Diabetes and the Eyes

Ever wonder how your eyes "see"? You see an object when light is reflected off of it and directed back to your eye. The light enters your eye through a clear covering called the cornea. It passes through the lens, which focuses the light onto the retina, the light-sensing tissue at the back of the eye. The retina translates these visual signals into electrical impulses that are sent, by way of the optic nerve, to the brain so we can "see" the image.

The retina is supplied with nutrients and oxygen by tiny blood vessels. If glucose levels are elevated, advanced glycated end products (AGEs) and oxidation cause the tiny blood vessels in the retina to thicken in some parts and weaken in others. This leads to the development of diabetic retinopathy, a disease of the blood vessels of the retina of the eye.

As the tiny blood vessels in the retina become swollen, they leak a little fluid into the center of the retina, which may cause your sight to become permanently blurred. This condition is called background retinopathy. If the retinopathy progresses, the deterioration of your sight will progress as well. To try to supply the retina with nutrients and oxygen, many new, tiny blood vessels grow out and across the eye. This is called neovascularization.

These vessels are very fragile and break easily, causing bleeding into the center of your eye, blocking vision and causing blindness. Scar tissue may also form near the retina, pulling it away from the back of the eye. This stage is called proliferative retinopathy, and it can lead to impaired vision and even blindness.

Treatment for diabetic retinopathy can help prevent loss of vision and can sometimes restore some lost vision or stop the progression of neovascularization. Thanks to modern medicine and laser technology, neovascularization can be treated. A laser beam can be focused on these fragile blood vessels, causing them to clot and stop bleeding. But this has to be done early in the course of the disease to be effective.

While research is progressing on how to alter blood flow in the eyes to prevent the early changes of diabetic retinopathy, the best form of treatment is prevention. It is now well known that there are two essential things you can do to best safeguard your vision: Control your blood glucose levels, and have regularly scheduled eye exams.

Getting eyes examined by a doctor is important to avoid diabetes complications.

Regualr eye exams are crucial if you have diabetes.

Sound medical management of your diabetes by you and your team and regular, yearly eye examinations can all but eliminate retinopathy. What's more, for 95 percent of people with diabetes who are already affected by some abnormal blood-vessel growth, early screening and prompt treatment can prevent blindness.

In addition to retinopathy, people with diabetes can have other eye problems that demand attention. Glaucoma, which is caused by too much pressure in the eye, can occur in anyone and is a problem that is not related to diabetes. However, people with diabetes have a greater risk of developing glaucoma. You may have no symptoms of glaucoma, but it can be diagnosed with a simple test that mea-sures pressure in your eye. If detected, it should be treated promptly. When glaucoma is undetected or left untreated, blindness results, which is yet another reason to have regular eye exams by an eye doctor.

Another common eye problem is a cataract, in which the lens of the eye becomes cloudy. This happens in a lot of people as they get older; however, cataracts are more common in people with diabetes. The cloudy crystals in the lens of the eye are caused in part by AGEs. They can lead to poor night vision and, eventually, blindness if not treated. A cataract is treated by removing the lens and replacing it with an implant. Such surgery is done routinely without complications at surgical centers, and most patients are right back to their usual routine within a day or two.

The latest techniques in modern medicine can indeed help to prevent blindness caused by diabetes. But the key is to catch changes early; that's why regular screening is essential.

Diabetes also can wreak havoc on the kidneys, as you will see in the next section.