Diabetes affects millions of Americans, and the eyes are among its most vulnerable targets. Diabetic eye disease — including diabetic retinopathy, diabetic macular edema, glaucoma, and cataracts — is the leading cause of new blindness among working-age adults in the United States. The difficult reality is that significant vision loss from diabetic retinopathy is largely preventable with regular eye exams and good diabetes management — yet many people with diabetes do not receive the annual dilated eye exams that could catch these problems before permanent damage occurs.
How Diabetes Damages the Eyes
The retina is lined with an intricate network of tiny blood vessels that supply oxygen and nutrients to the light-sensitive cells responsible for vision. Chronically elevated blood sugar levels damage the walls of these blood vessels, making them leaky, fragile, and prone to blockage. Over time, damaged vessels can bulge into tiny balloon-like pouches (microaneurysms), leak fluid or blood into the retinal tissue, or close off completely, cutting off blood supply to areas of the retina.
In response to reduced blood flow, the retina sometimes triggers the growth of new, abnormal blood vessels — a process called neovascularization. These new vessels are structurally weak and prone to bleeding into the vitreous gel that fills the eye, causing sudden, severe vision loss. They can also lead to tractional retinal detachment and neovascular glaucoma, both of which are very difficult to treat.
Stages of Diabetic Retinopathy
Non-proliferative diabetic retinopathy (NPDR) is the early stage, characterized by microaneurysms, retinal hemorrhages, and vascular changes that do not yet involve abnormal new vessel growth. Vision is often unaffected at this stage, which is exactly why regular exams are so critical — finding changes at this point allows for intervention before vision is threatened.
Proliferative diabetic retinopathy (PDR) is the advanced, vision-threatening stage in which abnormal new blood vessels grow. This stage requires urgent treatment.
Diabetic macular edema (DME) can occur at any stage. It involves fluid accumulation in the macula — the area of the retina responsible for central, detailed vision — and is a leading cause of vision impairment in people with diabetes. DME can be subtle in its early stages, with only mild blurring, or it can cause significant central vision loss.
How It Is Detected
Annual dilated eye exams are the gold standard for detecting diabetic retinopathy. Dilation allows your eye doctor to see the entire retina clearly. Optical coherence tomography (OCT) provides cross-sectional imaging of the retinal layers and is particularly useful for detecting and monitoring macular edema. Fundus photography creates a wide-field record of the retina that can be compared over successive visits to track progression. Fluorescein angiography uses an injectable dye to map blood flow through the retinal vessels and identify areas of leakage or blockage.
Treatment Options
Laser photocoagulation has been used for decades to seal leaking blood vessels and destroy areas of retina that are producing angiogenic signals. Focal and grid laser treatment is used for certain patterns of macular edema. Panretinal photocoagulation treats proliferative retinopathy by destroying peripheral retinal tissue that is driving the growth of abnormal vessels.
Anti-VEGF injections — drugs that block the vascular endothelial growth factor responsible for abnormal vessel growth — have transformed the treatment of both DME and proliferative retinopathy. These injections are given directly into the eye (with numbing drops) and are highly effective at stabilizing or improving vision in many patients. Common anti-VEGF agents include ranibizumab, bevacizumab, and aflibercept.
What You Can Do
Keeping blood sugar levels as close to target as possible is the single most powerful tool for preventing or slowing diabetic eye disease. Well-controlled hemoglobin A1c levels are directly associated with lower rates of retinopathy development and progression. Blood pressure and cholesterol control matter too, as cardiovascular risk factors amplify the damage diabetes causes to retinal vessels.
Do not miss your annual dilated eye exam. Even if your vision seems fine, significant retinopathy can be present without any symptoms. Early detection and timely treatment preserve vision that would otherwise be lost. Explore our retina care services or find a retinal specialist in our eye care provider directory.