• Macular
    Degeneration
  • Macular Pucker/
    Epiretinal Membrane
  • Macular
    Hole
  • Diabetic
    Retinaopathy
  • Flashes &
    Floaters
  • Retinal Tears/
    Detachment

MACULAR DEGENERATION

Macular degeneration is a term that includes a variety of eye diseases that affect your central vision. Age-related macular degeneration (AMD) is the most common form of macular degeneration. AMD is a premature aging of the cells in the area of retina responsible for detailed central vision. This area of the eye is called the macula.

Age-related macular degeneration is the leading cause of legal blindness in people older than 55 years in the United States. The disease affects more than 10 million Americans, including 23% of Americans older than 90 years. Because overall life expectancy continues to increase, age-related macular degeneration has become a major public health problem.

There are 2 types of age-related macular degeneration.

“Dry” Macular Degeneration : Multiple, small, yellowish deposits develop underneath the central retina called drusen. Drusen are the main feature of dry macular degeneration. As drusen accumulate underneath the central retina in an area called the macula, the macula can become thin and the retinal cells begin to function poorly.

Many people with drusen have excellent vision and no symptoms at all. However, some develop mild to moderate vision loss if the drusen worsen and the retinal cells are significantly affected. When visual loss develops, this generally happens slowly over a period of years.

Most people with age related macular degeneration begin with the “dry” form of the disease. The dry form accounts for 90% of all cases of age-related macular degeneration. Dry AMD progresses slowly, and most patients maintain useful vision throughout life.

“Wet” macular degeneration: Choroidal neovascularization – CNV : Newly-formed abnormal blood vessels, called choroidal neovascularization, are the hallmark of wet macular degeneration. These abnormal blood vessels grow between the retina and the deeper layers of the eye wall,
in the area of the macula.

These blood vessels will spontaneously leak fluid, bleed, and scar the retina. This process causes distortion and damage of the central retina. Vision distortion, visual blur, and/or a blind spot can develop suddenly with the development of choroidal neovascularization.

Most patients who develop wet macular degeneration have some degree of pre-existing dry macular degeneration. Although wet macular degeneration affects only 10% of people who have age-related macular degeneration, it accounts for the majority of people who have significant visual loss. More than 200,000 new cases of wet age-related macular degeneration occur each year in the US.

Diagnosis

Initial tests include measurement of the sharpness of your vision and a retina exam. If your doctor finds signs of macular degeneration, pictures of the retina can be taken to assess the extent of the disease and to detect "wet" macular degeneration. Tests may include these:

Fluorescein angiography: A special dye is injected into your arm. Then photographs of your retina are taken as the dye passes through the retina. The test is used to determine if "wet" macular degeneration exists. It also locates and measures the extent of the disease to determine the best treatment option.

Indocyanine green angiography: This test uses infrared wavelengths to view your retina. ICG angiography may help further characterize "wet" macular degeneration, and can be helpful in cases where the exact origin of the abnormal blood vessel cannot be determined by fluorescein angiography alone (i.e. occult neovascular membranes).

Treatment

Treatments: As there is no cure for aging, there is no cure for macular degeneration. However, proven treatments are available which can slow or halt the progression of the disease and sometimes improve vision in many patients.

1. Vitamins: The Age Related Eye Disease Study (AREDS) showed that antioxidants and vitamins reduce the risk of vision loss in patients with moderate to advanced “dry”age-related macular degeneration. The nutrients evaluated by the AREDS are contained in several different formulations, which are now available over the counter. However, these formulations are not without risk (i.e. increased chance of lung cancer in smokers). A consultation with your eye doctor is recommended to determine if vitamins may benefit you. More information regarding the AREDS vitamin formulation is available on the website of the National Eye Institute: www.nei.nih.gov/amd/

2. Intravitreal Injections: Several medicines have been proven effective for treatment of “wet” macular degeneration by injection directly into the eye. Drug therapy is currently the preferred first-line treatment for “wet” age related macular degeneration.

3. Photodynamic therapy: A light-activated drug called verteporfin (Visudyne®) is given intravenously. Shortly after the administration of the drug, a “cold” laser is used to close the abnormal vessels. Photodynamic therapy is used for treatment of “wet” macular degeneration.

