These individuals are considered visually impaired. Visual impairment may be caused by a number of eye diseases, including age-related macular degeneration, diabetic retinopathy, glaucoma and cataracts. Visual impairment may also be caused by trauma or inherited eye disorders.

Although many eye diseases can be treated by your ophthalmologist (Eye M.D.), some may result in the unavoidable loss of central vision (used for reading/detail work) or peripheral (side) vision—or both.

Visual impairment can range from mild to severe. Federal regulations define a certain level of visual impairment as legal blindness, which should not be confused with total blindness. Most of the approximately one million Americans defined as legally blind keep some useful vision.

HOW IS SIGHT MEASURED?

To understand the definition of visual impairment and legal blindness, you need to know how your eyesight is measured. Central vision is measured using an eye chart. The results are recorded as a pair of numbers called visual acuity. Normal sight is scored as 20/20. The first number is the distance from the eye chart. The second number is the distance from which a normal eye sees a letter on the chart clearly. Someone with a visual acuity of 20/20 can see certain sized letters at a distance of 20 feet. Someone with a visual acuity of 20/60 only sees letters at 20 feet that a normal eye identifies at 60 feet. The higher the second number of your visual acuity, the worse your vision will be.

Peripheral (side) vision is measured with an instrument called a perimeter. Using targets of different sizes and brightness, a perimeter measures the total area that you can see while looking straight ahead. The results are recorded in degrees. In a normal eye, peripheral vision is 180 degrees. A person with a much narrower range of side vision may have trouble walking, recognizing people in a large room or driving a car—even when his or her central vision is excellent.

Your ophthalmologist may also administer other tests to measure your level of visual function. These include tests of eye movement, color and contrast vision, three-dimensional vision, and adjustment to light and dark.

WHAT IS LEGAL BLINDNESS?

When your visual acuity with eyeglasses or corrective lenses is 20/200 or worse, or your side vision is 20 degrees or less, you are considered legally blind—even though you may still have some useful vision. You may qualify for certain government benefits or receive assistance from public and private organizations if you are legally blind.

WHAT IS VISUAL IMPAIRMENT?

If your vision with eyeglasses or corrective lenses is 20/60 or worse, you are considered visually impaired. Limitation of side vision, abnormal color vision, or presence of double vision in one eye may also determine visual impairment.

WHAT IS A VISUAL DISABILITY?

If you cannot perform certain tasks because of your visual impairment, you are considered “visually disabled.” An exact rating or quantification of the disability is necessary to receive worker’s compensation, insurance disability benefits, legal claims, or certain forms of government assistance.

Visual disability is expressed in percentages to determine how much the whole person is disabled by his or her visual handicap. For example, total loss of vision in both eyes is a 100% disability of vision, but only an 85% disability of the whole person.

WHAT CAN I DO ABOUT MY VISUAL IMPAIRMENT?

• Schedule regular eye examinations with your ophthalmologist to monitor your eye health and your remaining vision. Your eyes can be affected by more than one condition, so it is important that any new problems be diagnosed and treated promptly in order to preserve your remaining vision.
• Ask your ophthalmologist about low-vision resources. There are many rehabilitation services and devices for people with reduced vision, including counselors, large and high contrast print materials, audio publications and materials, optical and electronic magnifiers, mobility training, and improved lighting devices.
• Join a support group for people with similar eye problems.
• Ask your ophthalmologist to refer you to the appropriate state and local agencies for the visually impaired. These agencies can help you obtain handicapped parking, low-vision services, Social Security and Department of Veterans Affairs benefits, or information about federal and state tax exemptions for the visually impaired.

This test produces a map of your complete field of vision. Visual field tests help your ophthalmologist (Eye M.D.) monitor any loss of vision and diagnose eye problems and disease.

HOW IS A VISUAL FIELD TEST PERFORMED?

The test is performed with a large, bowl-shaped instrument called a perimeter. In order to test one eye at a time, one of your eyes is temporarily patched during the test. You will be seated and positioned comfortably in front of the perimeter and asked to look straight ahead at a fixed spot (the fixation target). The computer randomly flashes points of light around the bowl-shaped perimeter. When you see a light, press the indicator button. It is very important to always keep looking straight ahead. Do not move your eyes to look for the target; wait until it appears in your side vision. A delay in seeing a light does not necessarily mean your field of vision is damaged.

If you need to rest during the test, tell the technician and he or she will pause the test until you are ready to continue.

Your ophthalmologist will interpret the results of your test and discuss them with you.

