RETINA / AMD

All about Retinal Detachment: Retinal detachment is the separation of the retina from the choroid, a membrane dense with blood vessels that is located between the retina and the sclera ("white" of the eye). The retina is a thin layer of light sensitive tissue that lines the back portion of the eye. When the retina detaches, it is deprived of its blood supply and source of nourishment and loses its ability to function. This can impair vision to the point of blindness. Incidence and Prevalence Retinal detachment is relatively rare and occurs in about one in 15,000 (0.3%) of the U.S. population. It is most common in people middle-aged and older. About 6% of the population has retinal holes, but most of these do not lead to retinal detachment. Patients who are severely myopic (usually greater than 10 diopters) have a 5% risk for developing a detachment and patients who undergo cataract surgery have a 1% risk. The most common predisposing factor is myopia, accounting for 40% to 50% of detachments. About 33% have undergone cataract removal and 10–20% have experienced eye trauma. Types There are three types of retinal detachment: rhegmatogenous retinal detachment, tractional retinal detachment, and exudative retinal detachment. Rhegmatogenous retinal detachment is the most common type and occurs as a result of one or more small tears or holes in the retina. Fluid passes through the hole and flows between the retina and the choroid of the eye. This can cause the retina to separate from the choroid, resulting in detachment. Retinal tears can be caused by a number of factors; the most common is posterior vitreous detachment (PVD). The vitreous body is a large spherical chamber located between the lens and the retina. Vitreous is the clear, gel-like substance that fills the chamber. In a child’s eyes, the vitreous has a consistency similar to egg white and is firmly attached to the retina. As a person grows older, the vitreous may become thinner and more liquefied, shrinking away from the retina until it separates from it entirely. Vitreous separation occurs in about one-half of all persons by age 50. PVD is generally harmless and does not affect vision. However, as the vitreous shrinks it can pull on and tear the retina. Once a hole is formed, vitreous can seep through the tear, leading to retinal detachment. Patients who are nearsighted (myopic) are at risk for rhegmatogenous retinal detachment. The eyes of myopic patients are longer from front to back, and the retina is thinner and more fragile. Inflammation or injury may cause vitreous shrinkage, resulting in a tear. Eye surgery patients are also at risk, especially those who have undergone cataract removal. Cataract surgery is the most common surgical procedure performed on the eye and is the most prevalent surgical risk factor for retinal detachment. Approximately 20–40% of rhegmatogenous retinal detachments occur in patients who have had cataract removal. Tractional retinal detachment occurs when adhesions or scar tissue create enough traction on the retina to tear and detach it. The most common causes of tractional retinal detachment are: diabetic retinopathy, eye disorders caused by sickle cell disease, occlusions of retinal blood vessels, penetrating eye injury, retinopathy of prematurity. Fluid buildup underneath the retina causes exudative detachment. A disturbance in the blood–retina barrier results in the leakage of fluid into the "space" between the retina and the choroid. Conditions that can lead to this leakage include the following: Congenital anomalies, including Coat’s disease (disorder of retinal blood vessels) and nanophthalmos (extremely small eyes) Eye tumors, such as choroidal melanoma (malignancy of the choroid) Inflammatory conditions including posterior scleritis (inflammation of the sclera) and Vogt-Koyanagi-Harada syndrome (rare, severe inflammation of the iris, ciliary body, and choroid) Treatment for exudative detachment depends on the underlying cause. If the cause can be controlled, the prognosis is usually very good. What is the retina? Imagine that your eye is like a camera, and the retina is the film. The retina is a fine sheet of nerve tissue lining the inside of the eye (see diagram). Rays of light enter the eye and are focused on the retina by the lens. The retina produces a picture which is sent along the optic nerve for the brain to interpret. It's rather like the film in the camera being developed so that pictures can be produced. What is retinal detachment? Usually the retina is attached to the inner surface of the eye. If there is a tear or hole in the retina then fluid can get underneath it. This weakens the attachment so that the retina becomes detached - rather like wallpaper peeling off a damp wall. When this happens the retina cannot compose a clear picture from the incoming rays and your vision becomes blurred and dim. Who is more likely to get it? Detachment of the retina happens more to middle aged, short sighted people. It is quite uncommon however and only