Age related Macular Degeneration
1. What is macular degeneration?
In macular degeneration, the light-sensing cells of the macula malfunction and may over time cease to work. Macular degeneration occurs most often in people over 60 years old, in which case it is called Age Related Macular Degeneration (ARMD). Much less common are several hereditary forms of macular degeneration, which usually affect children or teen-agers. Collectively, they are called Juvenile Macular Degeneration. They include Best’s Disease, Stargardt’s Disease, Sorsby’s Disease and some others.
2. Who gets ARMD?
Macular Degeneration is the leading cause of new blindness in adults over the age of 60 in this country. The disease also causes less severe but significant reductions in the ability to see and perform everyday tasks. A study done by National Eye Institute showed that Macular Degeneration occurs in approximately one out of five people between the ages of 65 to 74. One of three people over age 75 in this country will suffer some visual impairment due to Macular Degeneration.
3. What are the types of ARMD?
The “dry” form of ARMD refers to the atrophic form which is characterized, in its late stages, by the degeneration (i.e. atrophy) of the retina in a region that includes the macula. “Dry” ARMD develops and progresses slowly over a period of 5-10 years or longer. Appoximately 85% of the total ARMD patient population has this atrophic form. The less prevalent, “wet” type of ARMD is also referred to as neovascular or exudative ARMD. It is characterized by the ingrowth of new blood vessels from the choroid. “Wet” ARMD progresses much more rapidly, over a period of weeks or months, and usually results in legal blindness in the central portion of the visual field.
4. How do you evaluate ARMD?
Clinical examination, coupled with fluorescein angiography, Optical coherence tomography and in some cases, indocyanine green angiography are the tests useful in finding out the type of ARMD0, its prognosis and outcome.
4. How do you evaluate ARMD?
Clinical examination, coupled with fluorescein angiography, Optical coherence tomography and in some cases, indocyanine green angiography are the tests useful in finding out the type of ARMD0, its prognosis and outcome.
6. If you have drusen, does that mean you will eventually develop ARMD?
Not necessarily. Many individuals with some drusen do not go on to develop the visual symptoms of ARMD. From a clinical standpoint, drusen must attain a threshold in numbers, size, and shape for them to become a matter of concern to ophthalmologists.
7. What are the risk factors associated with ARMD?
The strongest risk factors are:
- Age. The incidence of all forms of ARMD rises steeply with advancing age. In one large study, ARMD increased from approximately 4% of individuals at 43 to 54 years of age, to 23% in those 75 years or older.
- Drusen. The presence of numerous and/or large drusen, accompanied by specific pigmentary changes in the macula, is considered to be diagnostic of early atrophic ARMD.
- Smoking. The incidence of both “wet” and “dry” ARMD is strongly correlated a history of smoking, and the degree of risk is proportional to the amount of cigarette consumption.
- Genetic factors. Several studies have demonstrated a high rate of concordance in the development of ARMD among twins, particularly among identical twins. In family-based studies, the likelihood of developing ARMD is nearly 20 times higher if one or both parents have ARMD. It is highly likely that one or more gene alterations carried by the affected individual increase the susceptibility in his/her offspring.
- Current evidence for the following additional risk factors is either weak, conflicting, or unpersuasive: gender, social class, ethnicity, cardiovascular disease, high blood pressure, dietary fat intake, cholesterol levels, alcohol consumption, estrogen levels, light exposure, and circulating levels of vitamins, minerals, and anti-oxidants.
8. How does diet influence macular degeneration?
Several studies now indicate that diets rich in green leafy vegetables, such as spinach, chard and mustard greens, can reduce the risk of ARMD. These and other vegetables are rich in certain pigments known as carotenoids. Among these, lutein and zeaxanthin are two that are highly concentrated in the macula where they may have effects that protect RPE and/or retinal cells from injury caused by the formation of peroxides and other toxic byproducts of the visual cycle . Lutein and zeaxanthin are now widely available as dietary supplements; however, their efficacy when consumed in this form has not been well studied.
9. Have vitamins and other nutritional supplements been shown to be effective as treatments for ARMD?
There have been at least five published trials that have tried to determine whether dietary supplements, such as vitamins A, C, E or zinc can arrest or prevent the development of ARMD. Thus far, the results from these small scale studies have not been encouraging. However, new data from a much larger study called the Age-Related Eye Disease Study (AREDS) indicates that dietary supplementation with 500 mg of vitamin C, 400 IU of vitamin E, 15 milligrams of beta-carotene and 80 milligrams of zinc (as zinc oxide) can reduce the risk of developing advanced ARMD by approximately 25%.
