How does diabetic retinopathy progress?

Jeffrey S. Heier, MD
Diabetic retinopathy occurs in two stages. In the earlier stage, known as nonproliferative or background retinopathy, the walls of the small blood vessels become abnormal and weaken. They leak fluid into the surrounding tissue, often leaving deposits of protein and fat called hard exudates. The vessels also develop microaneurysms, tiny bulges or balloons in their walls that tend to leak red blood cells into the retina. As the condition progresses, the abnormal vessels begin to close, robbing the retina of its blood supply. Nerve fibers die off because of poor circulation and lack of oxygen, creating white cottony patches known as soft exudates.

These changes may not necessarily alter your vision. But if the fluid or blood leakage occurs near the macula -- the part of the retina responsible for sharp, central vision -- your sight will be impaired. When fluid leaks into the center of the macula, the macula can swell, blurring vision. This condition is called macular edema, and it can range from minimal to severe.

Severe impairment may also occur when retinopathy advances to the proliferative stage. This is when the severely diminished blood flow causes the damaged retina to try to repair itself by sprouting new blood vessels. However, these new vessels grow abnormally and proliferate into the vitreous humor, the gel-filled compartment of the eye in front of the retina. The new vessels are fragile and prone to leak blood and break. When they bleed into the vitreous humor, they can block the passage of light and cause a sudden loss of vision. The blood is usually reabsorbed, but scar tissue may form. The scar tissue exerts traction on the retina, pulling it away from the back of the eye, which can lead to permanent vision loss. In some cases, the blood does not reabsorb, and surgery may be required to remove the blood and treat the underlying retinopathy.

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Important: This content reflects information from various individuals and organizations and may offer alternative or opposing points of view. It should not be used for medical advice, diagnosis or treatment. As always, you should consult with your healthcare provider about your specific health needs.