascular disease, high blood pressure, and blood disorders. The first step of treatment is finding what is causing the vein blockage. There is no cure for CRVO. Your ophthalmologist may recommend a period of observation, since hemorrhages and excess fluid often subside on their own. Laser surgery may be effective in preventing further bleeding into the vitreous or for treating glaucoma, but it cannot remove a hemorrhage or cure glaucoma once it is present. New experimental treatments are now under investigation. Anti-VEGF injections have shown promising results in the treatment of CRVO.

Central Serious Retinopathy (CSR) Central serous retinopathy (CSR) is a small, round, shallow swelling that develops on the retina, the light-sensitive nerve layer that lines the back of the eye.

Although the swelling reduces or distorts vision, the effects are usually temporary. Vision generally recovers on its own within a few months. In the initial stages of CSR, vision may suddenly become blurred and dim. If the macula (the area of the retina responsible for central vision) is not affected, there may be no obvious symptoms. CSR typically affects adults between the ages of 20 and 50. People with CSR often find that their retinal swelling resolves without treatment and their original vision returns within six months of the onset of symptoms. Some people with frequent episodes may have some permanent vision loss. Recurrences are common and can affect 20% to 50% of people with CSR. While the cause of CSR is unknown, it seems to occur at times of personal or work-related stress. As CSR usually resolves on its own, no treatment may be necessary. Sometimes laser surgery can reduce the swelling sooner, but the final visual outcome is usually about the same. If retinal swelling persists for more than three or four months, or if an examination reveals early retinal degeneration, laser surgery may be helpful.

Epiretinal Membrane The retina is a layer of light-sensing cells lining the back of your eye. As light rays enter your eye, the retina converts the rays into signals that are sent through the optic nerve to your brain, where they are recognized as images. The macula is the small area at the center of your retina that allows you to see fine details. The macula normally lies flat against the back of the eye, like film lining the back of a camera. As you age, the clear, gel-like substance that fills the middle of your eye begins to shrink and pull away from the retina. In some cases, a thin “scar tissue” or membrane can grow on the surface of the macula. When wrinkles, creases, or bulges form on the macula due to this scar tissue, this is known as an epiretinal membrane or macular pucker. Damage to your macula causes blurred central vision, making it difficult to perform tasks such as reading small print or threading a needle. Peripheral (side) vision is not affected. Symptoms, which can be mild or severe and affect one or both eyes, may include:

blurred detail vision;

distorted or wavy vision;

gray or cloudy area in central vision; and

blind spot in central vision.

Your ophthalmologist will detect an epiretinal membrane by examination and OCT testing. If your symptoms are mild, no treatment may be necessary. Updating your eyeglass prescription or wearing bifocals may improve your vision sufficiently. If you have more severe symptoms that interfere with your daily routine, your ophthalmologist may recommend vitrectomy surgery to peel and remove the abnormal scar tissue. During this outpatient procedure, a retinal specialist uses tiny instruments to remove the wrinkled tissue. Vision often improves. Be sure to discuss your options. If surgery is recommended, you should be aware that as with any surgical procedure, rare complications can occur, including infection, bleeding, retinal detachment, recurrence of the epiretinal membrane, and earlier onset of cataract.

Retinal Tear/Detachment A retinal detachment is a very serious problem that usually causes blindness unless treated. The appearance of flashing lights, floating objects, or a gray curtain moving across the field of vision are all indications of a retinal detachment. If any of these occur, see an ophthalmologist right away. As one gets older, the vitreous (the clear, gel-like substance that fills the inside of the eye) tends to shrink slightly and take on a more watery consistency. Sometimes as the vitreous shrinks, it exerts enough force on the retina to make it tear. Retinal tears can lead to a retinal detachment. Fluid vitreous, passing through the tear, lifts the retina off the back of the eye like wallpaper peeling off a wall. Laser surgery or cryotherapy (freezing) are often used to seal retinal tears and prevent detachment. Most retinal tears can be repaired by general ophthalmologists, but more challenging repairs will require the skills of a retinal specialist. If the retina is detached, it must be reattached by a retinal specialist before sealing the retinal tear. There are three ways to repair retinal detachments:

1) Pneumatic retinopexy involves injecting a special gas bubble into the eye that pushes on the retina to seal the tear.

2) The scleral buckle procedure requires the fluid to be drained from under the retina before a flexible piece of silicone is sewn on the outer eye wall to give support to the tear while it heals.

3) Vitrectomy surgery removes the vitreous gel from the eye, replacing it with a gas bubble, which

is slowly replaced by the body’s fluids.

All of these procedures are only performed by ophthalmologists who are retinal specialists.