10. What are the Treatments for Macular Degeneration?
Earlier, there were no treatments for macular degeneration. About 15 to 20 years back, laser photocoagulation was used for the first time to treat ARMD. For the last 5 years, newer treatments, which are more effective, are coming up. The most commonly applied clinical approach to Age Related Macular Degeneration is one in which in some cases can slow the progression of the disease, but does not restore already lost vision. This is possible with special laser called Photodyanamic therapy. Newer therapeutic approaches include Photodynamic therapy along with intravitreal injections like Lucentis, Macugen or Avastin.
Flashes and Floaters
1. What causes light flashes?
Light flashes are sometimes caused by mechanical stimulation of the retina, often referred to as “pulling”, “forces”, or “traction”.
2. What can cause this pulling on the retina?
A variety of conditions can cause it, including:
posterior vitreous separation, retinal tears (breaks), and scarring on the surface of the retina. Some macular disease patients experience flashes in the central field of vision (straight ahead vision). Patients with successfully repaired retinal tears and detachments may have flashes for many months.
3. So what are the common causes?
Actually the most common cause of light flashes is the vitreous humor pulling away from the retina. This happens in over 70% of the population as part of the normal aging process, or for other reasons that are not well understood at this time. It is usually accompanied by “floaters”, which represent condensations of the vitreous jelly. By comparison, retinal breaks occur in approximately 6% of the population, and retinal detachments in about 0.06%. Light flashes occur in all three conditions.
4. How is cholesterol measured?
Checking the blood will tell you the cholesterol levels. The “good cholesterol” should be kept high while the “bad cholesterol” should be kept low. You can use the chart below to see if your total cholesterol is high. Consult your doctor regarding the normal values.
5. Can light flashes be caused any other diseases?
Yes. Migraine can cause a jagged and flickering area of blocked vision with bright borders. It typically starts near the center of the vision and progresses to the peripheral vision before disappearing after about 30 minutes. This phenomenon is followed by a headache in only 50% of cases. Although patients describe this as occurring in one eye, in fact it occurs in the corresponding sides of the visual field in both eyes, as can be determined by covering one eye followed by the other when these are occurring.
Migraines are thought to be caused by blood flow disturbances to the visual part of the brain. Blood flow problems can also occur with cervical spine problems, inflammation of the optic nerve, and hardening of the arteries, as well as very low blood pressure. Low blood pressure can cause people to see stars or specks of light, particularly if they change position quickly. An example would be standing quickly from a sitting position or rising quickly after stooping or bending over. Pregnancy related high blood pressure (pre-eclampsia) can also cause light flashes.
6. Can light flashes cause total blindness?
No, but flashes can be related to retinal tears (breaks) or detachment, which can result in blindness if not treated.
7. What is a floater?
Floaters are relatively transparent, vague, usually curved objects that are seen best when looking at a white piece of paper, blue sky, light colored ceiling, or wall. They sometimes look like cobwebs, worms, rings, dots, or specks. Eye movement makes floaters more visible as they swirl about like seaweed in the ocean surf.
8. What is the most common cause of floaters?
They are usually caused by a clumping of pre-existing vitreous fibers in the eye. Therefore, doctors usually refer to them as vitreous condensations.
9. Are there any other causes?
Some floaters are red blood cells or blood clots on the surface of the retina or floating in the vitreous. Blood cells in the vitreous may occur with some retinal tears but do not necessarily indicate a tear. Occasionally, the vitreous can pull on a blood vessel on the surface of the retina and cause bleeding without causing a tear of the retina. Vascular disorders such as diabetic retinopathy and sometimes vein occlusion can cause bleeding in the back of the eye.
Rarely, floaters may be inflammatory in origin. Diseases such as pars planitis and uveitis can cause the formation of clumps of white blood cells (cells that the body produces when there is inflammation).
In 5-30% of cataract surgery procedures a thin layer of tissue forms behind the intraocular lens implant causing a decrease in vision. A YAG laser is then used to make an opening the lens capsule which usually results in better vision, but can also cause floaters.
10. Can floaters cause total blindness?
No, only a slight blockage of the vision at worst. Floaters are usually not detectable by visual testing unless they are very severe.
Importantly, floaters can be related to retinal detachment or a variety of vascular conditions such as diabetic retinopathy, which can result in blindness if not treated.
11. How common are flashes and floaters?
Very common. Over 70% of the population experiences these problems.
If one eye develops flashes or floaters will the other develop them as well?
Very likely: in the case of a posterior vitreous separation, it is very common for the same condition to occur in the second eye within a year.
For this reason, and because flashes and floaters are sometimes caused by retinal breaks, both eyes should have a dilated retinal examination as soon as possible when flashes or floaters develop in either eye.
