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Retinal Disorders

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Retinal Disorders

The information provided in this Resource Guide was developed by the National Eye Institute (NEI) to help patients and their families search for general information about retinal diseases. An eye care professional who has examined the patient's eyes and is familiar with his or her medical history is the best person to answer specific questions.

Macular Hole

Macular Pucker

Age-related Macular Degeneration (AMD) Defined

Retinal Detachment

Facts About Floaters

What is Retinitis Pigmentosa?

Uveitis: A Closer Look

Diabetic Retinopathy

Retinal Artery and Vein Occlusion

Central Retinal Artery and Vein Occlusions

Retinopathy of Prematurity

Vitreous Detachment

Macular Hole

Other Names:
Macular cyst, retinal hole, retinal tear, and retinal perforation.

What is a macular hole?
A macular hole is a small break in the macula, located in the center of the eye's light-sensitive tissue called the retina. The macula provides the sharp, central vision we need for reading, driving, and seeing fine detail.

A macular hole can cause blurred and distorted central vision. Macular holes are related to aging and usually occur in people over age 60.

Retina

Is a macular hole the same as age-related macular degeneration?
No. Macular holes and age-related macular degeneration are two separate and distinct conditions, although the symptoms for each are similar. Both conditions are common in people 60 and over. An eye care professional will know the difference.

What causes a macular hole?
Most of the eye's interior is filled with vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. The vitreous contains millions of fine fibers that are attached to the surface of the retina. As we age, the vitreous slowly shrinks and pulls away from the retinal surface. Natural fluids fill the area where the vitreous has contracted. This is normal. In most cases, there are no adverse effects. Some patients may experience a small increase in floaters, which are little "cobwebs" or specks that seem to float about in your field of vision.

However, if the vitreous is firmly attached to the retina when it pulls away, it can tear the retina and create a macular hole. Also, once the vitreous has pulled away from the surface of the retina, some of the fibers can remain on the retinal surface and can contract. This increases tension on the retina and can lead to a macular hole. In either case, the fluid that has replaced the shrunken vitreous can then seep through the hole onto the macula, blurring and distorting central vision.

Macular holes can also occur from eye disorders, such as high myopia (nearsightedness), macular pucker, and retinal detachment; eye disease, such diabetic retinopathy and Best's disease; and injury to the eye.

What are the symptoms of a macular hole?
Macular holes often begin gradually. In the early stage of a macular hole, people may notice a slight distortion or blurriness in their straight-ahead vision. Straight lines or objects can begin to look bent or wavy. Reading and performing other routine tasks with the affected eye become difficult.

Are there different types of a macular hole?
Yes. There are three stages to a macular hole:

Foveal detachments (Stage I). Without treatment, about half of Stage I macular holes will progress.
Partial-thickness holes (Stage II). Without treatment, about 70 percent of Stage II macular holes will progress.
Full-thickness holes (Stage III).

The size of the hole and its location on the retina determine how much it will affect a person's vision. When a Stage III macular hole develops, most central and detailed vision can be lost. If left untreated, a macular hole can lead to a detached retina, a sight-threatening condition that should receive immediate medical attention.

How is a macular hole treated?
Although some macular holes can seal themselves and require no treatment, surgery is necessary in many cases to help improve vision. In this surgical procedure--called a vitrectomy--the vitreous gel is removed to prevent it from pulling on the retina and replaced with a bubble containing a mixture of air and gas. The bubble acts as an internal, temporary bandage that holds the edge of the macular hole in place as it heals. Surgery is performed under local anesthesia and often on an out-patient basis.

Following surgery, patients must remain in a face-down position, normally for a day or two but sometimes for as long as two-to-three weeks. This position allows the bubble to press against the macula and be gradually reabsorbed by the eye, sealing the hole. As the bubble is reabsorbed, the vitreous cavity refills with natural eye fluids.

Maintaining a face-down position is crucial to the success of the surgery. Because this position can be difficult for many people, it is important to discuss this with your doctor before surgery.

What are the risks of surgery?
The most common risk following macular hole surgery is an increase in the rate of cataract development. In most patients, a cataract can progress rapidly, and often becomes severe enough to require removal. Other less common complications include infection and retinal detachment either during surgery or afterward, both of which can be immediately treated. For a few months after surgery, patients are not permitted to travel by air. Changes in air pressure may cause the bubble in the eye to expand, increasing pressure inside the eye.

How successful is this surgery?
Vision improvement varies from patient to patient. People that have had a macular hole for less than six months have a better chance of recovering vision than those who have had one for a longer period. Discuss vision recovery with your doctor before your surgery. Vision recovery can continue for as long as three months after surgery.

What if I cannot remain in a face-down position after the surgery?
If you cannot remain in a face-down position for the required period after surgery, vision recovery may not be successful. People who are unable to remain in a face-down position for this length of time may not be good candidates for a vitrectomy. However, there are a number of devices that can make the "face-down" recovery period easier on you. There are also some approaches that can decrease the amount of "face-down" time. Discuss these with your doctor.

Is my other eye at risk?
If a macular hole exists in one eye, there is a 10-15 percent chance that a macular hole will develop in your other eye over your lifetime. Your doctor can discuss this with you.

Research
Research studies are being conducted to determine other treatments for macular holes. Currently the research is looking at using silicon oil to close the macular hole instead of the gas bubble that is being used now. No definite conclusions have been reached at this time.

Other Resources
The following organization may be able to provide additional information on macular holes:

American Academy of Ophthalmology

http://www.aao.org

Association for Macular Diseases

http://www.macula.org

(The) Foundation Fighting Blindness

http://www.blindness.org

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Macular Pucker

Other Names:
Epiretinal membrane, preretinal membrane, cellophane maculopathy, retina wrinkle, surface wrinkling retinopathy, premacular fibrosis, and internal limiting membrane disease.

What is a macular pucker?
A macular pucker is scar tissue that has formed on the eye's macula, located in the center of the eye's light-sensitive tissue called the retina. The macula provides the sharp, central vision we need for reading, driving, and seeing fine detail. A macular pucker can cause blurred and distorted central vision.

Most of the eye's interior is filled with vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape. The vitreous contains millions of fine fibers that are attached to the surface of the retina. As we age, the vitreous slowly shrinks and pulls away from the retinal surface. This is called a vitreous detachment, and is normal. In most cases, there are no adverse effects, except for a small increase in floaters, which are little "cobwebs" or specks that seem to float about in your field of vision.

However, sometimes when the vitreous pulls away from the retina, there is microscopic damage to the retina's surface (Note: This is not a macular hole). When this happens, the retina begins a healing process to the damaged area and forms scar tissue, or an epiretinal membrane, on the surface of the retina. This scar tissue is firmly attached to the retina surface. When the scar tissue contracts, it causes the retina to wrinkle, or pucker, usually without any effect on central vision. However, if the scar tissue has formed over the macula, our sharp, central vision becomes blurred and distorted.

What causes a macular pucker?
Most macular puckers are related to vitreous detachment, which usually occurs in people over age 50. As you age, you are at increased risk for macular pucker.

