Dry Eyes
Posted on May 31, 2008
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Dry eye is a common ailment that can occur after refractive surgery. Everyone knows that tears run from our eyes when we cry or when our eyes are irritated. But tears have a much more important everyday function. A film of tears, spread over the eye by a blink, makes the surface of the eye smooth and optically clear. Without our tear film, good vision would not be possible.
1. The Outer Oily Layer
There are three layers in the thin film of tears which coat the surface of the eye, an oily layer, a watery layer, and a layer of mucus. The outermost layer of the tear film is produced by small gland at the edge of the eyelid, called meibomian glands. The main purpose of this oily layer is to smooth the tear surface and reduce evaporation of tears.
2. The Middle Watery Layer
The middle layer, and largest of the three, makes up most of what we ordinarily think of as tears. This watery layer is produced by small glands scattered through the conjunctiva, which is the delicate membrane lining the inside of the eyelid and covering the eyeball, and by the major tear gland called the large lacrimal gland. This layer cleanses the eye and washes away foreign particles or irritants.
3. The Inner Mucus Layer
The innermost layer consists of mucus produced by other cells in the conjunctiva. This layer allows the watery layer to spread evenly over the surface of the eye and helps the eye to remain we. Without mucus, tears would not adhere to the eye.
What are the Different Kinds of Tears?
There are at least two kinds of tear: those that lubricate the eye and those that are produced as a “reaction” to irritation or emotion. Tears, which lubricate the eye, are produced around the clock. Excessive tears occur when a foreign body irritates the eye or when a person experiences extremes of emotion, as in crying.
What is Dry Eye?
Dry eye occurs when the eye can not produce enough tears to keep the eye wet and comfortable. Stinging, burning, scratchiness, stringy mucus, and excess irritation from smoke are usual symptoms. Problem with contact lenses can be cause by dry eyes and make it impossible to wear contact lenses at all. Surprisingly, increased tearing may be a symptom of dry eyes. If the basic tear secretion is below normal, excess tears are produced by the lacrimal gland in response to irritation. Even though the eye is basically dry, overflow tearing can occur, masking the dryness, which caused them in the first place.
What Causes Dry Eye?
Normally, tear production decreases with age. Dry eyes are more common in women, especially after the age of menopause, but can occur at any age in both men and women. Dry eye can also be associated with arthritis. In addition, the inside of the mouth may become dry due to inadequate production of saliva. Swallowing or eating food then becomes difficult. Patient with dry eyes, dry mouth, and arthritis are said to have Sjogren’s syndrome.
Drugs and medication can also cause dry eyes by reducing tear secretion. Since these medications are often necessary, the dry eye condition may have to be tolerated or treated with “artificial tears.” For a listing of drugs that can cause dry eyes, please refer to the last section of this brochure.
How is Dry Eye Diagnosed?
Often an eye care professional is able to diagnose dry eyes by simply examining the eyes. Sometimes tests, which measure tear production, may be necessary. One widely used test involves the placement of filter paper strips under the lower eyelids to measure the rate of tear production under various conditions.
What is the Treatment for Dry Eye?
Replacement with artificial tears is the basis of treatment. Artificial tears are available without a prescription and are used as eye drops to lubricate the eyes and replace the missing moisture. There are many brands of artificial tears on the market, may be used as often as necessary, only once or twice a day, or as often as several times an hour. Solid inserts that gradually release lubricants during the day are also beneficial to some patients.
Conserving the tears, which are naturally produced, is another approach to keeping the eye moist. Tears leave the eye through tear ducts in both eyelids and go down into the nose. These channels may be closed by your eye care professional to create a blockage which will keep the eyes moist for longer periods of time.
Preventing the evaporation of tears can also prove helpful. In winter, when the heat is turned on, a humidifier or a pan of water on the radiator may help add moisture to the air. Wrap-around glasses (illegal to wear while driving in some states) may cut down evaporation of eye moisture due to wind.
Anything that adds to dryness such as an overly warm room, hair dryers, windy days, or anything that adds an irritant to he air will make a person with dry eyes more uncomfortable. Smoking is especially bothersome.
Scratchiness that is bothersome on first opening the eyes in the morning can be treated by using an ointment at bedtime. This can cause temporary blurring of vision, so many people use the least amount necessary to provide relief. Ointments containing Vitamin A are currently under investigation as treatment for dry eye, and early results are encouraging.