12. What is the treatment for flashes and floaters?
If light flashes are due to a posterior vitreous separation and no retinal breaks (tears) are found on careful examination with the pupil dilated, no treatment is necessary. If tears are found by the doctor, laser or occasionally freezing (cryo) treatment is needed. A vitrectomy can be used to remove floaters but is used only in select conditions, when the patient is very much incapacitated by floaters.
1. What is retinal detachment?
Retinal detachments often develop in eyes with retinas weakened by a hole or tear. This allows fluid to seep underneath, weakening the attachment so that the retina becomes detached – rather like wallpaper peeling off a damp wall.
2. Who is at risk?
Detachment occurs in people who are
- Are extremely near-sighted
- Have had a retinal detachment in the other eye
- Have a family history of retinal detachment
- Have had cataract surgery
- Have other eye diseases or disorders, such as retinoschisis, uveitis, degenerative myopia, or lattice degeneration
- Have had an eye injury
3. 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. If your ophthalmologist has seen your retina and has reassured you, it is alright. However, if they are severe and seem to be getting worse and you are losing vision, then you should seek your ophthalmologists help. Prompt treatment can often minimise the damage to your eye.
4. What is the treatment?
If you get help early, it may only be necessary to have laser or freezing treatment. This is usually performed under a local anaesthetic.
Frequently, however, an operation will be needed to repair a hole or put the retina back in place. This is usually done under a local anaesthesia. In 90 per cent of cases the retina can be repaired with a single operation. The operation does not usually cause much pain, but your eye will be sore and swollen for a few days afterwards. Typically, you will be in hospital for a few hours or an overnight stay, depending on your particular condition. We want to reassure you that the surgeon does not take your eye out of its socket to operate on it.
5. When should I start having my cholesterol level checked?
Men aged 35 and older and women aged 45 and older should have their cholesterol checked periodically. Depending on what your cholesterol level is and what other risk factors for heart disease you have, you may need to have it checked more often. High cholesterol may run in families. Know your family history and discuss it with your doctor
6. 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 usually disappear when the retina has been put back in place. If your ability to see fine detail has been damaged before the operation, this may not fully recover afterwards. However after surgery your vision can improve slowly upto one year to come near normal. If we can operate the retinal detachment in less than a week, 80 % or more will have good vision after surgery.
7. What happens after the operation?
You will be encouraged to get up and carry on as usual on the day after the operation, although sometimes you will be asked to keep your head in a particular position to help the healing process. Your eye specialist will prescribe eye drops and you will need to use these for a few weeks.
You can resume normal activities, including sex, as soon as you feel able.
8. What happens if the detached 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.
However, further treatment is usually possible if it does not succeed the first time. Occasionally, if the detachment involves the lower portion of the retina, some vision may recover by itself.
9. 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. However, in most cases it is not possible to take preventive action.
Retinal detachment does not happen as a result of straining your eyes, bending or heavy lifting.
10. What about my other eye?
If you have had a retinal detachment in one eye, you are at an increased risk of developing one in the other eye. But there is only about a one in ten chance of this happening.
1. What is diabetic retinopathy?
Diabetic retinopathy is a complication of diabetes and a leading cause of blindness. It occurs when diabetes damages the tiny blood vessels inside the retina, the light-sensitive tissue at the back of the eye. A healthy retina is necessary for good vision. If you have diabetic retinopathy, at first you may notice no changes to your vision. But over time, diabetic retinopathy can get worse and cause vision loss. Diabetic retinopathy usually affects both eyes.
2. What are the stages of diabetic retinopathy?
Diabetic retinopathy has four stages:
Mild Nonproliferative Retinopathy. At this earliest stage, microaneurysms occur. They are small areas of balloon-like swelling in the retina’s tiny blood vessels.
Moderate Nonproliferative Retinopathy. As the disease progresses, some blood vessels that nourish the retina are blocked.
Severe Nonproliferative Retinopathy. Many more blood vessels are blocked, depriving several areas of the retina with their blood supply. These areas of the retina send signals to the body to grow new blood vessels for nourishment.
Proliferative Retinopathy. At this advanced stage, the signals sent by the retina for nourishment trigger the growth of new blood vessels. This condition is called proliferative retinopathy. These new blood vessels are abnormal and fragile. They grow along the retina and along the surface of the clear, vitreous gel that fills the inside of the eye. By themselves, these blood vessels do not cause symptoms or vision loss. However, they have thin, fragile walls. If they leak blood, severe vision loss and even blindness can result.
