Glaucoma is a group of eye diseases that cause progressive damage to the optic nerve, resulting in loss of vision. The optic nerve transmits visual signals from the eye to the brain. The most common form of glaucoma, primary open angle glaucoma, is associated with an increase in the fluid pressure inside the eye. This higher pressure causes progressive damage to the optic nerve and loss of vision. Advanced glaucoma may even cause blindness. Not everyone with high pressure will develop glaucoma, and many people with normal eye pressure can develop glaucoma. When the pressure inside an eye is too high for that particular optic nerve, glaucoma will develop. There are many types of glaucoma and theories regarding the causes. The exact cause of glaucoma is not knosn and, it cannot currently be prevented.
Who is at risk?
Glaucoma is one of the leading causes of blindness in the U.S. Most forms of glaucoma develop slowly and usually without any symptoms. Many people do not become aware they have the condition until significant vision loss has occurred. It initially affects peripheral or side vision, but can advance to central vision. But, if glaucoma is detected at an early stage and treated promptly, it can usually be controlled with little or no further vision loss. That is why annual optometric examinations are so important for people at risk of glaucoma. People of all ages can develop glaucoma, but it most frequently occurs in:
- Whites and Hispanics over age 60
- Blacks and over the age of 40
- People with a family history of glaucoma
- People who have eye-related risk factors such as eye trauma, thin corneas (front surface of the eye), retinal detachments, eye inflammations, and certain optic nerve appearances
- People who have certain medical conditions such as diabetes and heart disease
Types of Glaucoma
Of the different types of glaucoma, primary open angle glaucoma often develops gradually and painlessly, without warning signs or symptoms. This type of glaucoma is more common among blacks than whites. It can cause damage and lead to blindness more quickly in blacks, making regular eye examinations, including tests for glaucoma, particularly important for blacks over age 35. Another type of glaucoma, acute angle-closure glaucoma, may be accompanied by:
- Blurred vision
- A loss of side vision
- Appearance of colored rings or halos around lights
- Pain or redness in the eyes
How can it be detected?
Regular eye examinations are an important means of detecting glaucoma in its early stages, and will include:
- Tonometry - a simple and painless measurement of the pressure in the eye.
- Ophthalmoscopy - examination of the back of the eye to observe health and appearance of the optic nerve.
- Visual field test - a check for the development of abnormal blind spots.
Glaucoma can usually be treated effectively by usin prescription eye drops or other medicines. In some cases surgery may be necessary. Unfortunately, any loss of vision from glaucoma cannot usually be restored. But, early detection, prompt treatment and regular monitoring are effective in slowing vision loss for many patients.
Protect your eye health and your vision...
Be sure to visit your doctor of optometry regularly.
Above: normal vision.
Below: a scene as it might be seen with glaucoma.
A clear fluid flows continuously in and out of the anterior chamber and nourishes nearby tissues. The fluid leaves the chamber at the open angle where the cornea and iris meet. When the fluid reaches the angle, it flows through a spongy meshwork and leaves the eye.
Photos courtesy: National Eye Institute, National Institutes of Health