Does diabetes cause glaucoma? Diabetes raises the risk of glaucoma but does not cause it in everyone. The National Eye Institute (NEI) says having diabetes nearly doubles your risk of open-angle glaucoma, the most common type, and the Centers for Disease Control and Prevention (CDC) says diabetes can also cause a rarer type called neovascular glaucoma. Early glaucoma often has no symptoms, so the dilated eye exam is how it gets found.
Key takeaways
- NEI, the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), CDC, and the American Academy of Ophthalmology (AAO) all say diabetes roughly doubles the chance of glaucoma. A pooled analysis of 47 studies found a smaller increase, about 1.5 times.
- Glaucoma often has no early symptoms. NEI says half of people with glaucoma do not know they have it.
- Side vision usually fades first, so changes can go unnoticed for years.
- NEI says there is no way to prevent glaucoma and no cure, but treatment can stop it from getting worse.
- Intense eye pain with nausea, a red eye, and blurry vision is an emergency.
Diabetes and Glaucoma: The Short Answer
- Glaucoma is a group of eye diseases. They damage the optic nerve, the nerve at the back of the eye that connects to the brain.
- Diabetes raises the risk. Agencies describe about twice the chance of open-angle glaucoma. Research summaries put the average increase lower.
- Diabetes can cause a specific type. CDC says neovascular glaucoma can happen with diabetic retinopathy.
- Early glaucoma is quiet. Without a dilated exam, it can be missed.
- Treatment protects what vision remains. It does not restore vision already lost.
What Glaucoma Is
NEI describes glaucoma as a group of eye diseases that can cause vision loss and blindness by damaging the optic nerve. The most common type in the United States is open-angle glaucoma, which is what most people mean by the word. NEI says scientists are not sure what causes the most common types, but many people with glaucoma have high eye pressure, and treatments that lower eye pressure help slow the disease.
NEI adds that normal eye pressure varies by person, that some people with high pressure never get glaucoma, and that one type of glaucoma happens in people with normal pressure. That is one reason an eye pressure reading alone does not settle the question.
How Much Does Diabetes Raise the Risk?
| Source | What it says |
|---|---|
| NEI | Diabetes nearly doubles your risk of open-angle glaucoma |
| NIDDK | Diabetes doubles the chances of having glaucoma; chances of glaucoma or cataracts are about twice those of someone without diabetes |
| CDC | People with diabetes are twice as likely to develop open-angle glaucoma |
| AAO | Having diabetes doubles your odds of developing glaucoma |
| Zhao et al., Ophthalmology, 2015 | A meta-analysis of 47 studies and about 3 million people found a pooled relative risk of 1.48 (95% confidence interval 1.29 to 1.71) |
The meta-analysis also found that the risk of glaucoma rose by about 5% for each year since a diabetes diagnosis, and that higher fasting glucose was linked to slightly higher eye pressure. The authors noted that earlier studies had been inconsistent and that results varied widely across studies. The takeaway is that diabetes raises risk, while the exact size of the increase differs depending on the population studied. These numbers describe groups, and they cannot predict your own risk.
The same analysis does not show that lowering blood sugar prevents glaucoma. It shows an association between higher glucose, longer diabetes duration, and higher risk.
The Types of Glaucoma That Matter With Diabetes
| Type | Link to diabetes | Symptoms |
|---|---|---|
| Open-angle glaucoma | Risk is about doubled by diabetes, according to agencies | Often none at first; side vision fades slowly |
| Neovascular glaucoma | Happens with diabetic retinopathy, when new abnormal blood vessels grow on the iris and block fluid from draining, which raises eye pressure (CDC, NEI) | Depends on the stage; needs an eye doctor |
| Angle-closure glaucoma | A less common type listed by NEI; the sources cited here describe no diabetes-specific link | Can come on suddenly with intense eye pain, nausea, a red eye, and blurry vision |
Neovascular glaucoma is tied to retinopathy, which is one more reason the dilated exam also checks the retina. Our guide on whether diabetic retinopathy is reversible explains what treatment can and cannot do for the retina.
Why Early Signs Are Easy to Miss
NEI says glaucoma does not usually have symptoms at first, which is why half of people with glaucoma do not know they have it. Over time you may slowly lose vision, usually starting with side (peripheral) vision, especially the part closest to your nose. Because it happens slowly, many people cannot tell their vision is changing. As it gets worse, you may notice you cannot see things off to the side, and without treatment it can eventually cause blindness.
Open-angle glaucoma usually causes no early symptoms, so the blurry vision many people with diabetes notice is a different problem that deserves its own check: glucose swings, macular edema, or cataracts. Our guide to blurry vision and diabetes covers those causes, and our guide to whether diabetes causes cataracts covers the lens.
Other Risk Factors
Diabetes is one of several. NEI says you are at higher risk if you are over age 60, especially if you are Hispanic or Latino, if you are African American and over 40, or if you have a family history of glaucoma. CDC lists a family history, being over 60, and being African American, Asian, or Hispanic or Latino. NEI suggests encouraging family members to get checked, since glaucoma can run in families.
How Glaucoma Is Found
NEI says eye doctors check for glaucoma as part of a comprehensive dilated eye exam, which is simple and painless, and which includes a visual field test to check side vision. NEI also says that if you are at higher risk, you need a dilated exam every 1 to 2 years.
