Diabetes and the eye

diagram of a normal eye, eye with nonproliferative retinopathy, and eye with proliferative retinopathy.
Erik van Rens, MD

With the diabetic population estimated at 30 million in the US, a growing number of people see their eye doctor with vision loss caused by diabetic retinopathy. Although it takes 5-10 years to develop diabetic retinopathy, many people have diabetes without knowing it and don’t find out until they get an eye exam.

Diabetes will affect the eye in different ways, but disease of the blood vessels in the retina is the most significant, leading to leakage, but also loss of the smallest vessels which supply oxygen to the retina. Most of our patients are aware of daily fluctuations of vision, due to the rise and fall of blood sugar levels.

Many have difficulty reading due to macular edema, a local swelling of the retina. This can be measured with a special scan called OCT; and fluorescein angiography, an in-office study of the retinal vessels, can pinpoint the location of the leakage.

More advanced cases show a progressive loss of blood supply to the retina, and as a result new vessel formations will occur which grow like weeds and do not improve vision.

This in turn will lead to bleeding in the eye with profound vision loss. Treatment begins with trying to get the diabetes as well controlled as possible.

Swelling of the macula can be treated with laser that targets local points of leakage. If the leakage cannot be controlled with laser, injections of special drugs into the eye are the next option. These injections are done monthly initially, and often are necessary for a long time.

Bleeding in the center of the eye will require a trip to the operation room where the eye can be cleaned out from the inside. This is called a vitrectomy, during which the gellike center is removed.

In advanced cases the retina may be detached, and this requires more extensive surgery with gas or oil replacing the vitreous gel. Vision usually is poor at that time.

Patients with diabetes need an eye exam at regular intervals, because early detection and prompt treatment improve the chance of retaining useful vision.

Delaying treatment results in progressive loss of vision, which cannot always be corrected. After all, diabetic eye disease is still the number one cause of blindness in people under the age of 65.

For patients with diabetes it behooves to say that a regular trip to your eye doctor will prevent a lot of problems.