TYPES OF VISUAL FIELD TESTS

There are two main testing methods:

Moving Targets. Lighted targets are moved from where you can’t see them (beyond your side vision) in towards the center of your vision until you do see them. As soon as the target appears in your field of vision, you press the indicator button.

Fixed Targets. Instead of targets moving into your field of vision, fixed targets suddenly appear in different areas on the screen. When the targets appear, you press the indicator button.

WHY ARE VISUAL FIELD TESTS IMPORTANT?

Initially, visual field tests help your ophthalmologist diagnose problems with your eyes, optic nerve or brain, including:

• loss of vision;
• glaucoma;
• disorders of your retina (layer of cells that lines the back of your eye);
• other neurologic conditions including brain tumors, multiple sclerosis and increased intracranial pressure.

Visual field testing is used to measure peripheral vision loss. The test is repeated at appropriate time intervals to determine if vision loss is progressing or remaining stable. If you are diagnosed with a particular disorder or disease, such as glaucoma, visual field tests become a routine part of your treatment.

If you have any questions about visual field testing or your vision, be sure to talk with your ophthalmologist.

Patching is one technique for treating amblyopia. A patch is placed over the better-seeing eye to make the child use and develop good vision in the “lazy eye.”

Using eyedrops is another technique for treating amblyopia. One drop of the medication Atropine is placed in the better-seeing eye daily. This medication blurs vision in the better eye, making the child use and develop good vision in the “lazy eye.” Your ophthalmologist (Eye M.D.) should instruct you on the proper use of Atropine.

WHEN SHOULD TREATMENT BEGIN?

Treatment of amblyopia should begin as early as possible. If your child is old enough to understand, explain the reason for using the patch or eyedrops. It may be helpful to demonstrate patching on a doll.

If your child attends school or preschool, explain the amblyopia treatment to the teacher. Enlist the teacher’s help to encourage your child to perform his or her usual tasks, while also making allowances for added difficulty from the treatment. The teacher can also help explain your child’s situation to classmates.

HOW LONG WILL THE TREATMENT TAKE?

Treatment time will vary for different children. As a general rule, the younger the child is and less amount of time the eye has been “lazy,” the shorter the length of treatment will be. In young children, vision may improve rapidly.

To ensure that a child is given the best possible chance to develop normal vision, the patching or eyedrops may be continued for a few weeks or months after vision stabilizes.

Once vision has improved in the “lazy eye,” there is a small chance that it can become worse again. Close observation of the eye is necessary throughout childhood.

If vision does not improve after a reasonable period, your ophthalmologist may recommend discontinuing treatment.

ARE THERE ANY SIDE EFFECTS FROM TREATMENT?

Because the better-seeing eye is not used during treatment, occasionally vision in that eye may decrease, but it will usually return to normal as soon as that eye is used again.

The skin at and around a patched eye may become irritated. Trying a different type of patch or changing the shape of the patch may help relieve skin irritation. To prevent irritation, leave the patch off at night while the child is sleeping.

There is also an increased risk of accidents while the child is wearing a patch. To prevent accidents, the child should be monitored closely while wearing a patch and not engage in hazardous activities such as bicycling, climbing gym sets, etc.

WILL EXERCISE HELP?

No; the best exercise is wearing the patch or using the eye drops as instructed by your ophthalmologist. Fine, detailed work that holds the child’s interest will also encourage the use of the “lazy eye” and help speed visual recovery.

WILL THE TREATMENT CORRECT MISALIGNED EYES?

No; patching or eyedrops improves vision in an amblyopic (“lazy”) eye, but does not help misaligned eyes. Once vision is good in each eye, your ophthalmologist can recommend treatment for realigning the eyes.

WHAT KIND OF PATCH SHOULD BE USED?

The patch should be comfortable, remain firmly in place, and not allow the child to “peek” around the edges. Commercial patches are available at most drug stores and come in regular and “junior” sizes. The patch should be attached directly to the skin around the eye for best results. A gauze pad held firmly in place with hypoallergenic tape, or a dark cloth cut in an oval shape, can also serve as an adequate homemade patch.

Black eye patches that are held on the child’s head with elastic or ties, such as a pirate-type patch, should not be used; they are too easy to remove or peek around.

Patches that slip over eyeglasses are also available and can be an alternative for children already accustomed to patching. However, since these patches can slip and allow “peeking,” they are not a good choice for children who are just beginning treatment.

WHAT IF THE CHILD REMOVES THE PATCH?