Myopic Degeneration Myopic degeneration is a condition characterized by progressive stretching of the eye that damages the retina, the layer of light-sensitive cells that lines the back of the eye. People with severe nearsightedness (high myopia) are at greater risk for myopic degeneration. Myopic degeneration commonly occurs during young adulthood and can lead to a gradual decrease in central vision. Vision can decrease more abruptly in a small percentage of patients. Although central vision may be lost, side (peripheral) vision usually remains unaffected. Remaining sight can still be very useful, and with the help of low vision optical devices, people with this condition can continue many of their normal activities. The causes of myopic degeneration are not clearly understood, but they may include biomechanical abnormalities or hereditary factors. The biomechanical theory assumes that the retina, in a myopic eye, is stretched over a larger than normal area because the eye is longer in shape than is normal. Over time, the outer coat of the eye, known as the sclera, also stretches in response to forces like internal eye pressure. This stretching of the sclera is thought to lead to retinal degeneration. In the hereditary theory, the retinal changes are thought to be an unavoidable, inherited process. Loss of central vision can occur if abnormal vessels grow directly under the center of the retina in an area known as the macula. This is called choroidal neovascularization. Early diagnosis and treatment can minimize the amount of vision loss. People with myopic degeneration should have their vision monitored by an ophthalmologist on a regular basis. Using an Amsler grid to monitor vision at home is also helpful in detecting early growth of these abnormal vessels. Patients with myopic degeneration have an increased risk of developing peripheral retinal tears and retinal detachment. New flashes of light, “floaters,” “curtains” or “veils,” or loss of vision, should be evaluated by an ophthalmologist immediately.

Retinitis Pigmentosa (RP) Retinitis pigmentosa (RP) describes a group of related diseases that tend to run in families and cause a slow but progressive loss of vision. RP affects the rods and cones of the retina, the light-sensitive nerve layer at the back of the eye, and results in a decline in vision in both eyes. RP usually affects both eyes equally, with severity ranging from no visual problems in some families to blindness at an early age in others. RP gets its name from the fact that one of the symptoms is a clumping of the retinal pigment that can be seen during an eye exam. The earliest symptom of RP, usually noticed in childhood, is night blindness or difficulty with night vision. People with normal vision adjust to the dark quickly, but people with night blindness adjust very slowly or not at all. A loss of side vision, known as “tunnel vision,” is also common as RP progresses. Unfortunately, the combination of night blindness and the loss of peripheral vision can be severe and can lead to legal blindness in many people. While there is a pattern of inheritance for RP, 40% of RP patients have no known previous family history. Learning more about RP in your family can help you and your ophthalmologist predict how RP will affect you. Usher’s syndrome, a condition that causes both deafness and blindness, is a form of RP. The incidence of Usher’s syndrome is difficult to determine, but surveys of patients suggest up to 10% of RP patients are deaf. The incidence of Usher’s syndrome is three cases per 100,000 -- it is the most frequent cause of combined deafness and blindness in adults. Considerable research is being done to find the hereditary cause of RP. As hereditary defects are discovered, it may be possible to develop treatments to prevent progression of the disease. While developments are on the horizon, particularly in the area of genetic research, there is currently no cure for retinitis pigmentosa. Nutritional supplements may be of benefit in RP. It has been reported that vitamin A can slow the progression of RP. However, large doses of vitamin A are harmful to the body, and supplements of vitamin E alone may make RP worse. Vitamin E is not harmful if taken along with vitamin A or in the presence of a normal diet. Your ophthalmologist can advise you about the risks and benefits of vitamin A and how much you can safely take.

Despite visual impairment, people with RP can maintain active and rewarding lives through the wide variety of rehabilitative services that are available today. Until there is a cure, periodic examinations by your ophthalmologist will keep you informed of legitimate scientific discoveries as they develop.

Uveitis The uvea is the middle layer in the eye sandwiched between the retina (innermost layer) and the sclera (outermost layer). The uvea contains many blood vessels that carry blood to and from the eye. Uveitis is an inflammation of the uvea. Since the uvea nourishes many important parts of the eye, uveitis can damage your sight. Symptoms can include pain, “floaters,” blurriness, light sensitivity, and redness. Uveitis may develop suddenly with redness and pain or with just a blurring of vision. Causes of this condition include viruses like mumps, shingles, or herpes simplex; eye injuries; fungi or parasites; autoimmune diseases; and others. In most cases, the cause is unknown. Uveitis is diagnosed by an examination of the eye. In addition, your ophthalmologist may order blood tests, skin tests, or x-rays and also will collect information about your overall health in general.

Types of Uveitis There are different types of uveitis: iritis and choroiditis. With iritis, the uvea is inflamed near the front of the eye in the iris. Iritis has a sudden onset and may last up to eight weeks. Choroiditis is an inflammation in the back of the eye. It can develop more slowly than the other forms of uveitis and last longer, although this is variable. Because uveitis is a serious condition that can cause permanent damage to the eye, it needs to be treated as soon as possible. Eyedrops and pupil dilators reduce inflammation and pain. For more severe inflammation, oral medications or injections may be necessary. If uveitis is associated with other conditions like glaucoma or retinal damage, surgery may be required. If you have a “red eye” that does not clear up quickly, ocular pain, or other significant symptoms, see your ophthalmologist or optometrist as soon as possible.