A macular pucker can also be triggered by certain eye diseases and disorders, such as a detached retina and inflammation of the eye (uveitis). Also, people with diabetes sometimes develop an eye disease called diabetic retinopathy, which can cause a macular pucker. A macular pucker can also be caused by trauma from either surgery or an eye injury.

What are the symptoms of a macular pucker?
Vision loss from a macular pucker can vary from no loss to severe loss, although severe vision loss is uncommon. People with a macular pucker may notice that their vision is blurry or mildly distorted, and straight lines can appear wavy. They may have difficulty in seeing fine detail and reading small print. There may be a gray area in the center of your vision, or perhaps even a blind spot.

Is a macular pucker the same as age-relaed macular degeneration?
No. A macular pucker and age-related macular degeneration are two separate and distinct conditions, although the symptoms for each are similar. An eye care professional will know the difference.

Can macular pucker get worse?
For most people, vision remains stable and does not get progressively worse. Usually macular pucker affects one eye, although it may affect the other eye later.

Is a macular pucker similar to a macular hole?
A macular pucker and a macular hole are different conditions, although they both result from the same reason: The pulling on the retina from a shrinking vitreous. When the "pulling" causes microscopic damage, the retina can heal itself; scar tissue, or a macular pucker, can be the result. If the shrinking vitreous pulls too hard, it can tear the retina, creating a macular hole, which is more serious. Both conditions have similar symptoms - distorted and blurred vision. Also, a macular pucker will not "develop" into a macular hole. An eye care professional will know the difference.

How is a macular pucker treated?
A macular pucker usually requires no treatment. In many cases, the symptoms of vision distortion and blurriness are mild, and no treatment is necessary. People usually adjust to the mild visual distortion, since it does not affect activities of daily life, such as reading and driving. Neither eye drops, medications, nor nutritional supplements will improve vision distorted from macular pucker. Sometimes the scar tissue--which causes a macular pucker--separates from the retina, and the macular pucker clears up.

Rarely, vision deteriorates to the point where it affects daily routine activities. However, when this happens, surgery may be recommended. This procedure is called a vitrectomy, in which the vitreous gel is removed to prevent it from pulling on the retina and replaced with a salt solution (Because the vitreous is mostly water, you will notice no change between the salt solution and the normal vitreous). Also, the scar tissue which causes the wrinkling is removed. A vitrectomy is usually performed under local anesthesia.

After the operation, you will need to wear an eye patch for a few days or weeks to protect the eye. You will also need to use medicated eye drops to protect against infection.

How successful is this surgery?
Surgery to repair a macular pucker is very delicate, and while vision improves in most cases, it does not usually return to normal. On average, about half of the vision lost from a macular pucker is restored; some people have significantly more vision restored, some less. In most cases, vision distortion is significantly reduced. Recovery of vision can take up to three months. Patients should talk with their eye care professional about whether treatment is appropriate.

What are the risks of surgery?
The most common complication of a vitrectomy is an increase in the rate of cataract development. Cataract surgery may be needed within a few years after the vitrectomy. Other, less common complications are retinal detachment either during or after surgery, and infection after surgery. Also, the macular pucker may grow back, but this is rare.

Research
Research studies are being conducted to determine other treatments for macular pucker. Please note that both of the procedures described below need additional clinical testing. We suggest you share this information with your eye care professional.

Some physicians are researching the use of a surgical procedure in which scar tissue is peeled off without performing the vitrectomy.

Other doctors are researching a new surgical technique to remove the internal limiting membrane (a layer of the retina) for patients with both macular pucker and macular hole. This surgical technique is called Fluidic Internal Limiting Membrane Separation (FILMS). After a vitrectomy, fluid is injected between the membrane and the retina that causes the membrane, along with the scar tissue, to lift away. It is then removed with forceps.

Other Resources
The following organizations may be able to provide additional information on macular pucker:

Association for Macular Diseases

http://www.macula.org

(The) Foundation Fighting Blindness

http://www.blindness.org

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Age-related Macular Degeneration (AMD) Defined

1. What is age-related macular degeneration?
Age-related macular degeneration, or AMD, is a disease that blurs the sharp, central vision you need for straight-ahead activities such as reading, sewing, and driving. AMD affects the macula, the part of the eye that allows you to see fine detail. AMD causes no pain.

2. Are there different forms of AMD?
Yes. AMD occurs in two forms -- wet and dry.

3. What is wet AMD?
Wet AMD occurs when abnormal blood vessels behind the retina start to grow under the macula. With wet AMD, loss of central vision can occur quickly. Wet AMD is considered to be advanced AMD and is more severe than the dry form.

4. What is dry AMD?
Dry AMD occurs when the light-sensitive cells in the macula slowly break down, gradually blurring central vision in the affected eye. As dry AMD gets worse, you may see a blurred spot in the center of your vision. Over time, as less of the macula functions, central vision in the affected eye can be lost.

If you have vision loss from dry AMD in one eye only, you may not notice any changes in your overall vision.

With the other eye seeing clearly, you can still drive, read, and see fine details. You may notice changes in your vision only if AMD affects both eyes. If you experience blurry vision, see an eye care professional for a comprehensive dilated eye exam.

5. What are the stages of dry AMD?
Dry AMD has three stages -- early AMD, intermediate AMD, and advanced dry AMD. All of these may occur in one or both eyes.

People with early dry AMD have either several small drusen or a few medium-sized drusen. Drusen are yellow deposits under the retina which often are found in people over age 60.

People with early AMD have no symptoms and no vision loss.

People with intermediate dry AMD have either many medium-sized drusen or one or more large drusen. Some people see a blurred spot in the center of their vision. More light may be needed for reading and other tasks.

In addition to drusen, people with advanced dry AMD have a breakdown of light-sensitive cells and supporting tissue in the macula. This breakdown can cause a blurred spot in the center of your vision.

Over time, the blurred spot may get bigger and darker, taking more of your central vision. You may have difficulty reading or recognizing faces until they are very close to you.

6. What are drusen?
Drusen are yellow deposits under the retina. They often are found in people over age 60. Your eye care professional can detect drusen during a comprehensive dilated eye exam.

7. Do drusen cause vision loss in advanced dry AMD?
Drusen alone do not usually cause vision loss. In fact, scientists are unclear about the connection between drusen and AMD. They do know that an increase in the size or number of drusen raises a person's risk of developing either advanced dry AMD or wet AMD. These changes can cause serious vision loss.

8. The dry form of AMD has early and intermediate stages. Does the wet form have similar stages?
No. The wet form is considered advanced AMD.

9. Can advanced AMD be either the dry form or the wet form?
Yes. Both the wet form and the advanced dry form are considered advanced AMD. Vision loss occurs with either form. In most cases, only advanced AMD can cause vision loss.

10. Can the dry form turn into the wet form?
Yes. All people who have the wet form had the dry form first. The dry form can advance and cause vision loss without turning into the wet form. The dry form also can suddenly turn into the wet form, even during early stage AMD. There is no way to tell if or when the dry form will turn into the wet form.

11. What are the symptoms of wet AMD?
An early symptom of wet AMD is that straight lines appear wavy. If you notice this condition or other changes to your vision, contact your eye care professional at once. You need a comprehensive dilated eye exam.