about one person in ten thousand is affected. Very rarely, younger people can have a weakness of the retina. What are the symptoms? The most common symptom is a shadow spreading across the vision of one eye. You may also experience bright flashes of light and/or showers of dark spots called floaters. These symptoms are never painful. Many people experience flashes or floaters and these are not necessarily a cause for alarm. However if they are severe and seem to be getting worse, and/or you are losing vision then you should see a doctor urgently. Prompt treatment can often minimise the damage to your eye. What is the treatment? If you get help early, it may only be necessary to have a laser or freezing treatment. This is usually performed under a local anaesthetic. Often however, an operation to repair the hole in the retina will be needed. This is usually done under a general anaesthetic and can be repaired with a single operation in 90 per cent of cases. This does not usually cause much pain but your eye will be sore and swollen for a few days afterwards. You will usually need to stay in hospital for two or three days after your operation. We want to reassure you that your surgeon does not take your eye out of its socket to operate on it. How much vision can I expect after a successful operation? This depends on how much the retina has detached and for how long. The shadow caused by the detachment will disappear in all cases when the retina has been put back in place. However, if the detachment involves the part of the retina which is responsible for your central vision, this may not recover. The longer this part of the retina has been detached, the smaller the chance that your central vision will recover to its former level. But, if this is the case, you will still have some useful vision left. What happens after the operation? Usually you can return home after two or three days in hospital. And you will be encouraged to get up and carry on as usual on the day after the operation. Sometimes you will be asked to keep your head in a particular position to help the healing process. You can resume normal activities, including sex, as soon as you feel able. What happens if the retina is not put back in place? Most people will lose all useful vision if no operation is carried out, or if the treatment is unsuccessful. Occasionally, if the detachment involves the lower portion of the retina, some vision may recover by itself. Can retinal detachment be prevented? If your family has a history of retinal detachment, or your doctor finds a weakness in your retina then preventive laser or freezing treatment may be needed. In most cases however it is not possible to take preventive action. Retinal detachment does not happen as a result of straining your eyes, bending or heavy lifting. Am I likely to get one in the other eye? If you have had a retinal detachment in one eye, you are at increased risk of developing one in the other eye. But there is only about a one in ten chance of this happening. What if my sight cannot be fully restored? Much can be done to help you use your remaining vision as fully as possible. You should ask your doctor to refer you to the hospital low vision clinic. There are a variety of optical aids such as brighter reading lights, simple magnifying glasses and more sophisticated equipment that can help you. RNIB can also advise you about the help that is available. Some FAQs on Detached Retina: If I see floaters and flashing lights do I need to see my eye doctor? Flashes and floaters are sometimes important signs that a retinal problem such as a retinal tear or detachment is present. Although flashes and floaters may not be serious, a retinal examination must be performed to be sure. What is the purpose of retinal detachment surgery? When the retina is detached, it cannot work and vision is lost. The purpose of the surgery for retinal detachment is to reattach the retina. If the surgery is successful, the vision will usually improve. If pneumatic retinopexy does not work, may I then undergo the scleral buckling procedure? If pneumatic retinopexy fails to reattach the retina, the patient usually can undergo a scleral buckling procedure. Does the silicone scleral buckle ever need to be taken off? Once a scleral buckle is sutured onto the wall (sclera) of the eye, it stays in position forever. It may slightly change the shape of the eye and, after the eye has healed, a new pair of glsses may be necessary. On rare occasions, a scleral buckle placed all the way around the eye may cause pain. If the pain is severe and cannot be relieved with medicine, it may be necessary to loosen or remove the buckle. Rarely, an infection may occur. In such instances, the buckle must be removed from the eye. When the buckle is removed, the retina usually remains attached, but may detach. In most cases, however, the scleral buckle remains against the eye forever and causes no serious problem. It cannot be seen by others. How is vitrectomy surgery performed? The surgery may be