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Diabetic Retinopathy

Diabetic retinopathy is a disease that occurs when tiny blood vessels in the eye become damaged. These delicate blood vessels are important because they nourish the retina (the nerve layer inside the eye that records what one sees and sends the information to the brain). If these blood vessels become weakened by diabetes, they can bleed or leak causing blurred vision or, sometimes, blindness. Unfortunately, clinicians do not know exactly what causes it.

Who develops diabetic retinopathy?

Diabetic retinopathy refers to retinal damage caused by diabetes. Diabetic retinopathy can occur in both type I (insulin-dependent) and type II (non-insulin-dependent) diabetics. Retinopathy can show up early in the course of diabetes, but on average, it takes 8-10 years to develop changes that are visible in the retina. About 20% of type II diabetics already show some signs of diabetic retinopathy when they are first diagnosed. In both types of diabetes, retinopathy tends to be more severe the longer the person has had the disease.

What are the stages of diabetic retinopathy?

Non-proliferative retinopathy:

There may be no visual symptoms early in this stage, although an eye doctor can detect retinopathy. This is also sometimes called background retinopathy. In this stage, the blood vessels in the retina may leak. This can cause some mild bleeding into the retina or cause fluid to collect within the retina. Fluid that builds up in the central retina (known as the macula) is called macular edema. Macular edema may, in some cases, lead to blurred vision. Edema that threatens the vision requires treatment.

Proliferative retinopathy:

This more serious stage occurs when new blood vessels grow on the retina or optic nerve or into the vitreous humor (the jelly-like fluid filling the eye). These blood vessels may bleed and cause vision loss. If scar tissue forms, it can cause the retina to detach from the back of the eye. Untreated and unchecked, this may lead to severe vision loss and ultimately to blindness. Even with these more serious changes, the patient may not have any symptoms or be aware of any problem.

What is the treatment?

Laser treatment (photocoagulation):

An ophthalmologist uses a laser beam to seal damaged blood vessels and stop them from leaking blood. Laser can also prevent the growth of new vessels seen in proliferative retinopathy. This outpatient procedure can stop or slow vision loss.


An ophthalmologist surgically removes the jelly-like fluid or the vitreous humor from the eye and replaces it with saline. Any scar tissue that has formed is also removed. This procedure must be done in an operating room.

How do you prevent retinopathy?

Yearly exams:

It is very important to have a complete eye exam every year. During the exam, your eye doctor will dilate your eyes and examine your retina. This exam will cause blurry vision and your eyes will be sensitive to light for several hours after the exam. Have a family member or friend drive you home or take public transportation. If you need to drive yourself, be prepared to wait for the effect of the drops to wear off.


Although it is not always easy to treat, you can help delay or prevent the onset or retinopathy by carefully controlling your blood glucose level, your blood lipids (cholesterol and triglyecrides) and your blood pressure. This involves working with your primary care physician and following recommendations for diet and exercise, and taking medication, if needed. Learn how to monitor your blood glucose at home, and check it several times a day. Your best weapon against diabetic retinopathy and blindness is managing your health.

Retina Services

Our physicians offer consultation and the latest treatments in retinal and vitreous diseases. This includes consultation for problems such as age-related macular degeneration, diabetic retinopathy, retinal vascular disease, retinal infections, AIDS-related eye disease, laser surgery, retinal detachment repair, and surgery for macular holes. We are affiliated with the Massachusetts Eye and Ear Infirmary in Boston: all major retinal surgery is performed at the Infirmary.

Most retinal examinations require that the pupils be dilated, which can blur one's vision for several hours. If you believe you may have trouble driving after dilation, please consider having someone accompany you, taking public transportation, or scheduling enough time after your exam for your eyes to readjust. Because of the time required for dilation and the possibility other testing may need to be performed, you should plan on your visit lasting about one-and-a-half hours.