Who Can Treat Dry Eye?
A person suffering from dry eye may only need over-the-counter artificial tears, but since extreme dryness can cause serious damage to the eye, an examination and diagnosis by your eye care professional is suggested.
What Drugs Can Cause Dry Eye?
The following drugs may cause dry eye. Brand names may be different from the generic or clinical names listed below:
| Acetophenazine | Diethazine | Methyldopa | Propranolol |
| Amitriptyline | Dimethendene | Methylthiouracil | Protriptyline |
| Antazoline | Diphenhydramine | Metoprolol | Pyrilamine |
| Atropine | Diphenylpyraline | Morphine | Scopolamine |
| Azatadine | Doxylamine | NitrousOxide | Tetrahydrocannabinol |
| Belladonna | Ether | Nortriptyline | THC |
| BetaBlockers | Ethopropazine | Opium | Thiethylperazine |
| Bromphreniramine | Fluphenazine | Oxprenolol | Thioproperazine |
| Carbinoxamine | Hashish | Perazine | Thiordazine |
| Carphenazine | Hexamethonium | Periciazizne | Thirporpazate |
| Chlorisondamine | Homatropine | Perphenazine | Trichloroethylene |
| Chlorpheniramine | Imipramine | Pheniramine | Trifluoperazine |
| Chlorpromazine | Isoretinoin | Piperacetazine | Trifupromazine |
| Clemastine | Marijuana | Practolol | Trimeprazine |
| Cyroheptadine | Mesoridazine | Prochlorperazine | Tripelennamine |
| Desipramine | Methdilazine | Promazine | Triprolidine |
| Dexbrompheniramine | Methotrimeprazine | Promethazine | |
| Dexchlorpheniramine | Metscopolamine | Propiomazine |
If you suffer from dry eye consult your ophthalmologist or your family physician to discuss treatment.
Corneal Disease and Transplants
Posted on May 31, 2008
Filed Under Eye Diseases | 2 Comments
What is the cornea?
The cornea is the clear front window of the eye. It transmits light to the interior of the eye allowing us to see clearly. Corneal injury, disease, or hereditary conditions can cause clouding, distortion, and scarring. Corneal clouding blocks the clear passage of light to the back of the eye, reducing sight sometimes even to the point of blindness. In addition, corneal injury and disease can be very painful.
What causes corneal disease and degeneration?
Infections, whether bacterial, fungal, or viral are frequent causes of severe corneal damage and ulceration. Abnormal steepening of the cornea occasionally follows cataract surgery and some aging processes can also affect the clarity and health of the cornea. Some disorders of the cornea are inherited, and can lead to corneal clouding and loss of sight.
What is a corneal transplant?
If the cornea becomes cloudy, the only way to restore sight is to replace or transplant the cornea. Corneal transplantation (keratoplasty) is the most successful of all tissue transplants. An estimated 15-20,000 corneal transplants are done each year in the United States. The success rate depends on the cause of the clouding. For example, corneal transplants for degeneration following cataract surgery and those for keratoconus both have high success rates, while corneal transplants for chemical burns have lower success rates.
What conditions may require corneal transplants?
- Corneal failure after other eye surgery, such as cataract surgery
- Keratoconus, a steep curving of the cornea
- Hereditary corneal failure such as Fuchs’ corneal dystrophy
- Scarring after infections, especially after herpes
- Rejection after first corneal transplant
- Scarring after injury
What happens during corneal surgery?
Once you and your doctor decide you need a corneal transplant, your name is put on the list at the local eye bank. Before a cornea is released for transplant, the eye bank tests the human donor for the viruses that cause hepatitis and AIDS. The cornea is carefully checked for clarity. Your eye care professional may request that you have a physical examination and other special tests. If you usually take medications, ask your doctor if you should continue using them.
Surgery is often done on an outpatient basis. You will need to skip breakfast, depending on the time of you surgery. Once you arrive for surgery, you will be given eye drops and 
perhaps a sedative to help you relax. Either local or general anesthesia is used, depending on your age, medical condition and eye disease. You will not see the surgery while it is happening. You eye will be held open with a lid speculum or other method.
The eyelids are gently opened. The diseased or injured cornea is carefully removed from the eye. Any necessary additional work within the eye, such as removal of a cataract, is completed. Then the clear donor cornea is sewn into place. When the operation is over, the doctor will usually place a shield over your eye.
