What is diabetic retinopathy?

In diabetic retinopathy, elevated sugar (glucose) levels in the blood cause blood vessels in the eye to swell and leak in the retina. New blood vessels may also grow causing further damage. Many people who have diabetes have some form of diabetic retinopathy.

example of normal vision example of vision with diabetic retinopathy

Types of diabetic retinopathy

There are four stages of diabetic retinopathy, ranging from mild to severe. In the first three stages, vision loss may not be noticeable or detected. Eye Diagram

  • Stage 1: Mild nonproliferative retinopathy

    At this stage, tiny blood vessels swell in the retina. Some early leakage may take place.

  • Stage 2: Moderate nonproliferative retinopathy

    Some of the blood vessels that feed the retina become blocked. Leaky blood vessels are more likely.

  • Stage 3: Severe nonproliferative retinopathy

    More blood vessels are being blocked and other areas of the retina are not being nourished as a result. Signals are sent to the body to grow new blood vessels.

  • Stage 4: Proliferative retinopathy

    At this advanced stage, new abnormal blood vessels grow (“proliferate”) along the retina and the clear, vitreous gel inside the eye. These begin to replace old blood vessels that feed the retina. The abnormal vessels have thin fragile walls that leak easily, causing blurred vision, severe vision loss or blindness.

    Vision loss can occur quickly at this stage. The advanced stages of diabetic retinopathy can also increase your vulnerability to developing other eye conditions such as a detached retina, which requires surgery, or glaucoma.

Macular edema may also occur at any stage of diabetic retinopathy. In this associated condition, blood and fluid leaks into the macula, causing it to swell. Macular edema causes vision loss in the central retina, which allows us to see fine detail.

*Photo Courtesy of the National Eye Institute

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