12. What are the symptoms of dry AMD?
The most common symptom of dry AMD is slightly blurred vision. You may have difficulty recognizing faces. You may need more light for reading and other tasks. Dry AMD generally affects both eyes, but vision can be lost in one eye while the other eye seems unaffected. One of the most common early signs of dry AMD is drusen. Drusen are yellow deposits under the retina. They often are found in people over age 60. Your eye care professional can detect drusen during a comprehensive dilated eye exam.

13. Who is at risk for AMD?
AMD is most common in older people, but it can occur during middle age. The risk increases with age. Other risk factors include smoking, obesity, white race, family history of AMD, and female gender.

14. How is AMD detected?
AMD is detected during a comprehensive eye exam that includes a visual acuity test, dilated eye exam, and tonometry.

The visual acuity test is an eye chart test that measures how well you see at various distances. In the 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 AMD and other eye problems. After the exam, your close-up vision may remain blurred for several hours.

With tonometry, an instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.

15. How is dry AMD treated?
Once dry AMD reaches the advanced stage, no form of treatment can prevent vision loss. However, treatment can delay and possibly prevent intermediate AMD from progressing to the advanced stage, in which vision loss occurs.

16. What is the AREDS formulation?
The AREDS formulation is a combination of antioxidants and zinc that is named for a study conducted by The National Eye Institute called the Age-Related Eye Disease Study, or AREDS. This study found that taking a specific high-dose formulation of antioxidants and zinc significantly reduced the risk of advanced AMD and its associated vision loss. Slowing AMD's progression from the intermediate stage to the advanced stage will save many people's vision.

17. What is the dosage of the AREDS formulation?
The daily amounts used by the study researchers were 500 milligrams of vitamin C, 400 International Units of vitamin E, 15 milligrams of beta-carotene, 80 milligrams of zinc as zinc oxide, and 2 milligrams of copper as cupric oxide. Copper was added to the AREDS formulation containing zinc to prevent copper deficiency anemia, a condition associated with high levels of zinc intake.

18. Who should take the AREDS formulation?
People who are at high risk for developing advanced AMD should consider taking the formulation. You are at high risk for developing advanced AMD if you have either intermediate AMD in one or both eyes OR advanced AMD, dry or wet, in one eye but not the other eye. Your eye care professional can tell you if you have AMD, its stage, and your risk for developing the advanced form. The AREDS formulation is not a cure for AMD. It will not restore vision already lost from the disease. However, it may delay the onset of advanced AMD. It may help people who are at high risk for developing advanced AMD keep their vision.

19. Can people with early stage AMD take the AREDS formulation to help prevent the disease from progressing to the intermediate stage?
There is no reason for those diagnosed with early stage AMD to take the AREDS formulation. The study did not find that the formulation helped those with early stage AMD.

If you have early stage AMD, a comprehensive dilated eye exam every year can help determine if the disease is progressing. If early stage AMD progresses to the intermediate stage, discuss taking the formulation with your doctor.

20. How is wet AMD treated?
Wet AMD can be treated with laser surgery, photodynamic therapy, and drugs that are injected into the eye. None of these treatments is a cure for wet AMD. The disease and loss of vision may progress despite treatment.

21. What can I do if I already have lost some vision from AMD?
If you have lost some sight from AMD, ask your eye care professional about low vision services and devices that may help you make the most of your remaining vision.

Ask for a referral to a specialist in low vision. Many community organizations and agencies offer information about low vision counseling, training, and other special services for people with visual impairments

Don't be afraid to use your eyes for reading, watching TV, and other routine activities. Normal use of your eyes will not cause further damage to your vision.

22. What research is being done?
The National Eye Institute scientists are studying the possibility of transplanting healthy cells into a diseased retina evaluating families with a history of AMD to understand genetic and hereditary factors that may cause the disease looking at certain anti-inflammatory treatments for the wet form of AMD. This research should provide better ways to detect, treat, and prevent vision loss in people with AMD.

23. What can I do to protect my vision?
You should have a comprehensive dilated eye exam at least once a year. Your eye care professional can monitor your condition and check for other eye diseases. You may also be advised to take the AREDS supplementation.

During an eye exam, you may be asked to look at an Amsler grid, shown here. You will cover one eye and stare at a black dot in the center of the grid.

While staring at the dot, you may notice that the straight lines in the pattern appear wavy. You may notice that some of the lines are missing. These may be signs of AMD.

Because dry AMD can turn into wet AMD at any time, you should get an Amsler grid from your eye care professional. You could then use the grid every day to evaluate your vision for signs of wet AMD.

24. Can my lifestyle make a difference?
Your lifestyle can play a role in reducing your risk of developing AMD.

Eat a healthy diet high in green leafy vegetables and fish.
Don't smoke.
Maintain normal blood pressure.
Watch your weight.
Exercise.

Association for Macular Diseases

http://www.macula.org

National Eye Institute
National Institutes of Health

www.nei.nih.gov

Association for Macular Diseases

Foundation Fighting Blindness

Macular Degeneration Partnership

Topic last updated: 24 October 2006

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Retinal Detachment

Other Names
Detached retina, and retinal tear.

What is retinal detachment?
The retina is the light-sensitive layer of tissue that lines the inside of the eye and sends visual messages through the optic nerve to the brain. When the retina detaches, it is lifted or pulled from its normal position. If not promptly treated, retinal detachment can cause permanent vision loss.

In some cases there may be small areas of the retina that are torn. These areas, called retinal tears or retinal breaks, can lead to retinal detachment.

What are the symptoms of retinal detachment?
Symptoms include a sudden or gradual increase in either the number of floaters, which are little "cobwebs" or specks that float about in your field of vision, and/or light flashes in the eye. Another symptom is the appearance of a curtain over the field of vision. A retinal detachment is a medical emergency. Anyone experiencing the symptoms of a retinal detachment should see an eye care professional immediately.

What are the different types of retinal detachment?
There are three different types of retinal detachment:

Rhegmatogenous [reg-ma-TAH-jenous] -- A tear or break in the retina allows fluid to get under the retina and separate it from the retinal pigment epithelium (RPE), the pigmented cell layer that nourishes the retina. These types of retinal detachments are the most common.
Tractional -- In this type of detachment, scar tissue on the retina's surface contracts and causes the retina to separate from the RPE. This type of detachment is less common.
Exudative -- Frequently caused by retinal diseases, including inflammatory disorders and injury/trauma to the eye. In this type, fluid leaks into the area underneath the retina, but there are no tears or breaks in the retina.

Who is at risk for retinal detachment?
A retinal detachment can occur at any age, but it is more common in people over age 40. It affects men more than women, and Whites more than African Americans.

A retinal detachment is also more likely to occur in people who:

Are extremely nearsighted
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

How is retinal detachment treated?
Small holes and tears are treated with laser surgery or a freeze treatment called cryopexy. 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. Cryopexy freezes the area around the hole and helps reattach the retina.

Retinal detachments are treated with surgery that may require the patient to stay in the hospital. In some cases a 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. If necessary, a vitrectomy may also be performed. During a vitrectomy, the doctor makes a tiny incision in the sclera (white of the eye). Next, a small instrument is placed into the eye to remove the vitreous, a gel-like substance that fills the center of the eye and helps the eye maintain a round shape. Gas is often injected to into the eye to replace the vitreous and reattach the retina; the gas pushes the retina back against the wall of the eye. During the healing process, the eye makes fluid that gradually replaces the gas and fills the eye. With all of these procedures, either laser or cryopexy is used to "weld" the retina back in place.

