How Diabetes Increases Glaucoma Risk: Signs, Impact & Prevention

Having diabetes is all about checking your blood glucose, diet, and overall well-being all the time. But few are aware that diabetes halves the chances of going blind because of glaucoma—an asymptomatic eye disease that can lead to irreversible blindness.

Glaucoma also has a nickname, the “silent thief of sight,” because it will likely be symptom-free until it is in its beginning phase. In patients with diabetes, the risk of getting it is higher because of the damage high blood sugars have on the delicate blood vessels in the eyes.

What Is Glaucoma?

Glaucoma is a group of eye diseases that damage the optic nerve, the nerve within your eye that transmits pictures to your brain. In most instances, it is the result of elevated intraocular pressure (IOP), or above-normal eye pressure. Gradually, this pressure damages nerve fibers and produces gradual loss of vision—often starting at the fringes of vision.

How Does Diabetes Increase Glaucoma Risk?

When blood sugars consistently remain higher over years, they have the potential to damage the body’s blood vessels—blood vessels in the eyes, too. This leads to diabetic eye diseases such as diabetic retinopathy and elevated intraocular pressure, which themselves have the potential to raise the risk for glaucoma.

Some of the most powerful associations between diabetes and risk for glaucoma include:

Inadequate blood supply to the optic nerve, leaving it more vulnerable to damage

• Fluid drainage problems in the eye caused by blood vessel abnormalities
• Increased inflammation and oxidative stress in eye tissues
• Coexistence of other conditions like diabetic retinopathy, which further strain the eyes

Research shows that people with diabetes are twice as likely to develop glaucoma as those without diabetes. The longer you’ve had diabetes, the greater your risk.

Diabetic Eye Complications That Can Lead to Glaucoma

1. Diabetic Retinopathy

It is a common diabetic complication when the elevated blood sugar damages the minute blood vessels of the photoreceptors of the retina (the light-sensitive nerve tissue at the back of your eye). New, abnormal blood vessels can develop subsequently, plugging drainage in the eye, increasing pressure and neovascular glaucoma, a severe form of the disease.

2. Macular Edema

Swelling at the back of the retina (macula) that may obstruct vision. Swelling and fluid may interfere with normal pressure regulation in the eye, resulting in glaucoma.

3. Cataracts

Cataracts form in diabetic patients typically before patients who do not have diabetes. Cataract surgery in diabetic patients will sometimes add to the risk of glaucoma, especially if other eye conditions are present.

These eye conditions require follow-up for diabetes prevention of glaucoma.

What are the Signs and Symptoms of Glaucoma in Diabetics?

Perhaps one of the worst things about glaucoma is that it does not usually develop symptoms until significant damage has already occurred to the vision. But diabetics must be especially vigilant for any change in vision.

Early Symptoms of Glaucoma in Diabetics:

• Slowness at losing side (peripheral) vision
• Blurred or wavy vision
• Difficulty seeing in dim light
• Eye strain or headache
• Halos around light
• Redness or pain in the eyes (in some forms)

Advanced Symptoms or Emergencies:

In a minority of cases, particularly in angle-closure glaucoma or neovascular glaucoma, symptoms may be acute and painful:

• Severe burning eye pain
• Sudden vision loss
• Nausea or vomiting
• Extremely red eyes

Get medical help at once if these symptoms occur to prevent permanent damage.

Forms of Glaucoma That Diabetics Are More Likely To Have

1. Primary Open-Angle Glaucoma (POAG)

This is the most common form, and it develops slowly. Diabetics are most susceptible to POAG, especially if their blood glucose is poorly controlled.

2. Neovascular Glaucoma

This is uncommon but serious and results when new vessels block fluid drainage in the eye. It occasionally forms with severe diabetic retinopathy and is difficult to treat.

3. Angle-Closure Glaucoma

Though less common, this also occurs in diabetics. It is a sudden clogging of drainage channels and a sharp rise in eye pressure and severe symptoms.

How Is Glaucoma Diagnosed in Diabetics?

Early detection is to blame for preventing vision loss. Because diabetes distorts or makes eye symptoms complicated, eye examinations should be done at regular intervals.

Tests Recommended Are:

• Tonometry: Test for intraocular pressure
• Dilated eye examination: Allows viewing of retina and optic nerve
• Visual field exam: Tests loss of side vision
• OCT scan: Detects optic nerve damage and retinal thickness
• Gonioscopy: Tests drainage angle of eye

Diabetics must have a complete eye examination at least once a year—more frequently, if diabetic retinopathy or glaucoma have already been diagnosed.

Can Glaucoma be Prevented in Diabetics?

Even if you can’t always prevent glaucoma, especially if you have a family history, you might reduce your chance of getting glaucoma or getting it early in life by managing diabetes and building good eye health habits.

What You Can Do to Prevent Glaucoma in Diabetes?

You can: 

1. Keep Your Blood Sugar Under Control

• Keep your HbA1c level below 7% (as recommended by your doctor)
• Prevent high blood sugar fluctuations
• Monitor blood sugar often

2. Monitor Blood Pressure & Cholesterol

Diabetic eye damage and glaucoma are made harder to deal with by high blood pressure and cholesterol. Manage them through medication, diet, and exercise.

3. Don’t Miss Eye Exams

Checkups every two years are the best method to detect trouble early. Inform your eye doctor you have diabetes—there may be some additional tests.

4. Exercise Regularly

Swimming or brisk walking can reduce eye pressure and enhance blood flow, including to the eyes.

5. Stop Smoking

Smoking increases oxidative stress and damages blood vessels—both of which can worsen eye complications in diabetics.

6. Follow Medication Plans

If you’ve been prescribed eye drops or treatments for glaucoma, stick to them religiously. Skipping medications can cause pressure to rise and accelerate vision loss.

How Is Glaucoma Treated in Diabetics?

Diabetic glaucoma treatment is the same as for anyone else but may need closer observation and individually adjusted treatment, especially in case of pre-existing diabetic retinopathy.

Treatment includes:

• Eye drops: To lower eye pressure
• Oral drugs: Occasionally combined with drops
• Laser therapy: Laser trabeculoplasty for open-angle glaucoma
• Panretinal photocoagulation to decrease abnormal blood vessels in neovascular glaucoma
• Surgery: Trabeculectomy or drainage implants to drain

Minimally invasive glaucoma surgeries (MIGS) for less advanced cases

The presence of diabetes may affect healing time or treatment response, so diabetic patients require personalized care and close follow-up.

Living with Diabetes and Glaucoma: Daily Life and Vision Care

If you’re managing both diabetes and glaucoma, it’s important to build a daily routine that supports your eye health and overall well-being.

Lifestyle Tips:

• Use medication reminders or mobile apps for eye drops
• Use contrast-enhancing lenses or magnifiers to improve vision
• Provide good lighting in the home
• Pursue vision rehabilitation services from your physician if vision impairment is affecting daily activities

With proper treatment, most diabetics with glaucoma are independently safe.

Conclusion

Diabetes doesn’t just impact your blood sugar. The effect on your eyes can be devastating if ignored. As glaucoma is the most preventable form of blindness, awareness, early detection, and ongoing treatment are your best defense.