performed using either general anesthesia or local anesthesia depending on the particular case. Vitrectomy surgery is performed through an operating microscope, which allows the surgeon to look through the widely dilated pupil at the retina. Small openings through the sclera are made in order to insert vitrectomy instruments into the eye. A variety of instruments are used, including a fiberoptic light which lights the inside of the eye, and a variety of vitreous cutters, scissors, and forceps. How long will the vitreous or retinal surgery take? The length of the surgery depends on the type of problem you have. If you have an epiretinal membrane or uncomplicated retinal detachment, surgery may take less than an hour. However, if the eye needs to have the lens removed, a scleral buckle placed, and scar tissue removed from the eye, the surgery could take many hours. How long will I be in the hospital for my surgery? You will be admitted to the hospital the day before the day of surgery. Most patients are able to leave the hospital one or two days after surgery. Occasionally, patients may leave the hospital the same day, but sometimes a more lengthy stay may be necessary. Are there risks to general anesthesia? General anesthesia always carries a degree of risk. Minor risks include postoperative nausea, vomiting, and hiccupping. Some patients experience an upset stomach following surgery. If nausea does develop, it can be controlled with medication. Occasionally patients will experience some confusion and prolonged sleeping. Very rarely, serious reactions occur that result in liver failure, cardiac arrest, and even death. Will my eye hurt after surgery? You may note some discomfort around the eye, but severe pain is unusual. Discomfort can be relieved with medication if necessary. Your eye will remain swollen, red somewhat tender, and uncomfortable for several weeks. You may also notice a scratchy, foreign body sensation when opening or closing the eye. This is caused by small stitches on the outside of the eye. These stitches will gradually become soft and fall out, probably withing two weeks. What instructions must I follow when I go home after surgery? The amount of physical acitvity that is allowed depends on the type of surgery that you have had. Your surgeon will discuss with you any restrictions. You will be asked to use some eye medications when you go home. The purpose of the drops is to prevent infection and make the eye more comfortable as it heals. Will I see better right after surgery? The vision following surgery depends on the type of surgery that you have had. In general, it takes a long time for you to reach your best vision. The vision in the eye will almost certainly be blurry for many weeks. Your surgeon will discuss with you the chances of visual recovery following your surgery and how much vision you can hope to regain. It is important to realize that recovery of vision following any type of retinal or vitreous surgery takes a long time. Why is postoperative head positioning important and how long must it continue? Patients are asked to position themselves after surgery (usually face down) if they have air, gas, or silicone oil in their eye. These materials rise to the highest point in the eye. If there have been retinal tears that have received laser or cryotherapy during surgery, the air, gas, or oil can help keep the tear closed, and the retina attached, while the laser or cryotherapy takes hold. Occasionally, head positioning is used to allow blood in the eye to settle away from the macula. The length of time varies, and your surgeon will tell you when it is safe to stop this special positioning. Is it possible that I may not see after surgery? Despite our increasing knowledge about retinal detachment and vitreous disease, and despite the sophisticated technology that we can bring to the operating room, we may find ourselves unable to improve a patient's vision. The chance for blindness with severe retinal disease is real. When considering surgery, the patient and the doctor must weigh the risks, including the possiblity of total blindness, against the possible benefits of either stabilizing or improving vision. It is important for the patient to know that surgery may fail due to complications, or simply due to the progressive nature of the retinal disease. Is there a time when an eye is too hopelessly damaged to consider surgery? This is a difficult question. Whether to perform any surgery depends on whether the patient feels that the benefit of the surgery are worth the risks. This decision will be different for every patient, since every patient's needs are different. If an eye is badly damaged, there may not be much to gain with surgery, and a patient might decide not to have surgery. If, however, the patient has only one eye, then any vision that is saved will be tremendously important. No two patients, and no two retinal problems, are alike. Your surgeon will help you understand what you can hope to gain with surgery, and what risk to lose.

