Having just undergone laser surgery for diabetic retinopathy, I have also learned that I have cataracts in both eyes. Should I take the chance and have the cataracts removed, since I was told that there is a possibility of vision loss? Can you tell me the percentage of individuals who lose vision after cataract surgery?

J.C.

Diabetes is a disease that affects the body's ability to use sugar. As a consequence, high levels of sugar build up in the bloodstream and tissues, causing damage to important organs. In the eye, diabetes damages the blood vessels that nourish the retina. This can lead to the leakage of blood and blood components into the retina, a condition called diabetic retinopathy. When the leakage affects the central part of the retina, loss of vision can occur. If identified early, such diabetic retinopathy can be stopped with laser treatment.

Since diabetes is one of the most common causes of blindness in the United States, it is very important for diabetics to have eye exams at least once a year. Since the elderly are at greater risk of having both diabetes and a cataract, it is not uncommon to find people with both conditions. In general, diabetics whose retinopathy is under control fare extremely well following cataract-removal surgery.

However, when a patient requires cataract surgery and has active diabetic retinopathy, there is a risk that the retinopathy will grow worse after the surgery. This can occasionally (2-4 percent of cases) result in the loss of vision following cataract surgery. We do not know why uncontrolled diabetic retinopathy may flare after cataract surgery, but we assume that it is related to the inflammation that follows any type of surgery.

It is impossible for me to give you advice on whether to undergo cataract surgery because I do not know the severity of your cataract and the severity of your diabetic retinopathy. If you are unsure of the guidance given by your doctor, you should consider seeking a second opinion from another eye surgeon, preferably one experienced in treating people with diabetes.