Glaucoma is a group of eye diseases that gradually steal sight without warning. In the early stages of the disease, there may be no symptoms. Experts estimate that half of the people affected by glaucoma may not know they have it. Worldwide, it is the second leading cause of blindness and the leading cause of blindness among African Americans. Vision loss, which initially affects peripheral or “side” vision, is caused by damage to the optic nerve. This nerve acts like an electric cable with over a million wires and is responsible for carrying images from the eye to the brain.
There is no cure for glaucoma—yet. Early detection is vital to stopping the progress of the disease. However, medication or surgery can slow or prevent vision loss. Appropriate treatment depends upon the type of glaucoma among other factors.
It was once thought that high pressure within the eye, also known as intraocular pressure or IOP, is the main cause of this optic nerve damage. Although IOP is clearly a risk factor, we now know that other factors are involved because up to 50% of people with “normal” levels of pressure can have glaucoma. For this reason we no longer do pressure screening outside of the office. “Normal pressure” does not mean that one does not have glaucoma.
High Intraocular pressure
Age. The risk of developing glaucoma increases with each decade after age 40. (Around 1% in your 40s to up to 12% in your 80s)
African and Hispanic Americans are more prone to glaucoma.
Open angle: Open-angle glaucoma accounts for 90% of glaucoma cases in the United States. This type of glaucoma is painless. The only signs are gradually progressive visual field loss with changes in the optic nerve. It tends to progress at a slower rate and the patient may not notice that they have lost vision until the disease has progressed significantly.
Closed angle: Closed-angle glaucoma accounts for less than 10% of cases in the United States, but up to half of cases in other nations (particularly Asian countries). About 10% of patients with closed angle glaucoma present with acute angle closure crises characterized by ocular pain, halos around lights, red eye, high intraocular pressure, sudden decreased vision, and even nausea and vomiting in some cases. Closed angle glaucoma can appear suddenly and constitutes an ocular emergency. An angle closure attach can be “broken” if caught early and laser surgical intervention can often prevent future attacks.
Because no symptoms are associated with open angle glaucoma, it has been nicknamed the “silent thief of sight.” Vision loss normally occurs gradually over a long period of time and is often only recognized when the disease is advanced. Once lost, damaged visual field cannot be recovered. Therefore, annual eye exams are extremely important in preventing vision loss. It is possible to halt the development or slow the progression by medical (eye drops) and/or surgical means but there is no “cure” for glaucoma at present.