What to expect after surgery?
If you are an outpatient, you may go home after a short stay in the recovery area. You should plan to have someone else drive you home. An examination at the doctor’s office will be scheduled for you the following day.
You will need to:
- Use the eye drops as prescribed
- Be careful not to rub or press on your eye
- Use over-the-counter pain medicine, if necessary
- Continue normal daily activities, except exercise
- Ask your doctor when you can begin driving
- Wear eyeglasses or an eye shield as advised by your doctor
If you have any questions about your home care instructions, call you doctor. Your eye doctor will decide when to remove the stitches, depending upon the health of the eye and rate of healing. Usually, it will be several months before the stitches are removed.
What are the risks of corneal transplant surgery?
Corneal transplants are rejected 5% to 30% of the time. The rejected cornea clouds and vision deteriorates. Most rejections, if treated promptly, can be stopped with minimal injury.
Warning signs of rejection are:
- Persistent discomfort
- Light sensitivity
- Redness
- Change in vision
Any of these symptoms should be reported to your surgeon immediately.
Other possible complications include:
- Infection
- Bleeding
- Swelling or detachment of the retina
- Glaucoma
Can these complications be treated?
All of these complications can be treated. A corneal transplant can be repeated, usually with good results, but the overall rejection rates for repeated transplants are higher than for the first transplant. Irregular curvature of the transplanted cornea (astigmatism) may slow the return of vision but can also be treated. Vision may continue to improve up to a year after surgery. Even if the surgery is successful, other existing eye conditions, such as macular degeneration (aging of the retina), glaucoma or diabetic retinopathy, may limit vision after surgery. Even with such problems, a corneal transplant may still be worthwhile.
Requirements of successful corneal surgery
A successful corneal transplant requires care and attention on the part of both patient and physician. However, no other surgery has so much to offer when the unhealthy cornea is deeply scarred or swollen. Corneal transplant surgery would not be possible without the thousands of generous donors and their families who have donated corneal tissue so that others may see.
What happens after surgery?
Return of best vision after corneal transplant surgery may take up to a year after the operation, depending on the rate of healing and the health of the rest of the eye. As in any kind of transplant, rejection of the donated tissue can take place. The major sign of rejection are redness of the eye or worsening of vision. If these occur, promptly return to your eye care professional, even if it is years after the original operation.
Uveitis
Posted on May 31, 2008
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Uveitis is an inflammatory condition that affects the eye or more specifically the uvea. The eye is shaped like a ball, hollow inside with three different layers of tissue surrounding a central cavity. The outer most layer is the sclera (white coat of the eye) and the innermost is the retina (the inner neural-lining of the eye). The middle layer between the sclera and retina is called the uvea. This layer is very rich in its blood supply. When the uvea becomes inflamed, the condition is called uveitis (pronounced U’VE-I-’TIS).
What Is The Importance of the Uvea?
The uvea contains many of the blood vessels which nourish the eye. The uvea consists of three parts; the iris, the cilliary body, and the choroid. Inflammation of the uvea can adversely affect the cornea, lens, the sclera, retina and other vital parts of the eye. Since the uvea borders many important structures in the eye, inflammation of this layer may be sight-threatening and more serious than the more common inflammations affecting the outside layers of the eye.
What Are The Symptoms Of Uveitis?
Symptoms of uveitis include light sensitivity, blurring of vision, pain, and redness of the eye. Uveitis may come on suddenly with redness and pain, or it may present with a slow and insidious onset with little pain or redness, but gradual blurring of vision. Sometimes uveitis can be accompanied by an increase in intraocular pressure (uveitic glaucoma) further increasing eye redness and pain.
Are There Different Kinds?
Yes, when the uvea is inflamed near the front of the eye (in the iris), it is described as iritis. If inflammation exists in the middle of the eye involving the ciliary body, it is called cyclitis. Inflammation in the back of the eye affecting the choroid, is called choroiditis.
What Causes Uveitis?
Uveitis has many different causes. It may result from a virus (such as shingles, mumps, or herpes), a fungus (such as histoplasmosis, or a parasite (such as toxoplasmosis).It also can be associated with auto-immune diseases. Lab work may be helpful in establishing a diagnosis in about fifty percent of cases. In most cases, the cause remains unknown.