For infants and toddlers, try applying extra tape over the patch to secure it. Thin, cellophane-type tape may make it more difficult to remove the patch. If your child is still able to remove the patch, try covering his or her hands with mittens or socks. Distraction is often helpful for younger children. Also, using a reward system is a very effective strategy to encourage the child to wear the patch.

When you first start treatment, it may be very difficult for both you and your child. With time, and with the advice and support of your ophthalmologist, the treatment will be successful.

In a small number of people, the thyroid gland malfunctions and produces more hormones than the body needs. This is called hyperthyroidism, or Graves’ disease.

The overproduction of thyroid hormones in Graves’ disease can cause various eye and vision problems.

HOW DOES GRAVES’ DISEASE AFFECT THE EYES?

Graves’ disease can affect your eyes in many different ways. The symptoms may vary from person to person and may fluctuate or clear up suddenly without any treatment. Following are several common eye problems associated with the disease:

Eye protrusion. The excess hormones in Graves’ disease cause the muscles in and around the eye to swell and push the eye forward. This eye bulge is a characteristic symptom of Graves’ disease and causes patients to look as if they are constantly staring.

Eyelid retraction. The combination of eyelid swelling and eye protrusion may cause the eyelids to retract and reveal the white parts of the eye above and below the iris.

Dry eye. Due to eye protrusion and eyelid retraction, your eyes are more exposed to environmental elements, such as wind and dust, and may become very dry. Dry eye can cause several side effects including:

• irritation and discomfort of the eye;
• inflammation of the eye;
• excessive tearing;
• light sensitivity;
• blurred vision;
• ulcers on the cornea (the clear front window of the eye);
• scarring of the cornea.

If untreated, severe dry eye can lead to vision loss.

Double vision. Muscle swelling may cause double vision. It may occur constantly or only when looking in certain directions. Prolonged and excessive muscle swelling can also compress and damage the optic nerve (the nerve in the eye that sends visual impulses to the brain) and cause blindness.

Eye “bags.” Eyelid swelling can also cause fatty tissue around the eyes to bulge forward. This causes the appearance of “bags” around the eyes and can make patients look prematurely aged.

HOW ARE EYE AND VISION PROBLEMS TREATED?

Your ophthalmologist (Eye M.D.) will monitor eye protrusion and eyelid retraction by taking precise measurements of your eyes. If the measurements are increasing, or if your symptoms are getting worse, treatment may be needed.

A combination of non-surgical and surgical methods may be used to treat your symptoms. Non-surgical treatment options may include:

• applying lubricating ointment and/or artificial tears to relieve some symptoms of dry eye;
• elevating your head at night to reduce muscle swelling;
• taking steroid medications by mouth to control the eye muscle swelling and inflammation;
• wearing sunglasses to relieve light sensitivity;
• applying cool compresses to the eyes to relieve the discomfort associated with eye irritation and inflammation;
• using eyeglasses with prisms to reduce double vision.

Surgical treatment options may include:

• repositioning the eye and/or the eye muscles to relieve double vision and improve cosmetic appearance;
• repositioning eyelid muscles to correct eyelid retraction, relieve the effects of dry eye, and improve cosmetic appearance;
• removing scarred tissue from the muscles of the eye or eyelid;
• relieving compression on the optic nerve to preserve sight.

Eye disorders caused by thyroid disease can usually be managed very successfully.

There are two carotid arteries: one on the right side of the neck (which supplies blood to the right side of the brain) and one on the left side of the neck (which supplies blood to the left side of the brain).

When blood flowing through the carotid artery is reduced or blocked, the eyes and brain do not receive enough oxygen. As a result, brain function and vision can be greatly affected.

WHAT HAPPENS WHEN THE CAROTID ARTERY IS BLOCKED?

A narrowing, hardening or irregularity of the carotid artery can cause a blood clot or accumulation of debris to form in the artery. This is known as carotid artery disease. The debris may break off into the blood stream and interfere with blood flow to the eyes and brain. A reduction of blood flow through one of the carotid arteries may cause temporary vision loss in the eye on the same side. The loss of vision is like a curtain being drawn over the eye and usually lasts just one or two minutes. Weakness or numbness can also occur on one side of the body. Temporary blockages of the arteries are called transient ischemic attacks (TIA). You should see your ophthalmologist (Eye M.D.) or physician immediately if you experience such episodes. TIAs are warning signs that a complete blockage of the artery may occur.

