The Connection Between Diabetes and Vision Loss

The main way that diabetes (both types 1 and 2) can affect the eyes is through damage to the retina. The retina is your eye’s light-sensitive lining, positioned at the back of your eye. Like a film in a camera (an old-fashioned camera, that is!), images are formed on the retina and sent to the brain via the optic nerve. Diabetic retinopathy is damage caused to the retina by diabetes. Dangerously elevated levels of blood glucose can lead to microaneurysms in the retina. Bleeding from blood vessels in the retina, combined with the leakage of fluids and fats, can damage the retinal tissue. When the retina is damaged in this way, the images that should form in the retina are not detected properly by the light-sensitive cells, so cannot be sent to the brain. The effect is reduced vision.

Diabetic retinopathy is quite common in people with diabetes, or at least its early warning signs are. The American Diabetes Association has found that nearly all people with type 1 diabetes, and up to 60% of people with type 2 diabetes, exhibit diabetic retinopathy within the first 20 years of having the disease. The situation is likely similar in New Zealand. Being diagnosed with diabetes is no doubt scary. The good news in terms of looking after your vision, though, is that if detected early and monitored properly, full-blown cases of diabetic retinopathy can be avoided in many cases. The early stages of diabetic retinopathy can develop into a more serious condition, called proliferative retinopathy. The New Zealand Association of Optometrists have found that if left untreated, proliferative retinopathy leads to serious vision loss in around 50% of patients. So the answer to preventing vision loss is detection of the problem followed by treatment and management. Diabetic retinopathy can be slowed by paying careful attention to blood glucose levels, blood pressure and cholesterol levels. Your HbA1C (glycated haemoglobin) levels should be checked frequently. Your GP or diabetes specialist will be able to talk you through this (if you’ve lived with diabetes for a long time you’ll already know all about HbA1C!) and let you know what a safe level is for your vision.

A retinal examination is a standard procedure carried out by optometrists. You may have had one even if you’re not diabetic. Some drops will be put in your eye to dilate your retina so that your optometrist can photograph it more easily. (Drops aren’t always required, however). A retinal examination is not invasive, and the drops just feel a little funny for a while. They will make your eyes sensitive to the sun for a few hours, so bring a pair of sunglasses with you and don’t plan on driving home immediately after your appointment. Retinal examinations are recommended once every two years for people living with diabetes. Your optometrist will tell you if they think you need examinations more frequently than this. Of course, if you encounter any sight issues between these two-yearly examinations, contact your optometrist immediately. We’re here to help.