Uveitis can also be related to disease in other parts of the body (such as arthritis) or come as a consequence of injury to the eye. Inflammation in one eye can result from a severe injury to the opposite eye (sympathetic uveitis).
How Is Uveitis Diagnosed?
A careful eye examination is extremely important when symptoms occur. Inflammation inside the eye can permanently affect sight, and at times, lead to blindness.
Your eye doctor will use instruments to examine the inside of the eye and often can make a diagnosis on that basis. In some circumstances, blood tests, skin tests, x-rays, and sometimes-even specimens taken surgically from the eye, may assist in establishing the diagnosis. Since uveitis can be associated with disease in the rest of the body, an evaluation and understanding of the patient’s overall medical health is important. This may involve consultation with other medical specialists.
How Is Uveitis Treated?
Prompt treatment is necessary to minimize any loss of vision. Eye drops, especially steroids and pupil dilators, are medications used to reduce inflammation and pain. For deeper inflammation oral medication or even injections may be necessary. Complications such as glaucoma (high pressure in the eye), cataracts (clouding of the lens of the eye), or new blood vessel formation (neovascularization), also may need treatment in the course of the disease. If complications are advanced, conventional surgery or laser surgery may be necessary. Uveitis arising in the front or middle part of the eye (iritis or cyclitis) is commonly more sudden in onset, generally lasting six to eight weeks, and in early stages can usually be controlled by the frequent use of drops. Uveitis in the back part of the eye (choroiditis) is commonly slower in onset and may last longer, and is often more difficult to treat. These cases are best managed by retinal specialists.
Who can treat Uveitis?
Since uveitis is an inflammation inside the eye and is potentially sight-threatening, prompt treatment and proper diagnosis are essential. A case of simple “red eye” may in fact be the earliest sign of a more serious problem. A “red eye” which does not clear up promptly should be evaluated and treated immediately by your eye care physician.
An optometrist or ophthalmologist is educated, trained, and licensed to provide medical care of the eyes. Some eye doctors have specialized training in ocular diseases and uveitis which gives them an advantage in managing more complicated cases of this sight threatening disease.
Glaucoma
Posted on May 31, 2008
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Chronic glaucoma
The most common type of glaucoma is painless. Left untreated, it slowly destroys vision. In fact, most people who have chronic glaucoma are not aware that they are gradually robbed of their eyesight. In most cases, there are no warning symptoms and, by the time vision problems develop, irreversible visual damage may already have occurred.
Acute glaucoma
Is not nearly as common as chronic glaucoma. Unlike the gradual destruction of vision that occurs in the chronic condition, acute glaucoma is marked by sudden severe pain in and around the eye and is often accompanied by nausea and vomiting. In order to alleviate the pressure and prevent further eye damage, emergency treatment, usually laser surgery, is required.
Screening for Glaucoma
In an effort to catch glaucoma early, screening has become widespread and may initially be done by a wide variety of health professionals. Your eye care professional, optometrist, or family doctor may test your eye pressure. It can also be checked in a health care clinic or at your place of work. If the screening suggests that your pressure is elevated, further tests will be performed to establish the diagnosis of glaucoma. Because chronic glaucoma seldom causes symptoms, it’s extremely important for you to have a thorough eye exam around age forty- even if you have no complaints about your vision.
The Glaucoma Exam
Often a general eye examination begins with a visual acuity test that determines how sharp your vision is. Using one eye at a time, you’ll read a chart of letters or numbers of varying sizes from a set distance (often twenty feet). Then you may be asked to view the chart through an instrument known as a refractor. By shining a light through the refractor onto the retina, your doctor can determine if you need glasses.
A slit lamp is a microscope that magnifies and illuminates the cornea, iris, and lens. It aids your doctor in finding conditions such as cataracts and corneal problems. After your vision is checked, your doctor will examine the internal structures of the eye, including the optic nerve. Using an ophthalmoscope, a hand-held instrument, the doctor can see changes in the optic nerve that are characteristic of glaucoma. After the routine examination is completed, a series of specially designed tests are given to help in the specific diagnosis of glaucoma.