With modern therapy, over 90 percent of those with a retinal detachment can be successfully treated, although sometimes a second treatment is needed. However, the visual outcome is not always predictable. The final visual result may not be known for up to several months following surgery. Even under the best of circumstances, and even after multiple attempts at repair, treatment sometimes fails and vision may eventually be lost. Visual results are best if the retinal detachment is repaired before the macula (the center region of the retina responsible for fine, detailed vision) detaches. That is why it is important to contact an eye care professional immediately if you see a sudden or gradual increase in the number of floaters and/or light flashes, or a dark curtain over the field of vision.

National Eye Institute-Supported Research
The NEI supported The Silicone Study, a nationwide clinical trial that compared the use of silicone oil with long-acting intraocular gas for repairing a retinal detachment caused by proliferative vitreoretinopathy (PVR). With PVR, cells grow on the surface of the retina causing it to detach. This is a serious complication that sometimes follows retinal detachment surgery and is difficult to treat. The results indicate that both treatments are effective and give the surgeons more options for treating these difficult cases. More information on The Silicone Study is available at http://www.nei.nih.gov/neitrials/static/study39.asp.

Other Resources
The following organizations may be able to provide additional information on retinal detachment:

National Eye Institute (NEI)

http://www.nei.nih.gov

National Marfan Foundation

http://www.marfan.org

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Facts About Floaters

Floaters are little "cobwebs" or specks that float about in your field of vision. They are small, dark, shadowy shapes that can look like spots, thread-like strands, or squiggly lines. They move as your eyes move and seem to dart away when you try to look at them directly. They do not follow your eye movements precisely, and usually drift when your eyes stop moving.

In most cases, floaters are part of the natural aging process and simply an annoyance. They can be distracting at first, but eventually tend to "settle" at the bottom of the eye, becoming less bothersome. They usually settle below the line of sight and do not go away completely. Most people have floaters and learn to ignore them; they are usually not noticed until they become numerous or more prominent. Floaters can become apparent when looking at something bright, such as white paper or a blue sky.

Floaters occur when the vitreous, a gel-like substance that fills about 80 percent of the eye and helps it maintain a round shape, slowly shrinks. As the vitreous shrinks, it becomes somewhat stringy, and the strands can cast tiny shadows on the retina. These are floaters.

Floaters are more likely to develop as we age and are more common in people who are very nearsighted, have diabetes, or who have had a cataract operation. There are other, more serious causes of floaters, including infection, inflammation (uveitis), hemorrhaging, retinal tears, and injury to the eye.

Sometimes a section of the vitreous pulls the fine fibers away from the retina all at once, rather than gradually, causing many new floaters to appear suddenly. This is called a vitreous detachment, which in most cases is not sight-threatening and requires no treatment. However, a sudden increase in floaters, possibly accompanied by light flashes or peripheral (side) vision loss, could indicate a retinal detachment. A retinal detachment occurs when any part of the retina, the eye's light-sensitive tissue, is lifted or pulled from its normal position at the back wall of the eye. A retinal detachment is a serious condition and should always be considered an emergency. If left untreated, it can lead to permanent visual impairment within two or three days or even blindness in the eye. Those who experience a sudden increase in floaters, flashes of light in peripheral vision, or a loss of peripheral vision should have an eye care professional examine their eyes as soon as possible.

For people who have floaters that are simply annoying, no treatment is recommended. On rare occasions, floaters can be so dense and numerous that they significantly affect vision. In these cases, a vitrectomy, a surgical procedure that removes floaters from the vitreous, may be needed. A vitrectomy removes the vitreous gel, along with its floating debris, from the eye. The vitreous is replaced with a salt solution. Because the vitreous is mostly water, you will not notice any change between the salt solution and the original vitreous. This operation carries significant risks to sight because of possible complications, which include retinal detachment, retinal tears, and cataract. Most eye surgeons are reluctant to recommend this surgery unless the floaters seriously interfere with vision.

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What is Retinitis Pigmentosa?

Retinitis pigmentosa (RP) is the name given to a group of inherited eye diseases that affect the retina. Retinitis pigmentosa causes the degeneration of photoreceptor cells in the retina. Photoreceptor cells capture and process light helping us to see. As these cells degenerate and die, patients experience progressive vision loss.

Symptoms
The most common feature of all forms of Retinitis Pigmentosa is a gradual degeneration of the rods and cones. Most forms of RP first cause the degeneration of rod cells. These forms of Retinitis pigmentosa, sometimes called rod-cone dystrophy, usually begin with night blindness. Night blindness is somewhat like the experience normally sighted individuals encounter when entering a dark movie theatre on a bright, sunny day. However, patients with Retinitis pigmentosa cannot adjust well to dark and dimly lit environments.

As the disease progresses and more rod cells degenerate, patients lose their peripheral vision. Patients with Retinitis Pigmentosa often experience a ring of vision loss in their mid-periphery with small islands of vision in their very far periphery. Others report the sensation of tunnel vision, as though they see the world through a straw. Many patients with Retinitis Pigmentosa retain a small degree of central vision throughout their life.


Normal vision	As seen by a person with retinitis pigmentosa

Other forms of Retinitis Pigmentosa, sometimes called cone-rod dystrophy, first affect central vision. Patients first experience a loss of central vision that cannot be corrected with glasses or contact lenses. With the loss of cone cells also comes disturbances in color perception. As the disease progresses, rod cells degenerate causing night blindness and peripheral vision.

Symptoms of Retinitis Pigmentosa are most often recognized in children, adolescents and young adults, with progression of the disease continuing throughout the individuals life. The pattern and degree of visual loss are variable.

Genetics of RP
Within the nucleus of every human cell reside a host of genes. Genes are the fundamental building blocks of life. Inherited from our parents, genes carry family traits like eye and hair color, the shape of our face and even diseases like Retinitis Pigmentosa.

Genes are like computer programs containing sets of coded instructions. Each gene instructs the cell to create a specialized protein that performs a specific task for the cell. In retinal cells, some genes encode proteins that allow the cell to process light. Other genes encode proteins that uptake nutrients and eliminate waste from the cell. Still other genes encode proteins that form the cell walls and other structures within the cell.

Sometimes, the coded instructions within a gene become altered. These alterations, known as mutations, can confer a benefit, allowing the organism to better adapt to its environment. However, mutations can also interfere with the proper encoding of a protein. The resultant protein cannot perform its job within the cell, thereby hampering the cells well being and leading to disease.

Retinal cells are among the most specialized cells in the human body and depend on a number of unique genes to create vision. A disease-causing mutation in any one of these genes can lead to vision loss. To date, Foundation researchers have discovered over 100 genes that can contain mutations leading to Retinitis Pigmentosa.

Retinitis Pigmentosa can be passed to succeeding generations by one of three genetic inheritance patterns-autosomal dominant, autosomal recessive, or X-linked inheritance.