4. Laser treatment: Laser surgery was the first proven treatment for “wet” macular degeneration. Patients with neovascularization outside the center of vision may be treated with a “hot” laser to directly destroy the abnormal blood vessels. Only a small percentage of patients with “wet” macular degeneration are good candidates for this treatment.

Prognosis

The dry form accounts for ninety percent of all cases of Age-related Macular Degeneration ( AMD ). Dry AMD progresses slowly, and patients keep most of their vision throughout life.

The wet form comprises ten percent of all cases of AMD. Wet AMD is a leading cause of irreversible legal blindness in patients older than 55 in the United States. Approximately 60% of those who lose vision in one eye lose vision in the other eye as well. When both eyes have wet AMD, quality of life can be severely affected. However, people rarely lose all of their vision from macular degeneration as the peripheral or side vision stays intact. Despite poor central vision, most people with macular degeneration are able to care for themselves and perform most of the activities of daily living.

Treatments for macular degeneration are constantly evolving. Research and a better understanding of the disease process have led to new treatments and better visual outcomes for patients with the “wet” form of the disease.

With today’s treatments, the visual prognosis for macular degeneration is better than it has ever been in the past.

MACULAR PUCKER/EPIRETINAL MEMBRANE:

The retina is a thin layer of nerve tissue that lines the inside of the eye. It functions to gather light and send visual information to the brain. The macula is the area of retina that is critical to central vision. Scar tissue can grow on the surface of the retina directly over the macula. This scar tissue can shrink and cause the retina to wrinkle. The scar tissue on the surface of the retina is called an epiretinal membrane or macular pucker. An epiretinal membrane can cause visual loss as well as distorted or double vision.

Epiretinal membranes occur more frequently in the older population with studies showing 2% prevalence in individuals aged 50 years and as much as 20% prevalence in individuals aged 75 years. Epiretinal membranes may be caused by a variety of eye problems. For example, they may follow retinal detachment surgery or treatment for retinal tears. They also may be associated with retinal blood vessel disease. However, in most cases an epiretinal membrane occurs in an otherwise healthy eye.

Surgical Treatment:

Surgical removal is the only treatment for the visual loss caused by an epiretinal membrane. However, if the vision is only mildly reduced, it is often best to observe the condition without surgery. If the visual loss or distortion is significant, a vitrectomy may be performed to remove the membrane. During the procedure, the surgeon uses fine instruments to carefully lift the membrane from the macula and gently peel it off the surface of the retina. This surgery is usually performed under local anesthesia.

Prognosis:

Studies have shown that between 65% and 90% of patients gain had at least 2 lines of vision when tested on the eye chart. In most cases, visual improvement following epiretinal membrane surgery occurs gradually as the eye heals. Usually there is some visual improvement in the first six weeks, but final visual recovery is not achieved in many patients until at least six months have passed since surgery. Once the macula has had a chance to completely heal and restore more normal function, a final prescription for glasses is given. For patients who have not had cataract surgery previously, the likelihood is high that a cataract will develop following epiretinal membrane surgery. If this does occur, the patient can begin to experience gradual visual reduction as the cataract develops—usually about 6-12 months following epiretinal membrane surgery. Once the cataract is removed, the vision usually returns to its pre-cataract level.

In a small number of cases, the epiretinal membrane may grow back as a result of reactivation of the surgical healing process. The reason that epiretinal membranes grow back in some patients and not in others is not well understood. In some cases, it appears that the body recognizes the surgical procedure itself as a form of injury or irritation to the retina and restarts the healing process that caused the epiretinal membrane in the first place. Fortunately, recurrence of epiretinal membranes is not common, and patients usually achieve stable vision after surgery.

MACULAR HOLE

The retina is a thin layer of nerve tissue that lines the inside of the eye. It functions to gather light and send visual information to the brain. The macula is the area of retina that is critical to central vision. A macular hole is a defect in the central retina.
Most macular holes are caused by localized pulling on the retina by the jelly (vitreous) that normally fills the entire back of the eye. Early on, this pulling may cause mild visual blur as the retina becomes thinner. If a complete hole develops, patients are usually aware of a blind spot or distortion of their central vision.Macular Hole

There are several different causes for macular holes. Chronic macular edema (i.e. diabetics) or trauma are two potential causes for macular holes. However, the overwhelming majority of macular holes develop spontaneously and have no underlying disease cause. Macular holes that have no underlying cause are called idiopathic macular holes.