The diagnosis of glaucoma is confirmed by an array of diagnostic tools that allow your eye doctor to identify signs of glaucoma long before you have any symptoms. Your doctor may begin with tonometry, which measures the pressure in your eye. Another important test checks your side (peripheral) and central vision. Your doctor may examine the interior structures of your eye using gonioscopy. If glaucoma is diagnosed, your progress will be closely monitored during regular examinations.
Diagnostic Testing
Your examination will test your field of vision, including peripheral and central vision. This test is helpful in determining if your vision has begun to be affected-and, if so, to what extent. Your doctor may use the computerized vision test, the Goldmann perimeter screen test, or the tangent screen test to examine your field of vision. One eye is tested at a time.
During the computerized vision test, the examiner will ask you to place your chin on a stand in front of a screen connected to a computer. While looking straight ahead, you press a button whenever a light appears in view. The computer provides a printout of your field of vision. The Goldmann perimeter screen test is similar except that a computer is not used. An examiner records your responses as you indicate when a light comes into view. With the tangent screen test, the examiner uses a marker in place of a light to map your field of vision.
Another test, called gonioscopy, involves gently placing a special lens that contains a mirror on your eye. The doctor can look inside your eye to see the drainage area that can be a problem in glaucoma. Because the area between the iris and the cornea can be seen, this test is especially helpful in determining whether the angle between the cornea and iris has been narrowed. Gonioscopy may help your doctor diagnose the type of glaucoma you have.
What happens after diagnostic testing?
Once your diagnostic tests have been completed and glaucoma has been diagnosed, your doctor may monitor the progression of the disease with special photographs of the optic nerve. Your doctor can check for progressive enlargement of the optic cup, which indicates continuing damage from the elevated eye pressure. Your doctor may also note blood vessel changes in the optic cup, another sign of glaucoma progression. A special camera for photographing the optic nerve is often used during your eye examinations. Your doctor will advise you how often your eyes will need to be checked.
Occasionally, a person may have a “borderline” eye pressure, which means that, although the pressure is elevated, there is no evidence of glaucoma damage. If you are a glaucoma suspect with a borderline pressure, your doctor may not prescribe medication immediately. Instead, your pressure will require monitoring by your doctor so that if changes do occur, treatment can be started.
Can glaucoma be inherited?
Glaucoma tends to run in families, and if either of your parents or any of your grandparents had it, you have a higher than average chance of developing the disease. Although glaucoma is rare in children, it is a leading cause of blindness in people over forty.
Macular Degeneration
Posted on May 31, 2008
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As the eye looks straight ahead, the macula is the point of the retina upon which the light rays meet as they are focused by the cornea and the lens of the eye. Similar to the film in a camera, the retina receives the images that come through the “camera-like” lens. If the macula is damaged, the central part of the image is blocked as if a blurred area had been placed in the center of the picture. The images around the blurred area may be clearly visible.
Macular degeneration is damage or breakdown of the macula (the point of the retina upon which the light rays meet as they are focused). The eye still sees objects to the side, since side, or “peripheral” vision is usually not affected. Macular degeneration alone does not result in total blindness. However, it can make reading or close work difficult or impossible without the use of special low vision optical aids.
Forms of Macular Degeneration
The most common form of macular degeneration is called dry or atrophic macular degeneration . This form accounts for 70% of all cases, and is associated with aging. It is caused by a breakdown or thinning of the tissues in the macula.
About 10% of macular degeneration falls into a category called exudative macular degeneration. The macula is normally protected by a thin tissue that separates it from very fine blood vessels nourishing the back of the eye. Sometimes these blood vessels break or leak and cause scar tissue to form. This often leads to the growth of new abnormal blood vessels in the scar tissue. These newly formed vessels are especially fragile. They rupture easily and may leak. Blood and leaking fluid destroy the macula and cause further scarring. Vision becomes distorted and blurred, and dense scar tissue blocks out central vision to severe degree.
Other types of macular degeneration are inherited, may occur in juveniles (juvenile macular degeneration), and are not associated with the aging process. Occasionally, injury, infection, or inflammation may also damage the delicate tissue of the macula.
If only one eye is affected, macular degeneration is hardly noticeable in the beginning stages, particularly when the other eye is normal. This condition often involves one eye at a time, so it may be some time before a patient notices visual problems.
Many patients do not realize they have a macular problem until blurred vision becomes obvious. Your eye doctor can detect macular degeneration in the early stages. The doctor examines the macula carefully to see if damage is present.