Each type of inheritance causes a different pattern of affected and unaffected family members. For example, in families with autosomal recessive Retinitis Pigmentosa, unaffected parents can have both affected and unaffected children. In recessive Retinitis Pigmentosa, there is often no prior family history. In families with the autosomal dominant RP, an affected parent can have both affected and unaffected children. In families with the X-linked type, only males are affected, while females carry the genetic trait but do not experience serious vision loss. It is very important to remember that because RP is an inherited disorder, it can potentially affect another member of the family. If one member of a family is diagnosed with a hereditary retinal degeneration, it is strongly advised that all members of that family contact an ophthalmologist.

Related diseases
Other inherited diseases share some of the clinical symptoms of RP. Some of these conditions are complicated by other symptoms besides loss of vision. The most common of these is Usher syndrome, which causes both hearing and vision loss. Other rare syndromes that researchers are studying with funding from The Foundation Fighting Blindness include Bardet-Biedl (Laurence-Moon) syndrome, Best disease, choroideremia, gyrate-atrophy, Leber congenital amaurosis, and Stargardt disease.

RP and related diseases are rare and difficult to accurately diagnose. Only a specialist can properly distinguish between the subtle clinical features of these diseases. Therefore, it is important that patients who are symptomatic see an ophthalmologist who specializes in retinal degenerative diseases.

Images courtesy of the National Eye Institute, NIH
© 2006 Foundation Fighting Blindness

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Uveitis: A Closer Look

What Is Uveitis?
The eye is shaped much like a tennis ball, with three different layers of tissue surrounding the central gel-filled cavity.

The innermost layer is the retina, which senses light and helps to send images to your brain.

The middle layer between the sclera and retina is called the uvea. The outermost layer is the sclera, the strong white wall of the eye. Uveitis (pronounced you-vee-EYE-tis) is inflammation of the uvea.

Uveitis

What Is the Importance of the Uvea?
The uvea contains many blood vessels - the veins, arteries and capillaries - that carry blood to and from the eye. Since the uvea nourishes many important parts of the eye (such as the retina), inflammation of the uvea can damage your sight.

What Are the Symptoms of Uveitis?
Symptoms of uveitis include:

Light sensitivity
Blurred vision
Pain
Floaters
Redness of the eye

Uveitis may develop suddenly with redness and pain or with a painless blurring of your vision. A case of simple "red eye" may in fact be a serious problem of uveitis. If your eye becomes red or painful, you should be examined and treated by an ophthalmologist (Eye M.D.).

What Causes Uveitis? Uveitis has many different causes:

A virus, such as shingles, mumps or herpes simplex
A fungus, such as histoplasmosis
A parasite, such as toxoplasmosis
A related disease in other parts of the body, such as arthritis, gastrointestinal disease or collagen vascular disease such as lupus
A result of injury to the eye.

In most cases of uveitis, the cause of the disease remains unknown.

How Is Uveitis Diagnosed? A careful eye examination by an ophthalmologist is extremely important when symptoms occur. Inflammation inside the eye can permanently affect sight or even lead to blindness if it is not treated.

Your ophthalmologist will examine the inside of your eye. He or she may order blood tests, skin tests or x-rays to help make the diagnosis.

Since uveitis can be associated with disease in other parts of the body, your ophthalmologist will want to know about your overall health. He or she may want to consult with your primary care physician or other medical specialists.

Are There Different Kinds of Uveitis?
There are different types of uveitis, depending on which part of the eye is affected.

When the uvea is inflamed near the front of the eye in the iris, it is called iritis. Iritis has a sudden onset and may last six to eight weeks.

If the uvea is inflamed in the middle of the eye, it is called cyclitis. Cyclitis affects the muscle that focuses the lens. Cyclitis can also develop suddenly and can last for several months.

An inflammation in the back of the eye is called choroiditis. Choroiditis is slower to develop and may last longer.

How is Uveitis Treated?
Uveitis is a serious eye condition that may scar the eye. It needs to be treated as soon as possible.

Eye drops, especially corticosteroids and pupil dilators, can reduce inflammation and pain. For more severe inflammation, oral medication or injections may be necessary.

Uveitis can be associated with these complications:

Glaucoma (increased pressure in the eye)
Cataract (clouding of the eye's natural lens)
Neovascularization (growth of new, abnormal blood vessels)
Damage to the retina, including retinal detachment

These complications also may need treatment with eye drops, conventional surgery or laser surgery.

If you have a "red eye" that does not clear up quickly, contact your ophthalmologist.

The above information is from the American Academy of Ophthalmology.

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Diabetic Retinopathy

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?
The four stages of diabetic retinopathy are mild nonproliferative retinopathy moderate nonproliferative retinopathy severe nonproliferative retinopathy proliferative retinopathy.

The first stage is mild nonproliferative retinopathy. At this earliest stage, microaneurysms occur. They are small areas of balloon-like swelling in the retina's tiny blood vessels.
The second stage is moderate nonproliferative retinopathy. As the disease progresses, some blood vessels that nourish the retina are blocked.
The third stage is severe nonproliferative retinopathy. Many more blood vessels are blocked, depriving several areas of the retina of their blood supply. These areas of the retina send signals to the body to grow new blood vessels for nourishment.
The fourth stage is proliferative retinopathy. At this advanced stage, the signals sent by the retina for nourishment trigger the growth of new blood vessels. 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 for diabetic retinopathy. That's why everyone with diabetes should get a comprehensive dilated eye exam at least once a year. Between 40 to 45 percent of Americans diagnosed with diabetes have some stage of diabetic retinopathy. If you have diabetic retinopathy, your doctor can recommend treatment to help prevent its progression.

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 or hemorrhaging occurs. Hemorrhages tend to happen more than once, often during sleep.

Sometimes, the spots clear without treatment, 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 diabetic retinopathy and macular edema detected?
Diabetic retinopathy and macular edema are detected during a comprehensive eye exam that includes a visual acuity test, dilated eye exam, and tonometry.

A visual acuity test is an eye chart test that measures how well you see at various distances.

In a 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.

With tonometry, an instrument measures the pressure inside the eye. Numbing drops may be applied to your eye for this test.

During the dilated eye exam, your eye care professional checks your retina for early signs of the disease. Signs may include leaking blood vessels, retinal swelling, fatty deposits on the retina, damaged nerve tissue, or any changes to the blood vessels.

If your eye care professional believes you need treatment for macular edema, he or she may suggest a fluorescein angiogram.

8. What is 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.

9. How is 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 the retina around the macula that are leaking.

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 care professional if you have vision loss.

10. How is diabetic retinopathy treated?
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 scatter laser treatment. Scatter laser treatment 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, scatter laser treatment can save the rest of your sight. Scatter laser treatment may slightly reduce your color vision and night vision. 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.

11. What happens during laser treatment?
Both focal and scatter laser treatment are performed in your doctor's office or eye clinic. 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.

12. What is a vitrectomy?
If you have a lot of blood in the center of the eye, or 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.

13. What can I expect after a vitrectomy?
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 will also need to use medicated eyedrops to protect against infection.

14. 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 10 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.

15. 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 care professional about low vision services and devices that may help you make the most of your remaining vision. Ask for a referral to a specialist in low vision. Many community organizations and agencies offer information about low vision counseling, training, and other special services for people with visual impairments. A nearby school of medicine or optometry may provide low vision services.