Treatment:

During the past 10 years, surgery to treat macular holes has become increasingly common. The goal of the surgery is remove the jelly (vitreous) that is pulling on the macula. This is done using delicate surgical instruments under a microscope. After the vitreous is removed, the eye is then filled with a large gas bubble. The gas bubble slowly disappears from the eye spontaneously and usually lasts 2 weeks. This gas bubble provides a temporary seal to the macular hole and greatly increases the chance of successful surgery. If successful, some of the lost central vision may be restored.

The surgery itself is only one part of the formula for success. Assuming a face down position for the first 7days following surgery permits the bubble to float to the back of the eye and maintain gentle pressure on the macular hole. This keeps the hole completely closed and encourages retinal tissue to fill in the hole.

Prognosis:

In most cases, visual improvement following macular hole surgery occurs gradually as the eye heals. Usually there is some visual improvement in the first few months, and many patients will continue to show gradual visual improvement up to 2 years following surgery.

Once the macula has had a chance to completely heal, a final prescription for glasses is given. For patients who have not had cataract surgery previously, the likelihood is high that a cataract will develop following macular hole surgery. If this does occur, the patient can begin to experience gradual visual reduction as the cataract develops—usually about 6-12 months following macular hole surgery. Once the cataract is removed, the vision usually returns to its pre-cataract level.

In a small number of cases, a macular hole may reopen long after surgical recovery. The reason that macular holes recur is not well understood. In some cases, it may be beneficial to perform a second surgery to close the hole a second time.

DIABETIC RETINOPATHY

Diabetes mellitus is one of the leading causes of irreversible blindness worldwide. In the United States, it is the most common cause of blindness in people younger than 65 years. Severe diabetic eye disease most commonly develops in people who have had diabetes mellitus for many years.

High blood sugar and other abnormalities in metabolism found in people with diabetes mellitus can damage the blood vessels in the body. This damage to the blood vessels leads to poor circulation of blood to various parts of the body. Some of the most sensitive tissues to decreased blood flow and oxygen delivery include the feet, heart, kidneys, and eyes. The primary part of the eye affected by diabetes mellitus is the retina.

Diabetic RentinopathyThe better control diabetics have of their blood sugar, the fewer problems they will have in the long run. The most important method of preventing eye disease related to diabetes is to maintain strict control of blood sugar. High blood pressure and high lipid or cholesterol levels must also be treated as these conditions exacerbate the retinal disease caused by diabetes. In mild cases of diabetic eye disease, vision may be stable for many years. Eye surgery can also improve vision in many cases.

There are two major stages of diabetic retinopathy. The earlier stage of diabetic retinopathy is called non-proliferative diabetic retinopathy. The later, more advanced stage of diabetic retinopathy is called proliferative diabetic retinopathy.

Non-proliferative diabetic retinopathy

Damage to the walls of small blood vessels in the retina are caused by elevated blood sugar levels. These small blood vessels may begin to “break down” as damage accumulates with time. This leads to the accumulation of fluid (edema), protein deposits (hard exudates) and blood (hemorrhages) inside the retina. Diseased blood vessels will also develop thin walled pouches called microaneurysms, which are one of the earliest signs of diabetic eye disease.

This process of blood vessel damage and leakage in the retina is called background diabetic retinopathy or non-proliferative diabetic retinopathy. If fluid accumulates in the central part of the retina (called the macula), this leads to a condition called diabetic macular edema. In severe cases of blood vessel damage, the small capillaries that supply the center of the vision (macula) may close permanently. This condition is called macular ischemia.

Macular edema and macular ischemia are common causes of visual loss in diabetics. Central visual blur, visual distortion, and/or a blind spot are common symptoms in patients who have moderate to severe macular disease from non-proliferative diabetic retinopathy.