The Macular Degeneration Exam
The examination will usually include a few more tests:
- A grid test, in which the patient looks at a test page (similar to graph paper), will be used to check for the extent of sight loss spots.
- A color vision test will show whether a patient can tell color differences, and additional tests will help to discover conditions that may be causing the macula to deteriorate.
- Sometimes the eye care professional injects a dye into the patient’s arm, and then takes photos of the retina and macula. The dye helps to clarify any blood vessel abnormality that might be present.
Detection of Macular Generation
Macular degeneration can be detected and diagnosed early by an eye doctor if periodic eye examinations are part of health care. Early detection is important since people may not realize their vision is impaired. There is no cure for the most common form of macular degeneration – dry macular generation. However, ophthalmologic laser surgery has been used to slow the progression of the less common form, but only if this treatment is applied in the very early stages of the condition.
Who can treat Macular Degeneration?
A retinal specialist is the physician best suited to perform surgery in patients with macular degeneration. Both optometrists and general eye care professionals can prescribe nutritional supplements that can slow the progression of the disease. Newer treatment including intraocular steroids and blood vessel growth inhibitors are now being tried in patients with the wet type of macular degeneration with some success.
Macular Degeneration and You
A patient with macular degeneration can be helped. Low vision optical aids often improve vision for people with macular degeneration. Many different types of magnifying devices are available. Aids are best prescribed by an optometrist who specializes in low vision. However, many optometrists can help these patients with simple magnifiers and high power reading glasses. Bright illumination properly directed for reading and close work is often beneficial. Special lamps can also be helpful. Books, newspapers and other items available in large print offer further help.
If you are over the age of 50, or if your family has a history of retinal problems, you should have your eyes checked periodically for signs of eye problems like macular degeneration. Early detection and subsequent treatment, if indicated, may help prevent additional visual loss.
Diabetic Retinopathy
Posted on May 31, 2008
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Diabetes mellitus is a condition which impairs the body’s ability to use and store sugar. Elevated blood sugar levels, excessive thirst with an increase in urine excretion, and changes in the body’s blood vessels are all characteristic of the disease. Diabetes may cause serious changes in the eyes as well. Conditions such as cataracts, glaucoma, occasional blurring and, most importantly, changes in the blood vessels at the back of the eye all may effect sight.
What is Diabetic Retinopathy?
Diabetic retinopathy is a complication of diabetes that affects the eyes. It is caused by the deterioration of the blood vessels nourishing the retina at the back of the eye. These weakened blood vessels may leak fluid or blood, develop fragile brush-like branches, and become enlarged in certain places. When leaking blood or fluid damages or scars the retina, the image sent to the brain becomes blurred.
The risk of developing diabetic retinopathy is high for patients who have had diabetes for a long time. About 60% of patients having diabetes for 15 years or more have some blood vessel damage in their eyes. When diabetes develops at an early age in childhood or teenage years, it is known as juvenile diabetes. Juvenile diabetics are particularly likely to develop diabetic retinopathy at an early age. Only a small percentage of those developing retinopathy, however, have serious problems with vision, and an even smaller percentage ever become blind. In spite of this, diabetic retinopathy is the leading cause of new blindness among adults in the United States, and diabetic patients are said to be 25 times more prone to blindness than non-diabetics.
What is Background Retinopathy?
There are two forms of diabetic retinopathy. In one form, background retinopathy, blood vessels within the retina change. Some vessels decrease in size and others enlarge and form balloon-like sacs, which obstruct the flow of blood through the vessels. These vessels leak and hemorrhage causing swelling of the retina or forming deposits called exudates.
Background retinopathy is considered an early stage of diabetic retinopathy. Fortunately, sight is usually not seriously affected and the condition does not progress in about 80% of diabetic patients. In some cases, however, the leaking fluid collects in the macula, the center portion of the retina, which is responsible for central vision. Straight-ahead images, reading and close work may then become blurred, and loss of central vision can result in legal blindness. Background retinopathy is a warning sign and can progress to more serious, sight-endangering stages.
What is Proliferative Retinopathy?