3. Who is at risk for diabetic retinopathy?
All people with diabetes–both type 1 and type 2–are at risk. That’s why everyone with diabetes should get a comprehensive dilated eye exam at least once in 6 months. Between 40 to 45 percent of people diagnosed with diabetes have some stage of diabetic retinopathy. If you have diabetic retinopathy, your doctor can recommend treatment to help prevent its progression.
During pregnancy, diabetic retinopathy may be a problem for women with diabetes. To protect vision, every pregnant woman with diabetes should have a comprehensive dilated eye exam as soon as possible. Your doctor may recommend additional exams during your pregnancy.
4. How does diabetic retinopathy cause vision loss?
Blood vessels damaged from diabetic retinopathy can cause vision loss in two ways:
Fragile, abnormal blood vessels can develop and leak blood into the center of the eye, blurring vision. This is proliferative retinopathy and is the fourth and most advanced stage of the disease. Fluid can leak into the center of the macula, the part of the eye where sharp, straight-ahead vision occurs. The fluid makes the macula swell, blurring vision. This condition is called macular edema. It can occur at any stage of diabetic retinopathy, although it is more likely to occur as the disease progresses. About half of the people with proliferative retinopathy also have macular edema.
5. Does diabetic retinopathy have any symptoms?
Diabetic retinopathy often has no early warning signs. Don’t wait for symptoms. Be sure to have a comprehensive dilated eye exam at least once a year.
6. What are the symptoms of proliferative retinopathy if bleeding occurs?
At first, you will see a few specks of blood, or spots, “floating” in your vision. If spots occur, see your eye care professional as soon as possible. You may need treatment before more serious bleeding occurs. Hemorrhages tend to happen more than once, often during sleep.
Sometimes, without treatment, the spots clear, and you will see better. However, bleeding can reoccur and cause severely blurred vision. You need to be examined by your eye care professional at the first sign of blurred vision, before more bleeding occurs.
If left untreated, proliferative retinopathy can cause severe vision loss and even blindness. Also, the earlier you receive treatment, the more likely treatment will be effective.
7. How are macular edema and diabetic retinopathy detected?
Macular edema and diabetic retinopathy are detected during a comprehensive eye exam that includes:
Visual acuity test. This eye chart test measures how well you see at various distances.
Dilated eye exam. Drops are placed in your eyes to widen, or dilate, the pupils. Your eye care professional uses a special magnifying lens to examine your retina and optic nerve for signs of damage and other eye problems. After the exam, your close-up vision may remain blurred for several hours.
Tonometry. An instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.
Your eye care professional checks your retina for early signs of the disease, including:
Leaking blood vessels.
Retinal swelling (macular edema).
Pale, fatty deposits on the retina–signs of leaking blood vessels.
Damaged nerve tissue.
Any changes to the blood vessels.
If your eye doctor believes you need treatment for macular edema, he or she may suggest a fluorescein angiogram. In this test, a special dye is injected into your arm. Pictures are taken as the dye passes through the blood vessels in your retina. The test allows your eye care professional to identify any leaking blood vessels and recommend treatment. Then they will do another test called optical coherence tomography (OCT) which allows one to check the thickness at the macula and to see any edema or traction. Based on these two tests the treatment is planned.
8. How is a macular edema treated?
Macular edema is treated with laser surgery. This procedure is called focal laser treatment. Your doctor 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. Further treatment may be needed.
A patient may need focal laser surgery more than once to control the leaking fluid. If you have macular edema in both eyes and require laser surgery, generally only one eye will be treated at a time, usually several weeks apart.
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. Contact your eye doctor if you have vision loss.
Another way of treatment is the intravitreal injections. They are injected into the eye in sterile conditions in an operation theatre. After that, the macular edema comes down. The common injections we use are Avastin and Macugen.
If these methods do not work, then we do try surgery in some patients as indicated by the fluorescein angiography and OCT.
9. How is diabetic retinopathy treated?
During the first two 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.
Severe to very severe diabetic retinopathy and proliferative retinopathy is treated with laser surgery. This procedure is called scatter laser treatment. Scatter laser treatment helps to shrink the abnormal blood vessels. Your doctor places 1,000 to 3,000 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, three or more sessions usually are required to complete treatment. Although you may notice some loss of your side vision, scatter laser treatment can save the rest of your sight. Scatter laser treatment may slightly reduce your color vision and night vision.
Scatter laser treatment 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, scatter laser treatment may still be possible, depending on the amount of bleeding. Intravitreal avastin or macugen injections are also used in many cases to stop bleeding.If the bleeding is severe, you may need a surgical procedure called a vitrectomy. During a vitrectomy, blood is removed from the center of your eye.
