Glaucoma

What is Glaucoma?

Glaucoma is a disease that causes progressive damage to the optic nerve. The optic nerve transmits visual information from the eye to the brain. Glaucoma is usually (but not always) associated with elevated eye pressure. Diagnosis is made by measurement of eye pressure, examination of the optic nerve appearance, evaluation of the peripheral field of vision, and corneal thickness. Glaucoma typically progresses very gradually with no early symptoms and can lead to blindness if left untreated.

The most common form of glaucoma is called primary open-angle glaucoma (POAG). People with POAG usually have elevated intraocular pressure (IOP) that causes damage to the optic nerve over time.

Some people have a type of glaucoma called normal-tension or low-tension glaucoma. These individuals consistently demonstrate IOP below the normal limit, but still experience optic nerve damage and visual field loss.

A less common form of glaucoma is closed-angle (or narrow-angle) glaucoma. This occurs when the drainage angle of the eye becomes blocked. If the angle becomes completely blocked, the IOP rises quickly resulting in a closed-angle attack. Symptoms of an attack include severe eye or brow pain, redness of the eye, blurred vision, halos, severe headache, and significant nausea/vomiting. Angle-closure is something that must be treated by your ophthalmologist immediately.

Causes and Symptoms of Glaucoma

There is a clear liquid, called aqueous humor, that is made and circulates inside the front portion of the eye. This small amount of fluid must drain from the eye by way of a microscopic drainage system (the trabecular meshwork), at a rate consistent with production of the fluid, to maintain a healthy pressure in the eye. In some cases the drainage system doesn't work properly and the eye pressure will build up to dangerous levels, resulting in optic nerve damage.

For some people, glaucoma may be secondary to another eye condition or disease process, such as a tumor, long term steroid use, eye injury, inflammation of the eye, abnormal blood vessel formation from diabetes, pseudo exfoliation, or pigmentary dispersion.

Glaucoma is a complex disease that can steal your sight very gradually, usually without any early symptoms. As the disease progresses and more damage occurs, blind spots develop in your peripheral vision. These may not be noticeable until the optic nerve has been severely damaged. Unfortunately, damage to the optic nerve is not reversible and your visual field loss is not recoverable.

What is the Treatment for Glaucoma?

If optic nerve damage has occurred treatment will not reverse it. However, some treatments can prevent or slow optic nerve damage if glaucoma is detected at an early stage, or prevent further damage in more advanced cases. The most common treatment is medicated eyedrops prescribed by your eye physician. These drops work in various ways to lower your IOP. Your eye physician will determine which drop is best for you.

Laser treatments, such as argon laser trabeculoplasty and selective laser trabeculoplasty are often used to treat glaucoma in patients that do not respond well to drop therapy. Surgical procedures may also be recommended for patients with severe glaucoma.

One such surgical procedure is goniotomy. The surgeon cuts a tiny opening in the first layer of the eye’s natural fluid draining system, known as the trabecular mesh. This, in turn, allows fluid to exit the eye more freely, lowering eye pressure.

If you have glaucoma, preserving your vision requires strong teamwork between you and your doctor. It is important for the patient to follow the doctor's treatment plan closely. Frequent follow up visits and compliance with eye drops are necessary to prevent progression of the disease and insure the health of the eye.