The second form is proliferative retinopathy. This begins in the same manner as background retinopathy with the addition of new blood vessel growth on the surface of the retina or the optic nerve. These fragile new blood vessels may rupture and bleed into the vitreous, the clear gel-like substance that fills the center of the eye. If the leaking blood clouds the normally clear vitreous, light passing from the lens through the vitreous to the retina is blocked and images are distorted. Additionally, scar tissue forming from the mass of ruptured blood vessels in the vitreous may tighten and pull on the retina, tugging it away and detaching it form the back of the eye. Blood vessels may even grow on the iris and cause a form of glaucoma. Severe loss of sight and even blindness may result from these conditions.
Causes and Symptoms
The cause of diabetic retinopathy is not completely understood; however, it is known that diabetes weakens small blood vessels in various areas of the body. Pregnancy and high blood pressure may worsen this condition in diabetic patients. Though gradual blurring of vision may occur, sight is usually unaffected by background retinopathy, and changes in the eye can go unnoticed unless detected by a medical eye examination.
When bleeding occurs in proliferative retinopathy, the patient has hazy or complete loss of sight. Though there is no symptom of pain, this severe form of diabetic retinopathy requires immediate medical attention.
Detection and Diagnosis
A comprehensive eye examination by your eye doctor is the best protection against the progression of diabetic retinopathy. Diabetic patients should be aware of the risks of developing sight disturbances and should have their eyes examined regularly. (Non-diabetic patients should also have their eyes examined periodically because these examinations help to detect the presence of diabetes and other diseases.)
To detect diabetic retinopathy, the doctor painlessly examines the interior of the eye using an instrument called an ophthalmoscope. The interior of the eye may also be photographed to provide further information.
If diabetic retinopathy is noted, a special method of examination may be used by the retinal specialist to see which blood vessels are bleeding or leaking fluid. First, a fluorescent dye is injected into the patient’s arm. The dye travels through the bloodstream and passes into the blood vessels of the retina. Photographs are taken rapidly as it leaks through the retina’s blood vessels. This technique, called fluorescein angiography, is sometimes used by retinal specialists, and other eye doctors to determine if further treatment is necessary.
Treatment
When diabetic retinopathy is diagnosed, the doctor considers the patient’s age, history, lifestyle, and the degree of damage to the retina before deciding on treatment or continued monitoring of the progress of the disease. In many cases treatment is not needed; in other, treatment is recommended to halt the damage of the diabetic retinopathy and sometimes to improve sight.
Probably the most significant treatment is the use of laser surgery to seal or photocoagulate the leaking blood vessels. This procedure focuses a powerful beam of laser light energy onto the damaged retina. Small burst of the laser’s intense heat stops the bleeding by sealing leaking vessels and forming tiny scars inside the eye. These scars reduce abnormal blood vessel growth and help bond the retina to the back of the eye. This treatment does not require an incision and may be performed in the office. If diabetic retinopathy is detected early, photocoagulation by laser surgery may stop continued damage. Even in advanced stages of the disease, it can reduce that chance that a patient will have severe visual loss.
However, photocoagulation cannot be used in all patients. Depending on the location and extent of diabetic retinopathy, and if the vitreous is too clouded with blood, another treatment must be used. In this surgical procedure, called a vitrectomy, the blood-filled vitreous is removed from the eye and replaced with a clear, artificial solution. About 70 percent of vitrectomy patients notice an improvement in sight. The ophthalmologist may recommend a vitrectomy soon after the vitreous becomes clouded by blood, or wait up to a year to see if the eye clears itself naturally. The timing for each patient depends on the extent of damage to the eye and to the condition of the other eye. If, However, diabetic retinopathy causes the retina to detach from the back of the eye, severe sight loss or blindness can result unless surgery is performed immediately to reattach the retina.
Successful treatment of diabetic retinopathy not only depends on early detection with monitoring and treatment, but also on the patient’s attitude and self-care. All medications should be taken and diet to control diabetes should be followed as directed. Although physical activity presents few problems with background retinopathy, it can increase bleeding in proliferative retinopathy. Exercise for patients with proliferative retinopathy should be moderate, and straining or leaning over with head down should be avoided.
Who can treat Diabetic Retinopathy?
Both general ophthalmologists and retinal specialists can treat diabetic retinopathy. Retinal specialists are ophthalmologists with extra training and experience in treating specifically diseases affecting the retina such as diabetic retinopathy.
