Diabetes is the leading cause of blindness among working-age adults, but it is not the leading cause of blindness overall. Globally, cataracts and uncorrected refractive errors each affect far more people. The distinction matters because it shapes who is most at risk and what kind of prevention actually works.
Where Diabetes Ranks Among Causes of Blindness
The World Health Organization lists the global causes of vision impairment and blindness in this order: uncorrected refractive errors (88.4 million people), cataracts (94 million), diabetic retinopathy (3.9 million), glaucoma (7.7 million), and age-related macular degeneration (8 million). By sheer numbers, cataracts cause more blindness worldwide than anything else.
But those numbers include all age groups, and cataracts overwhelmingly affect older adults. When you narrow the lens to working-age adults, roughly 20 to 65, diabetic retinopathy moves to the top. That’s the statistic the CDC highlights, and it’s the one most often cited in public health messaging. If you’re of working age and living with diabetes, this is the eye condition that poses the greatest threat to your vision.
How Diabetes Damages the Eyes
The retina, the light-sensitive tissue lining the back of your eye, is fed by a dense network of tiny blood vessels. Prolonged high blood sugar weakens these vessels in several ways. First, it kills off pericytes, the cells that wrap around capillaries and hold them in shape. Without that structural support, capillary walls bulge outward into tiny balloon-like pouches called microaneurysms. These are the earliest detectable sign of diabetic eye disease.
At the same time, the cells lining the blood vessels begin to die and the vessel walls thicken. The protective barrier between the bloodstream and the retina starts to break down, allowing fluid and proteins to leak into surrounding tissue. In early stages, this may cause no symptoms at all. Over time, the leaking fluid can pool in the central part of the retina (the macula), blurring your sharpest vision. The body also responds by growing new, fragile blood vessels that are even more prone to bleeding, which can cause sudden and severe vision loss.
Two Stages, Very Different Risks
Diabetic retinopathy is classified into two main stages. The earlier stage, nonproliferative diabetic retinopathy, involves the microaneurysms, leaking vessels, and swelling described above. Vision may still be normal or only mildly affected. Many people stay in this stage for years without realizing anything is wrong.
The later stage, proliferative diabetic retinopathy, is defined by the growth of new, abnormal blood vessels on the retina’s surface. These vessels are fragile and bleed easily. If they bleed into the gel-like fluid filling the eye, you may see dark floaters or experience a sudden blackout of vision. Scar tissue from repeated bleeding can also pull the retina away from the back of the eye, a retinal detachment that requires emergency treatment. Proliferative disease carries a far greater risk of permanent blindness.
Duration of Diabetes Is the Biggest Risk Factor
The longer you live with diabetes, the more likely you are to develop retinopathy. A landmark study published in the American Journal of Ophthalmology found that 47% of patients had some form of retinopathy, and the prevalence reached 100% after 30 years with the disease. That doesn’t mean everyone with long-standing diabetes goes blind, but it does mean virtually everyone develops some degree of retinal change over decades.
Blood sugar control is the most modifiable factor. Poorly controlled blood sugar accelerates every step of the damage process, from pericyte loss to new vessel growth. High blood pressure and high cholesterol also worsen the disease independently.
Diabetes Raises the Risk of Other Eye Diseases Too
Diabetic retinopathy gets the most attention, but diabetes also increases the odds of developing cataracts and glaucoma. Research on older adults found that people with diabetes were about 50% more likely to develop cataracts and 55% more likely to develop glaucoma compared to those without diabetes. These conditions have their own pathways to vision loss and may develop alongside retinopathy, compounding the overall threat to eyesight.
95% of Severe Vision Loss Is Preventable
The most important number in this entire topic: early detection, timely treatment, and appropriate follow-up can reduce the risk of severe vision loss from diabetic eye disease by 95%, according to the National Eye Institute. The problem is that diabetic retinopathy often produces no symptoms until significant damage has already occurred. Screening is the only way to catch it early.
Current guidelines recommend that people with type 2 diabetes get a dilated eye exam at the time of diagnosis, since the disease may have been present for years before it was caught. People with type 1 diabetes should have their first comprehensive eye exam within five years of diagnosis. After that, annual exams are standard. If your blood sugar is well controlled and previous exams have been clean, your eye doctor may stretch the interval to every two years.
Women with preexisting diabetes who become pregnant face an accelerated risk of retinopathy progression. Eye exams are recommended before pregnancy or in the first trimester, then every trimester through delivery and for one year afterward.
What Treatment Looks Like
If retinopathy is caught early, the primary treatment is better blood sugar, blood pressure, and cholesterol management. That alone can slow or halt progression for many people.
When the disease advances to the point where fluid leaks into the macula or new blood vessels start growing, the most common treatment involves injections into the eye that block the signal triggering abnormal vessel growth. These injections preserve central vision in up to 90% of treated eyes. In many cases, they stabilize vision rather than dramatically improve it, which is why catching the disease before significant damage occurs makes such a difference. Some patients maintain stable vision over years of treatment without further decline.
Laser treatment is another option, particularly for proliferative disease. It seals leaking vessels and destroys areas of the retina that are producing the signals for new vessel growth. In advanced cases where bleeding has filled the inside of the eye or the retina has detached, surgery to remove the gel-like fluid and repair the retina may be necessary.
The Numbers Are Growing
Diabetic retinopathy is projected to affect 14.7 million Americans by 2050, driven by rising diabetes rates and an aging population. That trajectory makes screening and early intervention not just a personal health decision but a public health priority. The gap between what is preventable and what actually gets prevented remains wide, largely because so many people with diabetes skip their annual eye exams or don’t know they need one.