Ageing (Senile) Macular Degeneration: Macular degeneration is the progressive deterioration of the macula, the small central area of the retina. The central macula, the fovea, is responsible for fine-detail vision and has the highest concentration of color receptors (i.e., cone cells). The most common type of macular degeneration is called age-related macular degeneration (AMD), because it usually develops in patients over the age of 55. A rare form of macular generation, called juvenile macular degeneration (JMD), occurs in younger patients, including infants and children. JMD is an inherited disorder caused by mutated genes. Incidence and Prevalence Macular degeneration is diagnosed every 3 minutes in the United States. It occurs in about 10% of people over the age of 50, and about 33% of people over 75. AMD is most common in Caucasians of European decent and is more prevalent in women. Every year 1.2 million people with macular degeneration lose part of their central vision, and 200,000 suffer complete loss of central vision in one or both eyes. Types Age-Related Macular Degeneration Because AMD primarily affects central vision, patients usually do not lose vision completely, even at very advanced stages. This disorder can make it difficult to read, drive, work at a computer, and perform other activities that require clear central vision. AMD occurs in two forms, dry and wet. Dry (atrophic) This form of AMD accounts for 85–90% of all cases. The earliest sign of AMD is the development of waste material deposits, called drusen, that appear as tiny orange or yellow dots among the retinal epithelial (RPE) cells. These deposits are initially tiny and few in number, but they may grow larger and become more numerous. The presence of drusen does not necessarily signal vision loss, and many people with drusen continue to have good vision for decades. As dry AMD progresses, mild to moderate visual acuity loss may occur. Over time, patches of RPE cells may die, leaving "bare" spots. This is called geographic atrophy and results in vision loss in the affected areas of the retina. If these patches become large and involve the fovea, visual acuity can deteriorate to the point of legal blindness. Geographic atrophy is a severe form of dry macular degeneration. Wet (vascular) The wet form accounts for approximately 10% of cases but is responsible for the vast majority of severe, AMD-related vision loss. Vascular macular degeneration begins as the dry form and progresses to the wet form when abnormal blood vessels develop. In wet AMD, abnormal blood vessel growth is triggered by mechanisms that are not completely understood. The new vessels are very delicate, break easily, and bleed and leak fluid into surrounding tissue. This can damage the macula very quickly and may cause central vision loss in a short time. The risk for progression from dry to wet AMD is approximately 14-87% over 5 years and depends on many factors. What is macular degeneration? Macular degeneration is the physical disturbance of the center of the retina called the macula. The macula, which is about the size of the capital letter "O" in this sentence, is the part of the retina which is capable of our most acute and detailed vision. We use the macula for reading, driving, recognizing faces, watching television, and fine work. Macular degeneration is the leading cause of legal blindness in people over age 55. (Legal blindness means that a person can see 20/200 or less with eyeglasses.) Even with a loss of central vision, however, color vision and peripheral vision may remain clear. Vision loss usually occurs gradually and typically affects both eyes at different rates. What causes macular degeneration? The root causes of macular degeneration are still unknown. There are two forms of age-related macular degeneration, "wet" and "dry". Seventy percent of patients have the "dry" form, which involves thinning of the macular tissues and disturbances in its pigmentation. Thirty percent have the "wet" form, which can involve bleeding within and beneath the retina, opaque deposits, and eventually scar tissue. The "wet" form accounts for ninety percent of all cases of legal blindness in macular degeneration patients. Different forms of macular degeneration may occur in younger patients. These non-age related cases may be linked to heredity, diabetes, nutritional deficits, head injury, infection, or other factors. The Schepens scientists are undertaking the basic research necessary to determine the causes of these disorders. Finding the cause is the first important step toward prevention and cure. How is macular degeneration detected? Declining vision noticed by the patient or by an ophthalmologist during a routine eye exam may be the first indicator of macular degeneration. The formation of new blood vessels and exudates, or "drusen," from blood vessels in and under the macular is often the first physical sign that macular degeneration may develop. In addition, the following signs may be indicative of macular problems. Anyone experiencing these symptoms should consult an ophthalmologist immediately: Straight lines appear distorted and, in some cases, the center of vision appears more