Many patients with non-proliferative diabetic retinopathy have the early stages of the disease and do not require treatment. However, scheduled retinal examinations by an eye doctor are always necessary for patients with diabetic retinopathy.

Proliferative diabetic retinopathy

Damage to the blood vessels caused by high blood sugar eventually leads to decreased blood flow and lower amounts of oxygen delivered to the retina. As a response to poor oxygen delivery to the retina, the body may create new blood vessels which grow on the retina’s surface. The process of new blood vessel formation is called retinal neovascularization.

Retinal neovascularization is the hallmark of proliferative diabetic retinopathy. While new blood vessels may sound like a good thing, they are actually more harmful than beneficial. The new blood vessels are extremely fragile and unstable. If left untreated, neovascularization can lead to bleeding and scar tissue formation inside the eye. This often results in severe vision loss. In advanced stages of the disease, this vision loss may be permanent. Early detection and treatment is important to prevent vision loss from proliferative diabetic retinopathy.

In severe cases, neovascularization can develop in the front of the eye on the iris (the colored part of the eye). If abnormal vessels develop on the iris, they can block the filter which drains fluid from the eye, causing the pressure inside the eye to increase dramatically. This condition is called neovascular glaucoma and can lead to eye pain and further vision loss.

Medical Treatment:

Medical treatment of diabetic eye disease is generally directed at the underlying problem – the diabetes itself. The better control diabetics have of their blood sugar, the fewer problems patients will have in the long run. The most important method of preventing eye disease related to diabetes is to maintain strict control of blood sugar. High blood pressure and high lipid or cholesterol levels must also be treated as these conditions exacerbate the retinopathy caused by diabetes.

Treatment of diabetic retinopathy may also include injection of medicines into the eye. These are called intravitreal injections. Recent studies have shown that certain drugs injected into the eye can reduce swelling of the retina and reverse retinal neovascularization. Even though injections can be very helpful, usually additional treatments are necessary to achieve the best long term results.

Surgical treatment:

Non-proliferative diabetic retinopathy is treated with laser when swelling of the central retina develops. Swelling of the central retina occurs when diseased blood vessels in the retina begin to leak fluid or lipids. Fluid begins to accumulate in the retina causing thickening and distortion of the retinal layers. This results in blurred or distorted vision. This condition is called diabetic macular edema.

Diabetic macular edema is treated with a laser technique called macular photocoagulation. This laser treatment is performed in the office and involves focusing a beam of laser light to treat leaking blood vessels and areas of retinal swelling. Macular photocoagulation has been proven to reduce the risk of vision loss due to macula edema.

Proliferative diabetic retinopathy is treated with both laser and operating room surgery. Pan-retinal photocoagulation (PRP) is the laser technique performed to treat neovascularization of the retina. During this treatment the majority of the peripheral retina is treated with laser spots to promote regression of neovascular tissue. Pan-retinal photocoagulation has been proven to reduce the risk of vision loss due to proliferative diabetic retinopathy.

If extensive new blood vessel growth, scar tissue formation, or bleeding inside the eye has already occurred, a surgical procedure known as a vitrectomy may be recommended. This surgery is performed in an operating room at a hospital or ambulatory surgery center. The vitreous (a gel-like fluid) and the blood inside the eye are removed and replaced with a clear fluid. Scar tissue is also removed from the retinal surface during a vitrectomy when necessary. A vitrectomy surgery is often combined with laser treatment and/or retinal detachment surgery.

Prognosis:

The earlier diabetic eye disease is diagnosed and treated (if necessary), the better the prognosis. For those with diabetic retinopathy, the prognosis is determined by the severity of the disease. In mild cases and in those treated early, vision may be stable for many years and eye surgery can improve vision in many cases. In severe cases, relentless and progressive irreversible vision loss may occur despite the best treatment. If you have diabetes mellitus, “an ounce of prevention is worth a pound of cure.” Following the advice of your medical doctor in regards to proper diet and exercise, blood sugar monitoring, and taking diabetic medication, the chances of developing serious problems from diabetes decrease dramatically.