A complete blockage of the carotid artery can cause a stroke. The effects of stroke can be either mild (loss of side vision or slight muscle weakness) or severe (complete loss of vision, paralysis of one side of the body, loss of speech).

CAN A BLOCKED CAROTID ARTERY BE PREVENTED?

Several factors increase the risk of developing carotid artery disease, including:

• smoking;
• high cholesterol;
• high alcohol consumption;
• obesity;
• high blood pressure;
• lack of exercise;
• family history.

A healthy lifestyle that includes a good diet, normal body weight, exercise and low cholesterol level will greatly reduce your chances of blocked arteries and stroke. If you have a family history of carotid artery disease or are at risk for stroke, examinations by your physician, a radiologist and/or ophthalmologist can help detect dysfunction in the carotid arteries. Examinations may include:

• Ultrasound, to hear and measure blood flow through the arteries;
• magnetic resonance angiogram (MRA), which produces electronic images of the arteries;
• computerized tomography angiogram (CTA), which involves injecting a special dye into the bloodstream to illuminate the arteries;
• dilation (widening) of the pupil with eyedrops to examine the eye for blocked blood vessels.

HOW IS CAROTID ARTERY DISEASE TREATED?

Treatment of carotid artery disease may involve one or more of the following:

• blood-thinning medications, such as aspirin, to help prevent blood clots;
• medication to lower blood pressure;
• surgery to remove the blocked section of the artery.

In many cases, your ophthalmologist and other medical doctors will work together to coordinate the treatment of carotid artery disease.

HOW DO TEARS DRAIN FROM THE EYE?

As new tears are produced, old tears drain from the eye through two small openings called the upper and lower puncta, which are located at the inside corner of the upper and lower eyelids near the nose. The tears then move through a passage called the canaliculus and into the lacrimal sac. From the sac, the tears then drop down the tear duct, called the nasolacrimal duct, and drain into the back of the nose and throat. That is why your nose runs when you cry.

EXCESSIVE TEARING MAY OCCUR FROM THE FOLLOWING:

• injury, birth defects, infection or other blockage of the lacrimal (tear) drainage system;
• eyelid or eyelash disorders;
• infection in the eye;
• wind, smoke, fumes or other environmental irritants;
• glaucoma;
• certain medications;
• allergic reaction;
• eyestrain;
• dry eyes;
• foreign material in the eye;
• scratch on the eye.

HOW IS THE CAUSE OF EXCESSIVE TEARING DETERMINED?

A thorough eye examination by an ophthalmologist (Eye M.D.) is necessary to determine the cause of excessive tearing. He or she may also:

• irrigate your tear drainage system with fluid to make sure the pathway is open;
• measure tear production;
• measure eye pressure;
• illuminate the tear drain with a fluorescent dye test;
• perform computerized tomography (CT) scanning.

HOW IS EXCESSIVE TEARING TREATED?

Once your ophthalmologist determines the cause, treatment may include one or more of the following:

• surgical opening of the blocked drainage system;
• surgery to repair an injured drainage system;
• removal of an inturned eyelash or foreign body in the eye;
• adding a new opening from the lacrimal sac into the nose, a procedure known as dacryocystorhinostomy (DCR);
• use of lubricating eyedrops or ointment;
• insertion of an artificial tear duct implant.

Your ophthalmologist will discuss the most appropriate form of treatment with you.

It usually appears as a single, concentrated spot of red, or many diffuse red splotches, on the white of the eye. The red represents blood under the conjunctiva, the clear membrane that covers the white of the eye (called the sclera) and the inner eyelids.

The conjunctiva contains numerous blood vessels and capillaries, the tiniest blood vessels in the body. These vessels can break, causing blood to leak between the conjunctiva and the sclera. This minor bleeding under the eye’s outer membrane is what causes the bright red spot to appear on the white of the eye.

Seeing a subconjunctival hemorrhage on your eye can be alarming. Yet it is actually a common occurrence, and it is almost always harmless, minor, and will heal on its own. It does not affect vision and generally does not cause pain either. There are usually no sensations or symptoms, other than the appearance of the red spot. In fact, a person may not even be aware that he or she has a subconjunctival hemorrhage until someone points it out, or the person looks in the mirror.

WHAT CAUSES SUBCONJUNCTIVAL HEMORRHAGE?

The most common causes are coughing, sneezing, straining, or any similar action that temporarily raises blood pressure in the veins, leading to a small rupture in a blood vessel or capillary. Subconjunctival hemorrhage can also occur because of trauma to the eye, even minor trauma such as rubbing the eye vigorously.

