Diabetes can affect the eyes in various ways. It may lead to changes in vision according to variations in blood sugars. It can cause early cataract, visual loss due to involvement of the optic nerve (nerve that carries information from the eyes to the brain) and nerve paralysis leading to double vision. The most important way in which diabetes affects the eyes is by affecting the retina: diabetic retinopathy. Retinopathy if not taken care of well can lead to blindness.
Retina is a layer in the back of the eyes which senses the light and is responsible for the clarity and colour of vision. Diabetes can affect the small vessels in the retina causing blockage, leakage and rupture of the blood vessels.
Retinopathy is of various grades. Your doctor must be referring to very early changes in the retina like the small blood vessels developing some bulges (microaneurysms). Even if they are mild, you need to control the risk factors so that they don’t progress.
High blood sugars, high blood pressure and cholesterol are risk factors for retinopathy. The longer the duration of diabetes, the higher the chance of retinopathy. Smoking, anemia and kidney disease can worsen retinopathy.
The vision may remain normal during the earlier stages of diabetic retinopathy. However, the disease can progress without your knowledge. Early diagnosis can caution you to observe more strict control of your diet, exercise, insulin regime and monitoring. You can even treat this with LASER or various other medicines if there is a high risk of progression.
You should check annually for diabetic retinopathy. In case you develop any of the features of retinopathy, your eye doctor may ask for special investigations and more frequent follow up.
The eye doctor will first check your vision. The pupils need to be dilated before the entire fundus can be seen by the doctor with an ophthalmoscope. The doctor may do a fluorescein angiography to see the blood vessels in the retina clearly. This involves injecting a dye into the blood vessels before a special camera is used to take photographs of the retina.
The treatment for diabetic retinopathy is based on the stage of the disease and risk of progression. LASER photocoagulation and anti VEGF injections. In LASER photocoagulation, the eye care professional makes tiny burns on the retina with a special laser. These burns seal the blood vessels and stop them from growing and leaking. The sooner retinopathy is diagnosed, the more likely these treatments will be successful. The best results occur when sight is still normal.
In intravitreal injections, the drug (Ranibizumab and Bevacizumab) is injected into the vitreous of the eye. This helps to reduce the edema and shrink the new blood vessels formed.
Side effects of scatter photocoagulation are usually minor. They include several days of blurred vision after each treatment and possible loss of side (peripheral) vision.
The LASER will arrest leaking from the blood vessels in the eye and destroy the overgrown blood vessels (proliferative retinopathy). The aim of LASER photocoagulation if to halt or slow down the progress of retinopathy. It may help stabilize the existing vision. Some patients with macular edema may improve the vision.
When the retina has already detached or a lot of blood has leaked into the eye, photocoagulation is no longer useful. The next option is vitrectomy, which is surgery to remove scar tissue and cloudy fluid from inside the eye. The earlier the operation occurs, the more likely it is to be successful. When the goal of the operation is to remove blood from the eye, it usually works. Reattaching a retina to the eye is much harder and works in only about half the cases.
Our ophthalmology services screen for diabetic retinopathy for all patients with diabetes. We will get your metabolic status controlled to prevent the onset and progress of diabetic retinopathy.