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How Diabetes Causes Blindness


Diabetes damages small blood vessels throughout the body. Diabetic retinopathy happens when high blood sugar damages the blood vessels of the retina. This is the part of the eye that sends images to your brain. Keeping your blood sugar in your target range lowers your risk of getting diabetic retinopathy.

Diabetic retinopathy can lead to poor vision and even blindness. Most of the time, it gets worse over many years.

At first, the blood vessels in the eye get weak. This can lead to blood and other liquid leaking into the retina from the blood vessels. This is called non-proliferative retinopathy. And this is the most common retinopathy. If the fluid leaks into the centre of your eye, you may have blurry vision. Most people with non-proliferative retinopathy have no symptoms.

If blood sugar levels stay high, diabetic retinopathy will keep getting worse. New blood vessels grow on the retina. This may sound good, but these new blood vessels are weak. They can break open very easily, even while you are sleeping. If they break open, blood can leak into the middle part of your eye in front of the retina and change your vision. This bleeding can also cause scar tissue to form. The scar tissue can pull on the retina and cause the retina to move away from the wall of the eye (retinal detachment). This is called proliferative retinopathy. Sometimes people don't have symptoms until it's too late to treat them. That's why having eye examinations regularly is so important.

Retinopathy can also cause swelling of the macula of the eye. This is called macular edema. The macula is the middle of the retina, which lets you see details. When it swells, it can make your vision much worse. It can even cause blindness.

Treatment for diabetic retinopathy

There's no cure for diabetic retinopathy. But treatment often works very well to prevent, delay, or reduce vision loss. The earlier retinopathy is found, the easier it is to treat. And it's more likely that vision will be saved.

Treatment options include:

Laser treatment (photocoagulation).

This usually works very well to prevent vision loss if it's done before the retina has been severely damaged.

Anti-VEGF (vascular endothelial growth factor) or an anti-inflammatory medicine.

Sometimes injections of these types of medicine can help to shrink new blood vessels when diabetic retinopathy is advanced.

Surgical removal of the vitreous gel (vitrectomy).

This may help improve vision if the retina hasn't been severely damaged.

Keeping your blood sugar levels within your target range can help keep eye problems from getting worse.

Many people with retinopathy need to be treated more than once as the condition gets worse.

Major causes of blindness from diabetes

This table shows the major causes of blindness in people who have diabetes and what you can do to help prevent vision loss.

Keeping your blood sugar levels and blood pressure within a target range is always important. You also need regular dilated eye examinations to help find eye diseases early. Finding and treating eye diseases early can help prevent or delay vision loss.

Major causes of blindness associated with diabetes


How it causes vision loss

How to help prevent it

Diabetic retinopathy

It damages the retina, the section of your eye that captures visual information.

  • Keep blood sugar levels in a target range.
  • Control blood pressure.
  • Get regular eye examinations.
  • Treat retinopathy early to keep the disease from progressing.


It increases pressure in the eye, which damages your retina.

  • Get regular eye examinations to check for the disease.


It clouds the lens, the section of your eye that focuses light.

  • Protect your eyes from ionizing radiation (X-rays) and UV radiation (sunlight).
  • Keep blood sugar levels in a target range.


Current as of: March 1, 2023

Author: Healthwise Staff
Medical Review:
Adam Husney MD - Family Medicine
Kathleen Romito MD - Family Medicine