Other common but less frequent causes of subconjunctival hemorrhage include diabetes mellitus, high blood pressure, and excessive amounts of certain medications such as aspirin or blood thinners (like coumadin), which affect the body’s bleeding mechanisms.

Much less frequent to rare causes may include blood clotting disorders or other systemic blood disorders. If you have recurrent or excessive subconjunctival hemorrhages, your ophthalmologist (Eye M.D.) will perform a medical work-up, assess your risk factors, and order appropriate laboratory studies, sometimes in collaboration with your primary care physician.

HOW IS SUBCONJUNCTIVAL HEMORRHAGE TREATED?

Treatment is generally not necessary. Over time, the blood spot will slowly disappear, clearing up on its own. This may take days or weeks, depending on the size of the blood spot. If your eye is irritated, your ophthalmologist may recommend that you use over-the-counter artificial tears. In general, expect your ophthalmologist to reassure you that the blood spot will go away. Although subconjunctival hemorrhage can seem alarming, it is usually a temporary, harmless condition that your ophthalmologist can assess appropriately for you.

In ROP, abnormal blood vessels grow on the retina—the light-sensitive layer of cells on the back of the eye that allow us to see.

In some cases, the abnormal blood vessels may shrink and go away without treatment. In other cases, the vessels may continue to develop and serious eye and vision problems may occur such as:

• myopia (nearsightedness);
• detachment of the retina;
• amblyopia (lazy eye);
• strabismus (misaligned eyes);
• glaucoma (increased eye pressure);
• vision loss or blindness.

WHAT CAUSES ROP?

Doctors do not know for certain what causes ROP. Blood vessels in the eye normally finish developing in the last few weeks before birth. Premature infants, however, leave the protective uterus before blood vessels of the eye have had a chance to fully develop. The infants are then exposed to elements such as medication, high levels of oxygen, light and temperature changes. These factors may interfere with the normal development of blood vessels in the eye and cause ROP.

Other factors that may have an effect on ROP development include:

• low birth weight;
• low gestational age (a 12-week premature baby has a greater risk of developing ROP than an eight-week premature baby);
• use of supplemental oxygen after birth;
• vitamin E deficiency;
• race (Caucasians are more at risk than African- Americans);
• anemia;
• respiratory complications.

HOW IS ROP DETECTED?

Premature babies should be screened for ROP and all other at-risk illnesses shortly following birth. An ophthalmologist (Eye M.D.) can diagnose ROP during an examination of the baby’s eyes in a hospital’s neonatal intensive care unit (NICU) or nursery.

ROP may not be apparent, however, until several weeks after birth. Therefore, premature babies at risk for ROP should also have their eyes examined by an ophthalmologist 4–6 weeks following birth. If ROP is diagnosed, the examinations should continue regularly until the abnormal blood vessel growth goes away on its own or is adequately treated by the ophthalmologist.

HOW IS ROP TREATED?

Early stages of ROP do not require any treatment. If ROP advances, laser treatment is most often used to eliminate the abnormal blood vessels. Another method of treatment is cryotherapy. This procedure uses a special instrument to freeze and destroy the abnormal blood vessels.

Treatment for vision problems may include one or more of the following:

• eyeglasses;
• eyedrops;
• temporarily patching one eye (to treat amblyopia);
• eye surgery.

All premature children and children with ROP need to be followed closely for vision problems.

The retina is the layer of light-sensing cells lining the back of your eye that converts light rays into impulses. The impulses are sent through the optic nerve to your brain, where they are recognized as images.

WHAT ARE THE SYMPTOMS OF RETINITIS PIGMENTOSA?

Retinitis pigmentosa causes slow loss of vision. Symptoms begin with decreased night vision and later progress to loss of peripheral (side) vision. Some people may also have difficulty identifying colors. The rate of vision change varies in different people depending on the genetic makeup of their disorder.

As night vision decreases, the ability to adjust to darkness becomes slower and slower. You may:

• stumble over objects in the dark;
• find driving at dusk and night difficult;
• see poorly in dimly lit rooms, such as a movie theater.

While your vision during the day may be completely normal, your inability to see in dark conditions is considered “night blindness.”

Loss of side vision also makes moving around more difficult, causing noticeable clumsiness from not being able to see objects below and around you. As the outer areas of vision slowly disappear, the condition commonly referred to as “tunnel vision” occurs. Many people retain a wide enough scope of useful vision for a long period of time. In some cases, central vision may be affected first, making detail work difficult, such as reading or threading a needle. This is referred to as macular dystrophy, because the central area of the retina, called the macula, is affected.

