Glaucoma is a disease of the optic nerve, which transmits the images you see from the eye to the brain. The optic nerve is made up of many nerve fibers (like an electric cable with its numerous wires). Glaucoma damages nerve fibers, which can cause blind spots and vision loss. Glaucoma is often, but not always, caused by a buildup of the pressure inside the eye, known as intraocular pressure (IOP). When the aqueous humor (a clear liquid that normally flows in and out of the eye) cannot drain properly, pressure builds up in the eye. The resulting increase in IOP can damage the optic nerve and lead to vision loss.

The most common form of glaucoma is primary open-angle glaucoma, in which the aqueous fluid is blocked from flowing back out of the eye at a normal rate through a tiny drainage system. It is known as open-angle because the anterior chamber angle, which is the portion of the drainage system visible by examination, appears open. In other words, the outflow blockage cannot be directly seen with typical examination techniques. Most people who develop primary open-angle glaucoma notice no symptoms until their vision is impaired.

Glaucoma causes include elevated eye pressure (intraocular pressure or IOP) due to the eye’s inability to drain fluid efficiently. If the drainage angle is blocked, excess fluid cannot flow out of the eye, causing the fluid pressure to increase. Congenital glaucoma is a rare type of glaucoma that develops in infants and young children. It can be hereditary, and it happens when the eye’s drainage system doesn’t develop fully or correctly before birth.

Glaucoma can often be caused by another eye condition or disease. This is known as secondary glaucoma. Someone who has a tumor or people undergoing long-term steroid therapy may develop secondary glaucoma. Other causes of secondary glaucoma include: eye injury, inflammation of the eye, abnormal blood vessel formation from diabetes or retinal blood vessel blockages, use of steroid-containing medications (pills, eyedrops, sprays) or pigment dispersion.

Glaucoma Risk Factors

  • African or Hispanic heritage
  • Corneas are thin in the center
  • Family members with glaucoma
  • Farsightedness or nearsightedness
  • Diabetes, migraines, high blood pressure, poor blood circulation or other health problems affecting the whole body
  • Over age 40

People with more than one of these risk factors have an even higher risk of glaucoma and should talk with an ophthalmologist. Early detection and treatment can protect your vision.

Glaucoma Treatment

The goal of glaucoma treatment is to lower your eye pressure to prevent or slow further vision loss. Your ophthalmologist will recommend treatment if the risk of vision loss is high. Treatment often consists of eyedrops but can include laser treatment or surgery to create a new drain (and bypass the damaged one) in the eye. Glaucoma is a chronic disease that can be controlled but not cured. Ongoing monitoring (every three to six months) is needed to watch for changes. Ask your eye doctor if you have any questions about glaucoma or your treatment.

eyeSmart® Eye health information from the American Academy of Ophthalmology. The Eye M.D. Association.

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