FLASHES AND FLOATERS:

Most of the eye's interior is filled with vitreous, a gel-like substance that is very thick when we are young. There are millions of fine fibers intertwined within the vitreous that are attached to the surface of the retina, which lines the inside of the eye. As we age, the vitreous slowly liquefies and begins to pull away from the retina as the gel collapses upon itself. Separation of the vitreous from the retina can happen rather suddenly. When the separation occurs, the fibers inside the vitreous can become dense and visible. These fibers appear as "floaters", often described as black spots or cobwebs floating in one's field of vision. These floaters may also be accompanied by "flashes" of light (lightning streaks) in one's peripheral, or side, vision. These flashes are caused by a pulling effect or traction that the vitreous has on the retina (the light sensitive part of the eye) as it separates from the retina. This mechanical pulling stimulates the retinal nerve cell to send an electrical signal to the brain. The brain interprets this signal as light, even though no light is there.

This entire process is called a vitreous detachment or separation. In most cases, a vitreous detachment is not sight-threatening and requires no treatment. A vitreous detachment is a common condition that usually affects people over age 50, and is very common after age 80. People who are nearsighted are also at increased risk. Those who have a vitreous detachment in one eye are likely to have one in the other, although it may not happen until years later. In most cases, either you will not notice a vitreous detachment, or you will find it merely annoying because of the increase in floaters.

Although a vitreous detachment does not threaten sight, once in a while some of the vitreous fibers pull so hard on the retina that they tear the retina leading to a retinal detachment. This is a sight-threatening condition and should be treated immediately. If left untreated, a detached retina can lead to permanent vision loss in the affected eye. Those who experience a sudden increase in floaters or flashes of light should have an eye care professional examine their eyes as soon as possible. The only way to diagnose the cause of the problem is by a comprehensive dilated eye examination. If the vitreous detachment has led to a retinal tear or detachment, early treatment can help prevent loss of vision.

RETINAL TEARS/DETACHMENT:

Retinal detachment is a sight threatening condition that is considered one of the few ocular emergencies. A retinal detachment can occur at any age, but it is more common in people over age 40. It affects men more than women. It is estimated that 1 in 10,000 people develop a retinal detachment.

The retina a thin layer of nerve tissue which lines the inside of the eye. This nerve layer is analogous to the "film inside a camera" and is essential for sight. In certain abnormal conditions, the retina may separate from the inside wall of the eye and hang freely within the middle of the eye. This is called a retinal detachment.

The most common sequence of events leading to a retinal detachment begins with the sudden collapse of the vitreous gel that fills the middle of the eye. When the vitreous gel collapses, this is called a vitreous detachment. When a person develops a vitreous detachment they commonly see floaters and flashes in their vision. A posterior vitreous separation occurs suddenly and without a proximal cause in most patients.

Retinal DetachmentAs the vitreous separates, it may pull on the retina hard enough to cause the retina to tear. Retinal tears allow fluid to pass though the retina and move behind the retinal layer. As fluid accumulates behind the retina, it moves further away from the wall of the eye. This condition is called a retinal detachment and can result in severe loss of vision. One of the most ominous symptoms of a retinal detachment is a "curtain" coming over the field of vision.

Treatment:

Retinal detachments and retinal tears are treated with surgery. The type of operation depends on the nature of the retinal detachment.

Retinal laser or retinal cryotherapy: Retinal tears and holes can be treated with laser surgery or a freeze treatment called cryotherapy. These procedures are usually performed in the doctor's office. During laser surgery tiny burns are made around the hole to "weld" the retina back into place. Cryotherapy freezes the area around the hole and helps reattach the retina.
Pneumatic retinopexy: A small gas bubble is injected into the eye which pushes the retina back against the wall of the eye. In addition, laser or cryotherapy is used to seal the retinal tear and help hold the retina in place. This surgery is performed in an office setting under topical or local anesthesia. This operation is less invasive than scleral buckle or vitrectomy. However, no all patients will be good candidates for this operation.
Scleral buckle: A tiny synthetic band, is attached to the outside of the eyeball to gently push the wall of the eye against the detached retina. During this procedure, cryotherapy is applied to the retina to help to help hold the retina in place. This surgery is performed in an operating room under local anesthesia with sedation.


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