Diabetes can affect vision and eye health in many ways. High or unstable blood sugar levels can cause temporary changes in the optics of the eye, leading to blurred vision and trouble focusing. Diabetes can cause cataracts, a clouding of the lens inside the eye. The disease can lead to double vision by affecting the nerves and muscles that control the movement and alignment of the eyes. It can even make the eyes more susceptible to glaucoma.
The most important cause of visual impairment from diabetes is diabetic retinopathy. This condition is a result of tiny blood vessels leaking into the retina. Diabetic retinopathy is so common among the diabetic population that up to 20% of patients already have some retinopathy by the time they are diagnosed with diabetes. Nearly all diabetic patients eventually develop this condition. Fortunately, with early detection, most of the visual problems from diabetic retinopathy can be prevented or delayed.
The early stages of retinopathy are called non-proliferative retinopathy. This condition is marked by leakage of fluid or bleeding by the tiny blood vessels in the back of the eye. Eventually the leakage and bleeding can cause the retina to swell and deposits to form. If swelling occurs in the macula, the center of the retina, vision can be affected even if the retinopathy is mild.
The later stages of retinopathy are known as proliferative retinopathy. At this advanced stage, the retina attempts to grow new blood vessels to take the place of the leaking, poorly functioning vessels. Unfortunately, these new blood vessels are fragile. Serious vision problems can develop if these fragile blood vessels bleed. Proliferative retinopathy is very serious and can lead to blindness. The abnormal blood vessels may also grow on the iris, leading to a condition known as neovascular glaucoma.
The good news is that up to 95% of patients with significant diabetic retinopathy can avoid vision loss if they are treated in time. Since early detection of retinopathy is important, it is recommended that all patients with diabetes have a dilated examination at least once a year.
If a patient is at risk of vision loss from retinopathy, they are often treated with a laser treatment to the retina. The goal of this treatment is to prevent abnormal blood vessel growth or reduce swelling in the macula, depending on the type and location of retinopathy.
It has been shown that people with diabetes can significantly reduce their risk of retinopathy in several ways:
- Maintain good control of blood sugar and low hemoglobin A1c
- Keep blood pressure within healthy limits
- Make healthy food choices
- Exercise regularly several days a week
- See an ophthalmologist or optometrist for a dilated exam at least once a year.