For people with diabetes, the American Diabetes Association (ADA) says adults with type 2 diabetes should have a dilated, comprehensive exam at diagnosis, and at least yearly once any retinopathy is present. Our guide to how often diabetics should get an eye exam explains the schedule and what to expect.
Treatment and What It Can Do
NEI says doctors use medicines, usually eye drops, laser treatment, and surgery. It says treatment will not undo damage to your vision but can stop it from getting worse, so starting treatment right away matters. NEI offers these tips for people who are treated:
- If your doctor prescribes medicine, take it every day.
- Tell your doctor if treatment causes side effects.
- See your doctor for regular check-ups.
- Ask about vision rehabilitation services if everyday tasks become hard.
Treatments for other diabetes eye problems can also affect eye pressure. AAO says steroid treatments for swelling in the retina can cause spikes in eye pressure, and a retinal specialist may refer you to a glaucoma specialist for monitoring. AAO also says that if you have glaucoma, you have a higher risk of raised eye pressure after cataract surgery. Our guide to what diabetic macular edema is explains why steroid injections come up.
Diabetes Medicines and Eye Pressure
The ADA's Standards of Care in Diabetes—2026 say there are conflicting data on how GLP-1 receptor agonists, a class of diabetes medicines, affect various parts of eye health, including glaucoma. That is a reason to keep your eye doctor informed, not a reason to start or stop any medicine. Ask your prescriber and your eye doctor before changing anything.
Can You Lower Your Risk?
NEI says there is no way to prevent glaucoma, which is why eye exams matter: they let you and your doctor find it before it affects your vision. CDC says the same about prevention and notes that treatment can help stop it from getting worse.
CDC does list habits that protect the eyes in general: managing blood sugar, blood pressure, and cholesterol, and quitting smoking. These support overall eye health and the retina, even though no habit is proven to prevent glaucoma. Our overview of how diabetes affects the eyes puts them in context.
When to Get Help Right Away
NEI lists these sudden symptoms of angle-closure glaucoma: intense eye pain, an upset stomach (nausea), a red eye, and blurry vision. NEI says to go to your doctor or an emergency room now if you have any of them.
NIDDK also says to call a doctor right away for flashes of light, many more floaters than usual, or a curtain-like shadow over your vision, which can signal a detached retina.
Questions to Ask Your Care Team
- Was my side vision tested at my last dilated exam?
- Am I at higher risk because of family history or background, in addition to diabetes?
- How often should I be checked for glaucoma?
- Do any treatments I get for my eyes affect eye pressure?
- Which symptoms should send me to urgent care?
Frequently Asked Questions
Does diabetes cause glaucoma?
Diabetes raises the risk but does not cause glaucoma in everyone. NEI says diabetes nearly doubles the risk of open-angle glaucoma, and CDC says diabetes can also cause neovascular glaucoma in people with diabetic retinopathy.
Can high blood sugar raise eye pressure?
A 2015 meta-analysis found that higher fasting glucose was linked to slightly higher eye pressure, and that the risk of glaucoma was higher with longer diabetes duration. The study shows an association and does not prove that lowering blood sugar prevents glaucoma.
What is neovascular glaucoma?
NEI says diabetic retinopathy can cause abnormal blood vessels to grow and block fluid from draining out of the eye. CDC says these new vessels grow on the iris and raise eye pressure. It needs prompt care from an eye doctor.
What are the first signs of glaucoma?
Often there are none. NEI says glaucoma does not usually have symptoms at first, and when vision is affected, it is usually side vision, especially the part closest to the nose. That is why dilated eye exams matter.
How often should someone with diabetes be checked for glaucoma?
NEI says people at higher risk need a comprehensive dilated eye exam every 1 to 2 years. ADA says adults with type 2 diabetes should have a dilated exam at diagnosis and at least yearly once any retinopathy is present. Ask your eye doctor what schedule fits you.
Can glaucoma be cured?
No. NEI says there is no cure for glaucoma, but early treatment can often stop the damage and protect your vision. Treatment will not undo damage that has already happened.
References
- National Eye Institute. "Glaucoma." Accessed October 2026.
- National Eye Institute. "Diabetic Retinopathy." Accessed October 2026.
- National Institute of Diabetes and Digestive and Kidney Diseases. "Diabetic Eye Disease." Accessed October 2026.
- Centers for Disease Control and Prevention. "Vision Loss and Diabetes." Accessed October 2026.
- American Academy of Ophthalmology. "How Diabetes Affects Your Eye Care." Accessed October 2026.
- American Academy of Ophthalmology. "Surprising Facts About Diabetes and Your Eyes." Accessed October 2026.
- Zhao D, Cho J, Kim MH, Friedman DS, Guallar E. "Diabetes, fasting glucose, and the risk of glaucoma: a meta-analysis." Ophthalmology. 2015;122(1):72–78.
- American Diabetes Association Professional Practice Committee for Diabetes. "12. Retinopathy, Neuropathy, and Foot Care: Standards of Care in Diabetes—2026." Diabetes Care. 2026;49(Suppl. 1):S261–S276. Accessed October 2026.
Next Steps
At your next dilated eye exam, ask whether your side vision and eye pressure were checked and when to come back. Add any family history of glaucoma to the notes you bring.
For adults with type 2 diabetes or prediabetes who want lifestyle education alongside clinical care, the Done With Diabetes™ program offers a lifestyle education protocol that organizes learning about meals, movement, sleep, and stress. It does not diagnose or treat eye conditions or diabetes, interpret test results, change medicines, or replace your care team or your eye doctor.