Glaucoma: an introduction

Glaucoma is a vision complication that can be associated with type 2 diabetes, but doesn’t happen exclusively in people with diabetes. It results from a build-up fluid called aqueous humor inside the eye resulting in increased pressure within the eye. Normally, the eye produces and drains aqueous humor through reabsorption into the bloodstream to maintain a constant pressure within the eye. In people with diabetes, retinopathy (blood vessel growth and scarring) can affect the ability of the eye to reabsorb aqueous humor, resulting in increased pressure within the eye. The increase in pressure that occurs with glaucoma can eventually lead to damage to the optic nerve. The two forms of glaucoma associated with diabetes are peripheral glaucoma and neovascular glaucoma.

Peripheral glaucoma is the most common form of the disease in people with diabetes. It generally progresses slowly and is largely without symptoms. It is most common in African Americans and appears to have a strong genetic component (that is, it appears to fun in families). Neovascular glaucoma is relatively rare and is associated with proliferative retinopathy, specifically an increase in pressure within the eye resulting from the formation of new blood vessels within the eye. Presently, there are no effective treatment approaches to neovascular glaucoma.1

Since risk for glaucoma tends to increase as we age, regardless of whether or not you have diabetes, it is important to have your eyes checked regularly with a dilated and comprehensive eye exam performed by an optometrist or ophthalmologist. If you have type 2 diabetes, you should have such an exam after you’ve been diagnosed and at least every 2 years after. This is particularly important for someone with diabetes, where the risk for complications with the potential to lead to glaucoma is increased.

How is glaucoma detected?

During your dilated and comprehensive eye exam, your ophthalmologist or optometrist will use different techniques to determine whether you have glaucoma. He or she will examine the back of your eye using a tool that magnifies the area where the nerves are located to detect signs of nerve damage. Additionally, your doctor will test the pressure within your eye using a specialized tool that pushes or blows on your eye. Your doctor will also inquire whether you are having any problems seeing things in the center and periphery (outside) of your vision.

What are the treatment options for glaucoma?

The treatment approach to glaucoma depends on the type of glaucoma you have and the underlying cause. There are three main approaches to decreasing the pressure within your eye. These include medicine (in the form of eye drops), laser therapy, and surgery.2

Eye drop medications for glaucoma include prostaglandins and beta blockers. Surgical treatment involves making a small incision in the eye to facilitate drainage of aqueous fluid. In some cases, a tiny tube is also placed in the eye for the purpose of drainage.

If your glaucoma is caused by proliferative retinopathy, the treatment approach is typically to use laser therapy to eliminate or control the new blood vessel growth that is getting in the way of normal drainage of aqueous humor. Laser treatment is usually done by an ophthalmologist in an eye clinic or office. Your doctor will first dilate the pupil of your eye and numb the eye using special eye drops. Additionally, you doctor may also apply medication behind your eye to further prevent discomfort during the procedure. During laser treatment, the office will be dimmed and you will sit next to the laser machine. A special lens will be held to your eye and the laser will be used to surgically repair the eye. When the laser is used, you may see flashes of light and feel a stinging sensation. After the procedure, your pupil will remain dilated for several hours and you may feel pain in your eye. Your doctor can offer you medication to ease any discomfort.

Timely detection and treatment is crucial with vision complications associated with diabetes. Appropriate early treatment can make the difference when it comes to whether damage is reversible or permanent. If treatment for proliferative retinopathy is done early enough, the effects of glaucoma can be reversed and eye pressure will return to normal. However, if the drainage system of the eye is scarred from progression of proliferative retinopathy, the resulting glaucoma may be a persistent problem.

Written by: Jonathan Simmons | Last reviewed: May 2014.
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