10. What happens during laser treatment?
Both focal and scatter laser treatment are performed in your hospital. Before the surgery, your doctor 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 office will be dim. As you sit facing the laser machine, your doctor 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. If your eye hurts, your doctor can suggest treatment.
11. What is a vitrectomy?
If you have a lot of blood in the center of the eye (vitreous gel), you may need a vitrectomy to restore your sight. If you need vitrectomies in both eyes, they are usually done several weeks apart.A vitrectomy is performed under either local or general anesthesia. Your doctor makes a tiny incision in your eye. Next, a small instrument is used to remove the vitreous gel that is clouded with blood. The vitreous gel is replaced with a salt solution. Because the vitreous gel is mostly water, you will notice no change between the salt solution and the original vitreous gel.
You will probably be able to return home after the vitrectomy. Some people stay in the hospital overnight. Your eye will be red and sensitive. You will need to wear an eye patch for a few days or weeks to protect your eye. You also will need to use medicated eyedrops to protect against infection.
12. Are scatter laser treatment and vitrectomy effective in treating proliferative retinopathy?
Yes. Both treatments are very effective in reducing vision loss. People with proliferative retinopathy have less than a five percent chance of becoming blind within five years when they get timely and appropriate treatment. Although both treatments have high success rates, they do not cure diabetic retinopathy. Once you have proliferative retinopathy, you always will be at risk for new bleeding. You may need treatment more than once to protect your sight
13. What can I do if I already have lost some vision from diabetic retinopathy?
If you have lost some sight from diabetic retinopathy, ask your eye doctor about low vision services and devices that may help you make the most of your remaining vision. Many community organizations and agencies offer information about low vision counseling, training, and other special services for people with visual impairments.
14. What can I do to protect my vision?
We urge everyone with diabetes to have a comprehensive dilated eye exam at least once in 6 months. If you have diabetic retinopathy, you may need an eye exam more often. People with proliferative retinopathy can reduce their risk of blindness by 95 percent with timely treatment and appropriate followup care.
A major study has shown that better control of blood sugar levels slows the onset and progression of retinopathy. The people with diabetes who kept their blood sugar levels as close to normal as possible also had much less kidney and nerve disease. Better control also reduces the need for sight-saving laser surgery.
RETINAL ARTERIAL BLOCKS
Retinal detachments often develop in eyes with retinas weakened by a hole or tear. This allows fluid to seep underneath, weakening the attachment so that the retina becomes detached – rather A retinal artery occlusion occurs when the central retinal artery or one of the arteries that branch off of 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. Retinal artery obstruction is like a stroke in the eye. the damage can be relatively mild or quite severe, depending on the extent to which the blood flow has been disrupted.
Treatments to improve vision in retinal artery occlusion can work only if the patient can reach the OT within an hour of the incident.. Some patients experience a substantial improvement in vision that usually occurs in the first few hours or days after onset of the symptoms.
It is extremely important that the eye care is closely followed after a retinal artery obstruction. An uncommon but significant complication is the development of a severe form of glaucoma, which can completely eliminate vision and cause the eye to be red and painful. Laser treatment can be used to reduce the glaucoma, though it does not improve vision. Newer treatments like intravitreal injections are helpful in the management of neovascular glaucoma.
Any patient with CRAO or BRAO should have a medical evaluation to look for source of embolism. Often the blockage is the result of hardening or cholesterol deposition in the arteries, with a fragment of cholesterol or a clot breaking off from a large blood vessel and floating to eventually obstruct a smaller blood vessel in the eye. An evaluation by a cardiologist is usually quite helpful in identifying the source of the obstruction. It may be necessary to undergo blood tests or other diagnostic tests such as ultrasound of the heart and neck. Sometimes anticlotting agents are helpful in preventing future blockages. Though these medications will not improve the sight in your affected eye, they may have a long-term benefit for you.
If a patient experiences any marked decrease in vision, or if the eye becomes painful, see your doctor immediately. Otherwise, keep to scheduled appointments.
RETINAL VENOUS BLOCKS
Central retinal venous blocks occur when there is a congestion to blood flow and an increase in backpressure on the central retinal vein. It causes variable degree of visual loss and can be easily diagnosed by a retinal examination. It is commonly seen in hypertensives and diabetics. Some times it can be seen in people with clotting abnormalities also.
Common symptoms are sudden onset blurring of vision and some times may present with severe glaucoma.
Evaluations are done to see if there is retinal ischemia or edema at the macula (central retina) A fluorescein angiography and OCT are usually done to look for these. Management is by laser photocoagulation of ischemic areas or by intravitreal injections.
Some cases of central retinal vein occlusions are treated by surgical methods including radial optic neurotomy.
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