Glaucoma is a vision-threatening disease that can cause optic nerve damage, most often from high pressure caused by poor drainage of a fluid (aqueous humor), which supplies nutrients to the cornea and lens. Glaucoma is one of the leading causes of vision loss, and involves progressive and irreversible damage to the optic nerve.
There are two basic types of glaucoma. They include:
Open-angle glaucoma is the most common type that occurs in approximately 90 percent of those who suffer from the disease. This condition can develop gradually and be undetected for years, slowly damaging vision.
Closed-angle glaucoma (also called angle-closure glaucoma), which is much more rapid in the onset, affects less than ten percent of glaucoma patients. Symptoms occur suddenly and are much more severe, but vision can be preserved with prompt, effective treatment.
Glaucoma Symptoms
Open-angle glaucoma signs and symptoms include:
- Gradual loss of peripheral vision, usually in both eyes
- Tunnel vision in the advanced stages
Closed-angle glaucoma signs and symptoms include:
- Severe eye pain
- Nausea and vomiting (accompanying the severe eye pain)
- Sudden onset of visual disturbance, often in low light
- Blurred vision
- Halos around lights
- Reddening of the eye
Glaucoma Causes
In open-angle glaucoma, the drainage channels in the angle (called the trabecular meshwork) are partially blocked, causing the aqueous humor to drain out of the eye too slowly. The exact cause of open-angle glaucoma remains unknown.
Closed-angle glaucoma occurs when the iris protrudes forward to narrow or block the drainage angle formed by the cornea and the iris. As a result, aqueous fluid can no longer reach the trabecular meshwork at the angle, so the eye pressure spikes suddenly.
Sometimes, glaucoma can be traced to a known cause, such as eye injury, inflammation, tumor, advanced cataract or diabetes.
Risk Factors
- Intraocular pressure
- Age
- Ethnic background
- Family history
- Medical conditions
Treatment Options for Glaucoma
Fortunately, glaucoma is highly treatable. The key to preventing serious vision loss or blindness from glaucoma is early detection. An annual, fully dilated eye examination is recommended.
Treatment involves medications, laser procedures and/or surgery to lower internal eye pressure by opening drainage passageways for the trapped fluid. A complete annual eye exam is the best and earliest means to detect glaucoma.
In early stages of open-angle glaucoma, medicated eye drops or selective laser trabectuloplasty are usually recommended to lower the eye’s pressure. Laser therapy usually takes approximately 5 minutes and has achieved excellent success rates. When patients undergo cataract surgery, they may have a simultaneous procedure called ECP to lower the eye pressure. Patients that fail these types of treatment are not as common. They may require invasive trabulectomy filtering procedures or tube shunts. The treatment for angle-closure glaucoma, or narrow-angle glaucoma, is generally initiated with laser iridotomy to open the drainage channels of the eye.