16. What research is being done?
The National Eye Institute, or NEI, is conducting and supporting research that seeks better ways to detect, treat, and prevent vision loss in people with diabetes. This research is conducted through studies in the laboratory and with patients. For example, researchers are studying drugs that may stop the retina from sending signals to the body to grow new blood vessels. Someday, these drugs may help people control their diabetic retinopathy and reduce the need for laser surgery.

17. What can I do to protect my vision?
The National Eye Institute urges everyone with diabetes to have a comprehensive dilated eye exam at least once a year. 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 follow-up care.

18. Does controlling blood sugar slow the onset of diabetic retinopathy?
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.

This tight control of blood sugar control may not be best for everyone, including some elderly patients, children under age 13, or people with heart disease. Be sure to ask your doctor if such a control program is right for you.

Other studies have shown that controlling elevated blood pressure and cholesterol can reduce the risk of vision loss. Controlling these will help your overall health as well as help protect your vision.

19. What are some points to remember about diabetic retinopathy?

If you have diabetes, get a comprehensive dilated eye exam at least once a year.
Proliferative retinopathy can develop without symptoms. If it gets to this advanced stage, you are at high risk for vision loss or even blindness.
Macular edema can develop without symptoms at any of the four stages of diabetic retinopathy.
You can develop both proliferative retinopathy and macular edema and still see fine. However, you are at high risk for vision loss.
Your eye care professional can tell if you have macular edema or any stage of diabetic retinopathy. Whether or not you have symptoms, early detection and timely treatment can prevent vision loss.

20. Where can I get more information?

National Eye Institute
National Institutes of Health

www.nei.nih.gov

Topic last updated: 19 December 2005

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Retinal Artery and Vein Occlusion

What Is It?
The retina is the light-sensitive layer at the back of the eye that is responsible for vision. Blood circulation to most of the retina's surface is through only one artery and only one vein. If either blood vessel or one of their smaller branches is blocked, blood circulation to the retina can be significantly disrupted. The blockage is called an occlusion. When this happens, the eye typically loses vision, often suddenly. The condition is painless.

Retinal Artery Occlusion
The retinal artery carries oxygen-rich blood to the retina. When a blockage occurs in the retina's main artery, or in one of its small branches, the retina's light-sensitive cells gradually begin to suffocate from lack of oxygen. Unless normal circulation to the retina can be restored promptly, these cells will die within a few minutes or hours depending on how completely the blood flow is obstructed. This can cause permanent and often substantial loss of vision.

In adults, there are two main reasons that the retina's artery would become blocked: a thrombus or an embolus.

A thrombus (blood clot) - Inside the retinal artery, a blood clot typically develops at a site where the artery's lining has already been damaged by a chronic illness, such as high blood pressure (hypertension), diabetes or atherosclerosis. Atherosclerosis is a common cardiovascular problem that produces cholesterol deposits called plaques along the walls of arteries, decreasing blood flow.
An embolus (floating blood clot or debris in the bloodstream) - In the retinal artery, an embolus is usually a tiny blood clot or a piece of atherosclerotic plaque that has been carried through the bloodstream from a damaged area of the heart, aorta or carotid artery (in the neck). For this reason, the embolus is often interpreted as a warning sign of cardiovascular disease elsewhere, especially in the carotid artery.

Less often, a retinal artery occlusion may be caused by vasculitis (inflammation of the artery's wall), trauma, blood clots from injections of medication into the eye, sickle cell disease, clotting disorders, oral contraceptives or damage from radiation treatments. Overall, retinal artery occlusion is a rare illness that is responsible for only one out of every 10,000 visits to ophthalmologists (physicians who specialize in eye problems) in the United States. The average person with the illness is between 50 and 70 years old and has a history of heart disease, high blood pressure or diabetes. In almost all cases, only one eye is affected.

Retinal Vein Occlusion
The retinal vein carries blood away from the retina. When the vein is blocked, blood flow backs up and causes tiny hemorrhages, areas of swelling, and other pressure-related damage in portions of the retina that are located near the blocked blood vessels. This can cause minimal or substantial loss of vision, depending on the extent of this retinal damage. Some common risk factors for this form of retinal vessel occlusion include high blood pressure, diabetes, open-angle glaucoma, lymphoma, leukemia, multiple myeloma, syphilis and use of oral contraceptives.

Symptoms
The primary symptom of retinal artery occlusion is a sudden, painless, persistent, substantial loss of vision in one eye. In about 10% of those affected, this loss of vision is preceded by one or more episodes of a condition called amaurosis fugax. Amaurosis fugax is a temporary episode of decreased vision, usually lasting no more than 10 to 15 minutes, that is sometimes described as "closing a curtain" on one eye.

Although retinal vein occlusion also causes painless loss of vision, this vision loss sometimes develops gradually over several days or weeks rather than suddenly. Also, depending on the extent of retinal damage, some people have only minimal blurring of vision, while others have more substantial vision loss.

Diagnosis
After reviewing your symptoms, the doctor will ask questions about your medical history, especially any history of high blood pressure, heart disease, diabetes, glaucoma, eye trauma or amaurosis fugax. Next, your doctor will do a thorough eye examination, including tests of your visual acuity (how well you can see) and peripheral vision. Finally, the doctor will use special eyedrops to dilate (open wide) your pupils to examine the inside of your eye, including the retina. During this examination, the doctor will use an instrument called an ophthalmoscope to see whether your retina's blood supply appears to be normal, or whether there are areas of whiteness (a sign of arterial occlusion), hemorrhage, a visible embolus lodged in a retinal vessel, or other problems. In some cases, the doctor also may order fluorescein angiography, a test that uses an injected dye to analyze blood flow in the eye.

In some people, especially those who are elderly, retinal artery occlusion may be caused by temporal arteritis, a form of blood vessel inflammation, rather than to a thrombus or embolus. A special blood test called an erythrocyte sedimentation rate may help to confirm this diagnosis.

In addition, if the doctor suspects that your eye problem is being caused by emboli from undiagnosed cardiovascular illness, you may need diagnostic tests to evaluate the blood flow in your heart and carotid arteries. Also, blood tests may be necessary to determine your cholesterol levels or to check for blood clotting disorders, especially in very young people.

Expected Duration
Whenever the retina's circulation is blocked, loss of vision may be permanent if the blockage is not removed within 24 hours. Ideally, the problem should be treated within two hours or less.

Prevention
Since many cases of retinal vessel occlusion are related to high blood pressure, atherosclerosis or diabetes, it may be possible to prevent this eye problem by controlling your blood pressure, cholesterol level and blood sugar. Also, all diabetics should have a thorough eye examination through dilated pupils at least once a year.

To help prevent retinal artery occlusion related to traumatic eye injuries, always wear appropriate protective eye gear (goggles, face shield, face mask) at work and while playing sports. Also, remember to use a seat belt whenever you ride in a car to prevent your face and eyes from hitting the dashboard during a collision.

Oral contraceptives have been linked to some cases of retinal vessel occlusion. Ask your doctor about your risk of this rare side effect before you begin taking birth control pills.

Treatment
Treatment depends on the type of occlusion.