WHAT CAUSES RETINITIS PIGMENTOSA?

Retinitis pigmentosa is thought to be caused by defects of certain genes in the body. The defects cause cells in the retina to malfunction and begin to break down. Retinitis pigmentosa is often hereditary (runs in families). If you, or your partner, have retinitis pigmentosa, there may be up to a 50 percent chance that you will pass it along to your children. Ask your ophthalmologist (Eye M.D.) about genetic counseling if you are planning to have children.

IS THERE ANY TREATMENT FOR RETINITIS PIGMENTOSA?

Research has shown that Vitamin A can slow the progression of retinitis pigmentosa. Your ophthalmologist can advise you about the risks and benefits of Vitamin A and how much you can take safely.

Research is currently directed toward finding the hereditary cause of many types of retinitis pigmentosa. As hereditary defects are discovered, it may be possible to develop treatments to prevent the progression of retinitis pigmentosa.

Special low-vision aids and services can help people with poor vision continue doing many activities of daily life. Ask your ophthalmologist or contact the following organizations for more information and resources near you:

AMERICAN FOUNDATION FOR THE BLIND
11 Penn Plaza, Suite 300
New York, NY 10001
1.800.232.5463
www.afb.org

NATIONAL ASSOCIATION FOR VISUALLY HANDICAPPED
NAVH New York City
22 West 21st Street, 6th Floor
New York, NY 10010
212.889.3141
www.navh.org

NAVH San Francisco
507 Polk Street, Suite 420
San Francisco, CA 94102
415.775.6284
www.navh.org

The retina is the layer of light-sensing cells lining the back of your eye. It converts light rays into signals, which are sent through the optic nerve to your brain where they are recognized as images.

A blocked vein damages the blood vessels of the retina. Hemorrhages (bleeding) and leakage of fluid occurs from the areas of blocked blood vessels.

There are two different types of retinal vein occlusion:

Central retinal vein occlusion (CRVO): when the main vein of the eye (located at the optic nerve) becomes blocked

Branch retinal vein occlusion (BRVO): when one of the smaller branches of vessels attached to the main vein becomes blocked.

WHO IS AT RISK FOR A RETINAL VEIN OCCLUSION?

Certain illnesses increase your risk for developing retinal vein occlusion, including:

• diabetes;
• glaucoma;
• high blood pressure;
• age-related vascular (blood vessel) disease;
• blood disorders.

If a branch retinal vein occlusion occurs in one eye, there is an increased chance (about 10%) that a branch or central vein occlusion will occur in the other eye in the future.

WHAT ARE THE COMPLICATIONS AND SYMPTOMS OF RETINAL VEIN OCCLUSION?

Macular edema. If blood and fluid leak into the central part of the retina called the macula, swelling of the macula occurs (called macular edema). The macula is the part of your retina responsible for your fine detail vision. It is what allows you to read small print, thread a needle, and read street signs. Macular edema causes blurred and/or decreased vision.

Abnormal blood vessel growth (neovascularization). Retinal vein occlusion can cause abnormal vessels to begin to grow in the retina. These new vessels are very fragile and may bleed or leak fluid into the vitreous—the gel-like substance that fills the center of the eye. Small spots or clouds in your field of vision called floaters can appear. In more advanced cases of neovascularization, the abnormal blood vessels may actually cause the retina to detach from the back of the eye.

Pain in the eye. In severe cases of CRVO, a blocked vein causes abnormal blood vessel growth, leading to painful pressure in the eye (rubeosis).

If complications from retinal vein occlusion are not treated, irreversible blindness may occur.

HOW IS RETINAL VEIN OCCLUSION DETECTED?

Your ophthalmologist (Eye M.D.) detects retinal vein occlusion by examining the retina with an instrument called an ophthalmoscope. He or she may also perform fluorescein angiography, a procedure that takes special photographs of the eye, in order to further investigate the blood vessels in your eye.

HOW IS RETINAL VEIN OCCLUSION TREATED?

There is no known cure for retinal vein occlusion, though in some cases laser surgery may be used to reduce the macular edema and stabilize or improve vision. In severe CRVO, laser surgery is used to prevent or treat the abnormal blood vessel growth that can lead to glaucoma.

You may be able to prevent retinal vein occlusion from occurring again by properly managing any health conditions that contribute to this eye problem (such as diabetes, glaucoma or high blood pressure).