Diabetes and Your Eyes

People with diabetes mellitus have a higher risk of eye problems. Diabetes can lead to blindness, but most people with diabetes experience nothing more than minor eye disorders. Problems with your vision can be avoided by controlling your blood glucose levels and carefully monitoring your eyes with regular eye exams from your ophthalmologist.
In addition to high blood-sugar levels, diabetes causes changes in the body’s blood vessels that can cause glaucoma, cataracts, and retinopathy.

Diabetic Retinopathy

Diabetic retinopathy is a general term for all disorders of the retina caused by diabetes. The retina is the sensory membrane lining the back wall of the eye that converts images into signals and sends them to the brain. The retina is nourished by blood vessels called capillaries.
Diabetic retinopathy causes changes in the blood vessels of the eye. When blood vessels in the retina are damaged, they may leak or grow abnormally. The results can blur or distort the images that the retina sends to the brain.

Two Types of Diabetic Retinopathy

Nonproliferative Retinopathy:

Nonproliferative retinopathy, also called background retinopathy, is a common, early form of diabetic retinopathy.

Although this stage does not usually cause any loss of vision, the capillary walls may lose their ability to control the passage of substances between the blood and the retina. The retina may become swollen and form fatty deposits within it called exudates.

If the swelling affects the center of the retina where you see fine details, the problem is called macular edema. Vision difficulties in reading and close work may result.

Background retinopathy is considered a warning sign, which after several years could lead to a more serious form called proliferative retinopathy.

Proliferative Retinopathy:

In proliferative retinopathy the blood vessels are so damaged that they close off and new, abnormal blood vessels begin growing on the surface of the retina. This abnormal growth is called neovascularization.

These new blood vessels are weak and may leak blood, blocking vision. This condition is called vitreous hemorrhage.

These abnormal blood vessels may grow scar tissue that can pull the retina away from the back of the eye. This is called a retinal detachment. If left untreated, the retina can become badly damaged before a person notices any change in vision.

Symptoms

Most people with background retinopathy have no symptoms. Even with proliferative retinopathy, the more dangerous form, people may have no symptoms until it is too late to treat them. When bleeding occurs, your sight may become hazy, spotty or even disappear altogether. While there is no pain, proliferative retinopathy is a severe form of the disease and requires immediate medical attention. Pregnancy and high blood pressure may aggravate diabetic retinopathy. For this reason, it is important to have your eyes examined by your ophthalmologist at least once a year.

The longer you have had diabetes the more likely you are to have retinopathy. Most people with insulin- dependent diabetes will have non-proliferative retinopathy at some time. Most people with non-insulin- dependent diabetes will get it as well, but proliferative retinopathy is far less common.

Those who are able to keep blood sugar levels closer to normal are less likely to have retinopathy or will have a milder form. Women are more seriously affected by retinopathy than men.

Treating Diabetic Retinopathy

Only a special eye exam performed in the early stages can detect retinopathy. Your optician who tests your eyeglass prescription will not be able to tell you whether or not you have retinopathy. Only your ophthalmologist can detect this by dilating your pupils to check your retina.

The best protection against diabetic retinopathy is to have yearly medical eye examinations and see your ophthalmologist if you have any unusual vision problems. Although you should remember that serious retinopathy can be present without any symptoms.

Treatment is not always necessary. If treatment is recommended, your ophthalmologist may perform laser surgery, cryotherapy, vitrectomy or retinal repair to prevent blindness.

Laser surgery: Laser surgery may be performed in your ophthalmologist’s office or an out-patient clinic. In a procedure called photocoagulation, a special laser is focused on the damaged retina. Small bursts of the laser’s beam seal the leaking blood vessels and stop them from growing, reducing the macular edema. This procedure does not cure blurry vision caused by macular edema but keeps it from getting worse.

Neovascularization: abnormal blood vessel growth, is treated with scatter photocoagulation, laser surgery where the beam bursts are scattered to the side areas of the retina. The small laser scars reduce the abnormal blood vessel growth and help bond the retina to the back of the eye, preventing retinal detachment.

If the retina has already detached or a large amount of blood has leaked into the vitreous, photocoagulation is no longer useful. Also, scatter photocoagulation only works before bleeding or detachment has progressed very far. The next options are cryotherapy or vitrectomy.

Cryotherapy: In some cases, if the vitreous is clouded by blood cryotherapy, or freezing, of the retina may help shrink the abnormal blood vessels.

Vitrectomy: The ophthalmologist may wait from several months up to a year to see if the blood clears on its own, before going ahead with a vitrectomy. This procedure is performed in the operating room. Vitrectomy is recommended in advanced proliferative diabetic retinopathy. Surgery is conducted to remove scar tissue and cloudy tissue from inside the eye and replaces it with a clear solution.

The procedure is usually successful in removing blood from the eye but only about half of the procedures are successful in reattaching the retina. Most patients have improved sight after surgery.

Retinal repair: Scar tissue may detach the retina from the back of the eye. When this occurs surgery must be performed to reattach the retina to prevent severe sight loss or blindness.

Preventing Eye Problems

The most important steps in preventing eye problems are to maintain blood sugar levels, avoid smoking, bring high blood pressure under control and see your ophthalmologist at least once a year. Although diabetic retinopathy may be present without any symptoms, if you observe changes in your vision see your ophthalmologist immediately.
If a problem is detected before sight is affected your chances for successful treatment are greater.

Contact your ophthalmologist for further information.