Retinal Artery Occlusion
Treatment focuses on increasing blood flow to the retina, while trying to dislodge the thrombus or embolus from the blocked artery. Options include:

Ocular massage - The doctor uses his or her finger to apply pressure to your eye through your closed eyelid.
Breathing carbogen - By breathing this mixture of 95% oxygen and 5% carbon dioxide, you may be able to increase the flow of blood and oxygen to your retina.
Rebreathing carbon dioxide - If carbogen is not available, the doctor may ask you to breathe into a paper bag to increase the amount of carbon dioxide in your blood. The increased level of carbon dioxide should dilate (widen) the arteries in your retina, increasing blood flow.
Anterior chamber paracentesis - An eye specialist uses a needle to remove a few drops of fluid from inside your eye. This decreases the pressure within your eye, making it easier for blood to flow through your retinal artery.
Experimental therapies - These include injection of a clot-dissolving medication directly into the eye's circulation, administration of vasodilators (medications that widen blood vessels), exposure to hyperbaric oxygen and destruction of retinal emboli with lasers.

In rare cases, when retinal artery occlusion is caused by temporal arteritis rather than a thrombus or embolus, treatment involves long-term treatment with high-dose corticosteroid medications.

Retinal Vein Occlusion
Treatment depends on the extent of blockage:

Partial blockage - When only a small branch of the central retinal vein is blocked, sealing the damaged area with a laser (laser photocoagulation) may improve vision.
Total blockage - When the entire central retinal vein is blocked, there is no effective treatment. However, laser photocoagulation may be used to prevent complications, such as glaucoma.

When To Call A Professional
If you experience a sudden loss of vision, seek emergency medical help immediately. Prompt treatment provides the best chance at restoring vision, particularly when the retina's artery is blocked.

Prognosis
If the entire retinal artery has been blocked, the outlook for restoring vision is usually poor, especially if symptoms have lasted longer than a few hours. If only a small branch of the artery is blocked, however, the prognosis is often very good; about 80% of affected eyes eventually improve.

The situation is similar for retinal vein occlusions. Blockage of the entire vein has a much poorer prognosis than blockage of only one small branch. Laser treatments sometimes produce dramatic improvements in vision in people with small branch occlusions.

Additional Info

National Eye Institute (NEI)

http://www.nei.nih.gov

American Academy of Ophthalmology

http://www.aao.org/news/eyenet/

Above information from Aetna, InteliHealth

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Central Retinal Artery and Vein Occlusions

The central retinal artery, the main vessel that supplies blood to the retina, can become completely blocked because of atherosclerosis or particles, such as blood clots, that float in the bloodstream and block a vessel (emboli). Inflammation of the blood vessels is also a possible cause of retinal artery blockage. In people with glaucoma, diabetes, or high blood pressure, various processes may occur, which can lead to blockage of the veins.

If the central retinal artery is blocked, the affected eye has a sudden but painless loss of vision. Blockage of the central retinal vein causes engorged veins and swelling of the front of the optic nerve. Vision loss ranges from mild to severe as in central retinal artery blockage. Recurrences are common.

In addition to severe vision loss, complications of blockage of the central retinal artery or vein include hemorrhage into the eye and glaucoma caused by growth of abnormal blood vessels on the iris and angle, where fluid drains from the eye.

Diagnosis and Treatment
Using an ophthalmoscope, a doctor can see changes in blood vessels and other indications of decreased blood supply to the retina, such as paleness of the retina in the case of arterial blockage or engorged veins and swelling of the front of the optic nerve in the case of venous blockage. Fluorescein angiography-a procedure in which a doctor injects dye into a vein and then photographs the retina-helps determine the extent of damage to the retina and helps the doctor plan treatment. Doppler ultrasound scanning may sometimes be used to observe blood flow in the vessels.

Immediate treatment is often given in an attempt to unblock the retinal artery. However, treatments are rarely effective. Pressure inside the eye can be lowered by intermittently massaging the closed eyelids with the fingers. Alternatively, a procedure called anterior chamber paracentesis may help lower pressure inside the eye. In this procedure, drops are placed in the eye to numb the eye, and then a needle is inserted into the anterior chamber of the eye to withdraw a small amount of fluid, thereby rapidly lowering the pressure in the eye. Lowering the pressure inside the eye by massage or by anterior chamber paracentesis may dislodge a blood clot or other embolus and allow it to enter a smaller branch of the vessel, thereby reducing the area of damage to the retina. There is no generally accepted drug therapy. Laser treatment may be used to destroy abnormal blood vessels if they develop on the iris or angle.

Above information from Merck Manuals

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Retinopathy of Prematurity

The information provided in this Resource Guide was developed by the National Eye Institute to help patients and their families search for general information about early treatment for retinopathy of prematurity study (ETROP). An eye care professional who has examined the patient's eyes and is familiar with his or her medical history is the best person to answer specific questions.

Other Names
retrolental fibroplasia

What is retinopathy of prematurity?
Retinopathy of prematurity (ROP) is a potentially blinding eye disorder that primarily affects premature infants weighing about 23 pounds (1250 grams) or less that are born before 31 weeks of gestation (A full-term pregnancy has a gestation of 3842 weeks). The smaller a baby is at birth, the more likely that baby is to develop ROP. This disorder-which usually develops in both eyes-is one of the most common causes of visual loss in childhood and can lead to lifelong vision impairment and blindness. ROP was first diagnosed in 1942.

How many infants have ROP?
Today, with advances in neonatal care, smaller and more premature infants are being saved. These infants are at a much higher risk for ROP. Not all babies who are premature develop ROP. There are approximately 3.9 million infants born in the U.S. each year; of those, about 28,000 weigh 23 pounds or less. About 14,00016,000 of these infants are affected by some degree of ROP. The disease improves and leaves no permanent damage in milder cases of ROP. About 90 percent of all infants with ROP are in the milder category and do not need treatment. However, infants with more severe disease can develop impaired vision or even blindness. About 1,1001,500 infants annually develop ROP that is severe enough to require medical treatment. About 400600 infants each year in the US become legally blind from ROP.

What causes ROP?
ROP occurs when abnormal blood vessels grow and spread throughout the retina, the tissue that lines the back of the eye. These abnormal blood vessels are fragile and can leak, scarring the retina and pulling it out of position. This causes a retinal detachment. Retinal detachment is the main cause of visual impairment and blindness in ROP.

Several complex factors may be responsible for the development of ROP. The eye starts to develop at about 16 weeks of pregnancy, when the blood vessels of the retina begin to form at the optic nerve in the back of the eye. The blood vessels grow gradually toward the edges of the developing retina, supplying oxygen and nutrients. During the last 12 weeks of a pregnancy, the eye develops rapidly. When a baby is born full-term, the retinal blood vessel growth is mostly complete (The retina usually finishes growing a few weeks to a month after birth). But if a baby is born prematurely, before these blood vessels have reached the edges of the retina, normal vessel growth may stop. The edges of the retina-the periphery-may not get enough oxygen and nutrients.

Scientists believe that the periphery of the retina then sends out signals to other areas of the retina for nourishment. As a result, new abnormal vessels begin to grow. These new blood vessels are fragile and weak and can bleed, leading to retinal scarring. When these scars shrink, they pull on the retina, causing it to detach from the back of the eye.

