What Is Glaucoma?

Reviewed by: HU Medical Review Board | Last reviewed: March 2021.

Anyone can get the eye disease glaucoma. It is the leading cause of blindness in people over 60 and is twice as likely in people with diabetes. With glaucoma, fluid builds up in the eye. This increases pressure, which damages the optic nerve. The optic nerve connects the eye to the brain and sends signals so you can see.1

Glaucoma and type 2 diabetes

Doctors do not fully understand how diabetes and glaucoma are connected. But they do know that early treatment can prevent blindness.

Types of glaucoma

The most common types of glaucoma in people with diabetes are:1,2

  • Open-angle glaucoma
  • Closed-angle glaucoma

Open-angle glaucoma is the most common type. It builds slowly when the eye does not drain fluid as well as it should. This causes pressure to build over time and starts to damage the optic nerve. There are no warning signs or symptoms. As glaucoma gets worse, the person may see blind spots in their peripheral (side) vision. This may be described as tunnel vision.

Closed-angle glaucoma may build slowly over time. However, sometimes it happens when eye pressure builds quickly. This is an emergency. You should call your doctor or go to the emergency room right away if you have any of these signs:1

  • Vision suddenly becomes blurry
  • You feel severe eye pain
  • You see rainbow-colored rings or halos around lights

You may also have a headache, feel sick to your stomach, or vomit. This type of glaucoma needs to be treated immediately to prevent blindness.


Glaucoma is diagnosed by a type of eye doctor called an ophthalmologist. To diagnose glaucoma, and other eye diseases, your doctor will:3

  • Look at the back of your eye with a bright light
  • Check to see how well you see at the center of your vision and off to the sides
  • Check the pressure of your eye by pushing or blowing on your eye with a special tool

People with diabetes and a family history of glaucoma should get eye exams at least once a year.


Glaucoma can be treated several ways, including:2,3

  • Eye drop medicine
  • Laser therapy
  • Other surgery

The type of treatment you get will depend on the type of glaucoma you have and how severe it is. As with any medicine, there are risks and benefits that your doctor will discuss with you.

If your doctor prescribes eye drops, it is important to use them every day to control the disease. It is common for glaucoma medicines to interact poorly with other drugs. Talk with your doctor and pharmacist about how to avoid drug interactions.

Some people need a second eye drop medicine or laser therapy to remove fluid from the eye. Other surgeries are used less often and usually to treat severe glaucoma.3

If you have been diagnosed with glaucoma, you will need regular eye exams to track how well your treatment is working.

Things to know about diabetic eye disease

People with diabetes are more likely to have glaucoma and other eye diseases, including:

Regular eye exams are the best way to prevent and control diabetic eye diseases like glaucoma.

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