Loss of Vision is Largely Preventable
Early detection of diabetic retinopathy is the best protection against sight loss. Even when symptoms are not noticed, the diabetic patient should schedule yearly eye examinations at least once a year. Medical eye examination should be schedule more frequently after diabetic retinopathy is diagnosed. In most cases, with careful monitoring, treatment can begin before sight is affected.
Keratoconus
Posted on May 31, 2008
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Keratoconus is an uncommon condition in which the cornea (the clear front window of the eye) becomes thin and protrudes. Keratoconus literally means a cone shaped cornea. This abnormal shape can cause serious distorting of vision.
What causes Keratoconus?
Despite continuing research, the cause of keratoconus remains unknown. Although keratoconus is not considered an inherited disorder, the chance of a blood relative having keratoconus is thought to be as high as one in ten.
Vigorous eye rubbing, although not the cause of keratoconus, can contribute to the disease process. Therefore, patients with keratoconus should avoid rubbing their eyes.
What are the symptoms of Keratoconus?
Blurring and distortion of vision are the earliest symptoms of keratoconus. Symptoms usually appear in the late teens or early twenties. The disease will often progress slowly for ten to twenty years, and then stop. In the early stages, vision may be only slightly affected, causing glare, light sensitivity and irritation. Each eye may be affected differently. As the disease progresses and the cornea steepens and scars, and vision may become distorted.
A sudden decrease in vision can occur if the cornea swells. The cornea swells when the elastic part of the cornea develops a tiny crack, created by the strain of the cornea’s protruded cone-like shape. The swelling may persist for weeks or months as the crack heals and is gradually replaced by scar tissue.
What is the treatment for Keratoconus?
Mild cases are successfully treated with glasses or specially designed contact lenses. When vision is no longer satisfactory with glasses or contact lenses, surgery, usually a corneal transplant is recommended. Other surgeries such as special heating of the cornea (thermokeratoplasty) or adding additional corneal tissue (epikeratophakia) can also be done.
If sudden corneal swelling occurs, your eye care professional may prescribe eye drops for temporary relief. However there are no medicines known which prevent progression of the disease.
If a corneal transplant is necessary for advanced keratoconus, vision usually improves. As in any eye surgery, complications such as transplant rejection, infection and loss of vision can occur, so results cannot be guaranteed.
Fuchs’ Corneal Dystrophy
Posted on May 31, 2008
Filed Under Eye Diseases | Leave a Comment
Fuchs’ corneal dystrophy is an inherited condition that affects the delicate inner layer (endothelium) of the cornea. The endothelium functions as a pump mechanism, constantly removing fluids from the cornea to maintain its clarity. Patients gradually lose these endothelial cells as the dystrophy progresses. Once lost, the endothelial cells do not grow back, but instead spread out to the fill empty spaces. The pump system becomes less efficient, causing corneal clouding, swelling and eventually, reduced vision.
In the early stages, Fuchs’ patients notice glare and light sensitivity. As the dystrophy progresses, the vision may seem blurred in the morning and sharper later in the day. This happens because the internal layers of the cornea tend to retain more moisture during sleep that evaporates when the eyes are open. As the dystrophy worsens, the vision becomes continuously blurred.
Fuchs’ affects both eyes and is slightly more common among women then men. It generally begins at 30-40 years of age and gradually progresses. If the vision becomes significantly impaired, a corneal transplant may be indicated. Sometimes corneal transplant (also known as penetrating keratoplasty or PKP) is performed along with cataract and intraocular lens implant surgery.
Signs and Symptoms
- Hazy vision that is often most pronounced in the morning
- Fluctuating vision
- Glare when looking at lights
- Light sensitivity
- Sandy, gritty sensation
Detection and Diagnosis
Fuchs’ is detected by examining the cornea with a slit lamp microscope that magnifies the endothelial cells thousands of times. The health of the endothelium cells are evaluated and monitored.
What is the treatment for Fuchs’ Corneal Dystrophy?
Fuchs’ cannot be cured; however, with certain medications, blurred vision resulting from the corneal swelling can be controlled. Salt solutions such as sodium chloride drops or ointment are often prescribed to draw fluid from the cornea and reduce swelling. Another simple technique that reduces moisture in the cornea is to hold a hair dryer at arm’s length, blowing air into the face with the eyes closed. This technique draws moisture from the cornea, temporarily decreases swelling, and improves the vision.
Corneal transplant is indicated when the vision deteriorates to the point that it impairs the patient’s ability to function normally.