Are there different stages of ROP?
Yes. ROP is classified in five stages, ranging from mild (stage I) to severe (stage V):

Stage I - Mildly abnormal blood vessel growth. Many children who develop stage I improve with no treatment and eventually develop normal vision. The disease resolves on its own without further progression.
Stage II - Moderately abnormal blood vessel growth. Many children who develop stage II improve with no treatment and eventually develop normal vision. The disease resolves on its own without further progression.
Stage III - Severely abnormal blood vessel growth. The abnormal blood vessels grow toward the center of the eye instead of following their normal growth pattern along the surface of the retina. Some infants who develop stage III improve with no treatment and eventually develop normal vision. However, when infants have a certain degree of Stage III and "plus disease" develops, treatment is considered. "Plus disease" means that the blood vessels of the retina have become enlarged and twisted, indicating a worsening of the disease. Treatment at this point has a good chance of preventing retinal detachment.
Stage IV - Partially detached retina. Traction from the scar produced by bleeding, abnormal vessels pulls the retina away from the wall of the eye.
Stage V - Completely detached retina and the end stage of the disease. If the eye is left alone at this stage, the baby can have severe visual impairment and even blindness.

Most babies who develop ROP have stages I or II. However, in a small number of babies, ROP worsens, sometimes very rapidly. Untreated ROP threatens to destroy vision.

How is ROP treated?
The most effective proven treatments for ROP are laser therapy or cryotherapy. Laser therapy "burns away" the periphery of the retina, which has no normal blood vessels. With cryotherapy, physicians use an instrument that generates freezing temperatures to briefly touch spots on the surface of the eye that overlie the periphery of the retina. Both laser treatment and cryotherapy destroy the peripheral areas of the retina, slowing or reversing the abnormal growth of blood vessels. Unfortunately, the treatments also destroy some side vision. This is done to save the most important part of our sight-the sharp, central vision we need for "straight ahead" activities such as reading, sewing, and driving

Both laser treatments and cryotherapy are performed only on infants with advanced ROP, particularly stage III with "plus disease." Both treatments are considered invasive surgeries on the eye, and doctors don't know the long-term side effects of each.

In the later stages of ROP, other treatment options include:

Scleral buckle. This involves placing a silicone band around the eye and tightening it. This keeps the vitreous gel from pulling on the scar tissue and allows the retina to flatten back down onto the wall of the eye. Infants who have had a sclera buckle need to have the band removed months or years later, since the eye continues to grow; otherwise they will become nearsighted. Sclera buckles are usually performed on infants with stage IV or V.
Vitrectomy. Vitrectomy involves removing the vitreous and replacing it with a saline solution. After the vitreous has been removed, the scar tissue on the retina can be peeled back or cut away, allowing the retina to relax and lay back down against the eye wall. Vitrectomy is performed only at stage V.

What happens if treatment does not work?
While ROP treatment decreases the chances for vision loss, it does not always prevent it. Not all babies respond to ROP treatment, and the disease may get worse. If treatment for ROP does not work, a retinal detachment may develop. Often, only part of the retina detaches (stage IV). When this happens, no further treatments may be needed, since a partial detachment may remain the same or go away without treatment. However, in some instances, physicians may recommend treatment to try to prevent further advancement of the retinal detachment (stage V). If the center of the retina or the entire retina detaches, central vision is threatened, and surgery may be recommended to reattach the retina.

Are there other risk factors for ROP?
In addition to birth weight and how early a baby is born, other factors contributing to the risk of ROP include anemia, blood transfusions, respiratory distress, breathing difficulties, and the overall health of the infant.

An ROP epidemic occurred in the 1940s and early 1950s when hospital nurseries began using excessively high levels of oxygen in incubators to save the lives of premature infants. During this time, ROP was the leading cause of blindness in children in the US. In 1954, scientists funded by the National Institutes of Health determined that the relatively high levels of oxygen routinely given to premature infants at that time were an important risk factor, and that reducing the level of oxygen given to premature babies reduced the incidence of ROP. With newer technology and methods to monitor the oxygen levels of infants, oxygen use as a risk factor has diminished in importance.

Although it had been suggested as a factor in the development of ROP, researchers supported by the National Eye Institute determined that lighting levels in hospital nurseries has no effect on the development of ROP.

Can ROP cause other complications?
Yes. Infants with ROP are considered to be at higher risk for developing certain eye problems later in life, such as retinal detachment, myopia (nearsightedness), strabismus (crossed eyes), amblyopia (lazy eye), and glaucoma. In many cases, these eye problems can be treated or controlled.

NEI-Supported Research
The NEI-supported clinical studies on ROP include:

The Cryotherapy for Retinopathy of Prematurity (CRYO-ROP)-Outcome Study of Cryotherapy for Retinopathy of Prematurity Study examined the safety and effectiveness of cryotherapy (freezing treatment) of the peripheral retina in reducing the risk of blindness in certain low birth-weight infants with ROP. Follow-up results confirm that applying a freezing treatment to the eyes of premature babies with ROP helps save their sight. The follow-up results also give researchers more information about how well the babies can see in the years after cryotherapy.
The Effects of Light Reduction on Retinopathy of Prematurity (Light-ROP) Study evaluated the effect of ambient light reduction on the incidence of ROP. The study determined that light reduction has no effect on the development of a potentially blinding eye disorder in low birthweight infants. The study determined that light reduction in hospital nurseries has no effect on the development of ROP.

Other Resources
The following organizations may be able to provide additional information on retinopathy of prematurity:

American Association for Pediatric Ophthalmology and Strabismus

http://www.aapos.org

Association for Retinopathy of Prematurity and Related Diseases (ROPARD)

http://www.ropard.org

National Eye Institute (NEI)

http://www.nei.nih.gov

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Vitreous Detachment

Most of the eye's interior is filled with vitreous, a gel-like substance that helps the eye maintain a round shape. There are millions of fine fibers intertwined within the vitreous that are attached to the surface of the retina, the eye's light-sensitive tissue. As we age, the vitreous slowly shrinks, and these fine fibers pull on the retinal surface. Usually the fibers break, allowing the vitreous to separate and shrink from the retina. This is a vitreous detachment. In most cases, a vitreous detachment is not sight-threatening and requires no treatment.

As the vitreous shrinks, it becomes somewhat stringy, and the strands can cast tiny shadows on the retina that you may notice as floaters, which appear as little "cobwebs" or specks that seem to float about in your field of vision. If you try to look at these shadows they appear to quickly dart out of the way. One symptom of a vitreous detachment is a small but sudden increase in the number of new floaters. This increase in floaters may be accompanied by flashes of light (lightning streaks) in your peripheral, or side, vision. In most cases, either you will not notice a vitreous detachment, or you will find it merely annoying because of the increase in floaters.

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

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 create a macular hole or lead to a retinal detachment. Both of these conditions are sight-threatening and should be treated immediately. If left untreated, a macular hole or detached retina can lead to permanent vision loss in the affected eye. Those who experience a sudden increase in floaters or an increase in flashes of light in peripheral vision 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 macular hole or detached retina, early treatment can help prevent loss of vision.

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Retinal Disorders

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