distorted than the rest of the scene. A dark, blurry area or "white-out" appears in the center of vision. Color perception changes or diminishes. The following are NOT known to be linked to macular degeneration: floaters (moving spots caused by debris floating in the vitreous fluid between the lens and the retina); dry eye syndromes; cataracts and cataract surgery. Is early detection important? Early detection is important because a patient destined to develop macular degeneration can sometimes be treated before symptoms appear, and this may delay or reduce the severity of the disease. Furthermore, as we develop better treatments for macular degeneration, whether they are medicinal, surgical, or low vision aids, those patients diagnosed with macular degeneration can sooner benefit from them. If I have macular degeneration in one eye, will it develop in the other? Yes, this is usually the case. In the early stages, only one eye may be affected, but as the disease progresses, both eyes are usually affected. Is there a cure for Macular Degeneration? At this time there is no known cure for macular degeneration. In some cases, macular degeneration may be active and then slow down considerably, or even stop progressing for many, many years. One day, research may show us how to prevent and reverse the disease. Today, there are ways to arrest macular degeneration, depending on the type and the degree of the condition. These range from nutritional intervention to laser surgery of the blood vessels (see below). We also have developed low vision aids and techniques for maximizing the use of peripheral vision to help patients adapt better to their loss of central vision. Educating susceptible groups about macular degeneration can enhance early detection and early treatment. We advise that a patient select and eye center that specializes in macular degeneration and get opinions for treatment from retina specialists. Can nutrition help treat macular degeneration? Some scientists have suggested an association between macular degeneration and high saturated fat, low carotenoid pigments, and other substances in the diet. There is evidence that eating fresh fruits and dark green, leafy vegetables (such as spinach and collard greens) may delay or reduce the severity of age-related macular degeneration. Taking anti-oxidants like Vitamins C and E may also have positive effects. Zinc, however, has shown mixed results. In some people, the long-term use of zinc causes digestive problems and anemia; its use is probably not worth the potential problems. Selenium is sometimes recommended, but you should always consult your physician to determine appropriate dosages. The Schepens is committed to continued research in nutrition and its effect on macular degeneration. Can surgery help cure macular degeneration? Surgery to remove the scar produced by macular degeneration has been successful in younger patients, but less successful in older patients. If the degeneration is associated with leaking blood vessels in the center of the macula, and vision is worse than 20/70, laser surgery, called photocoagulation, is recommended. This will not improve vision but generally reduces further vision loss. Retinal transplantation is a new experimental approach to macular degeneration, but will require at least 3 - 5 years of clinical research at The Schepens and other centers to determine its safety and effectiveness. Is macular degeneration hereditary? Macular degeneration appears to be hereditary in some families but not in others. Since macular degeneration affects most patients later in life, it is difficult to study successive generations in a family. Recent studies of twins indicate that both genetic and non-genetic factors play important roles in age-related macular degeneration. Research to determine the genes associated with hereditary macular degeneration will help lead to early detection, early intervention, and possible cures. What can I do to help prevent and cure macular degeneration? Have annual routine eye exams See your ophthalmologist without delay if you notice any decline in your vision Does sunlight affect macular degeneration? Yes. It has been demonstrated that the blue rays of the spectrum seem to accelerate macular degeneration more than other rays of the spectrum. This means that very bright light, such as sunlight or its reflection in the ocean and desert, may worsen macular degeneration. Special sunglasses that block out the blue end of the spectrum may decrease the progress of the disease. Again, more research is needed in this area. Does hypertension (or medication for hypertension) affect macular degeneration? Yes. Hypertension tends to make some forms of macular degeneration worse, especially in the "wet" form where the retinal tissues are invaded by new blood vessels. The medications used to treat hypertension have not been shown to have any direct effect on macular degeneration, but they may slow progression of the disease by reducing hypertension. Does smoking or second hand smoke contribute to macular degeneration? Yes. Any type of smoking or exposure to tobacco smoke can accelerate the development of the "wet" type of macular degeneration.