Retinopathy of Prematurity (ROP) Retinopathy of prematurity (ROP) damages premature babies’ retinas, the layer of light-sensitive cells lining the back of the eye. ROP usually occurs in both eyes, though one may be more severely affected. The last 12 weeks of a full-term pregnancy are an especially active time for the growth of the eye. When a baby is born prematurely, blood vessels are not ready to supply blood to the retina. At birth, abnormal new blood vessels form and cause scarring or detachment of the retina. The condition is especially common in very small babies. It is more likely to occur in babies weighing one or two pounds than in babies weighing three pounds or more. Despite improved medical care, the disease is becoming more common because smaller and sicker infants are surviving. Supplemental oxygen given to premature babies may be part of the cause of ROP, but it is not the only factor as was once thought. In severe cases, the retina may be extremely scarred and detached. Many cases get better without treatment and only a small number of children go blind. Cryotherapy (freezing) or laser treatments can prevent progression of the disease. Children with ROP are more likely to develop nearsightedness and amblyopia (lazy eye). Eyeglasses, patching, and eye muscle surgery can help these associated problems. Follow-up examinations of severely affected children should continue periodically.

Macular Hole The macula is the part of the retina responsible for acute central vision, the vision you use for reading, watching television, and recognizing faces. A macular hole is a small, round opening in the macula. The hole causes a blind spot or blurred area directly in the center of your vision. Most macular holes occur in the elderly. When the vitreous (the gel-like substance inside the eye) ages and shrinks, it can pull on the thin tissue of the macula, causing a tear that can eventually form a small hole. Sometimes injury or long-term swelling can cause a macular hole. No specific medical problem is known to cause macular holes. Vitrectomy surgery, the only treatment for a macular hole, removes the vitreous gel and scar tissue pulling on the macula and keeping the hole open. The eye is then filled with a special gas bubble to push against the macula and close the hole. The gas bubble will gradually dissolve, but the patient must maintain a face-down position for one to two weeks to keep the gas bubble in contact with the macula. Success of the surgery often depends on how well the position is maintained.

With treatment, most macular holes shrink, and some or most of the lost central vision can slowly return. The amount of visual improvement typically depends on the length of time the hole was present.

Anti-VEGF for Other Retinal Diseases Certain anti-VEGF treatments are approved for a condition known as “wet” age-related macular degeneration (AMD), in which abnormal blood vessels grow underneath the retina. These unhealthy vessels leak blood and fluid that can swell and scar the macula (the central part of the retina), and vision loss may be rapid and severe. Since anti-VEGF therapies have shown good potential for slowing vascular leakage and preventing vision loss associated with wet AMD, ophthalmologists are using them to treat other causes of macular edema. If your ophthalmologist has diagnosed you with diabetic retinopathy, retinal venous occlusion, or other conditions, you may benefit from anti-VEGF treatment if other therapies are not producing the desired results or if your ophthalmologist thinks that anti-VEGF therapy is the best first course of action. Treatment with the anti-VEGF drug is usually performed by injecting the medicine with a very fine needle into the back portion of your eye. Your ophthalmologist will clean your eye to prevent infection and will administer an anesthetic into your eye to reduce pain. Usually, patients receive multiple anti-VEGF injections over the course of many months. There is a small risk of complications with anti-VEGF treatment, usually resulting from the injection itself. However, for most people, the benefits of this treatment outweigh the small risk of complications.

Receiving an Intravitreal Injection Prior to injection, your ophthalmologist will clean around your eye with a dilute iodine solution to reduce the small chance of infection. A metal speculum will be used to hold the eyelids open so you won't have to worry about blinking at the wrong time. A small amount of local anaesthetic will be injected into the outmost layer of tissue on the eye. Next the medication will be injected into the eye with a very fine needle. The speculum will then be removed and you will be done! The whole procedure takes less than five minutes. If you have glaucoma, your eye surgeon may check your intraocular pressure a couple of hours after the injection.

After your injection you will be instructed not to rub your eye or get water in your eye for three days. You may also be asked to use eyedrops four times a day for three days after the injection. If you have any problems like decreased vision, something dark coming in from the edges of your visual field, or pain in the eye, you should call the office as soon as possible. If your problem occurs after office hours or on the weekend, you should go to the Emergency Department nearest you. Most patients have a little discomfort from the iodine or the speculum, and most patients receiving kenalog injections can see the drug floating around in the eye; it is very rare to have a serious problem from the injection. Your ophthalmologist will schedule your next visit, usually for 4 weeks. Information about eye conditions, disorders and treatments is presented courtesy of the Eye Physicians & Surgeons of Ontario.