Sensation & Perception, 4e

Essay 2.4 Glaucoma

Glaucoma is the term for a family of medical problems in which the optic nerve is damaged in some way. Since this nerve is the sole carrier of information from the eye to the brain, severe optic nerve damage can result in partial or complete blindness. The most common form of glaucoma affects millions of Americans. It is a progressive disease that can be quite effectively stopped in its earliest stages. However, without a proper eye examination, many people fail to notice that anything is wrong until their vision has reached a point where there is no remedy for it.

Normal vision

Vision with glaucoma

The reason for this insidious feature of glaucoma is that axons in the outer portions of the optic nerve, which carry information from the periphery of the retina, are damaged first. This means that early on, glaucoma sufferers are able to see images that fall on the fovea normally, so they may not realize that objects that they are not looking at directly are blurred or invisible. Once damaged, the axons cannot be repaired, and when the vision deficit reaches central vision (interfering with vision noticeably), it is usually far too late for treatment.

A number of institutions host websites on glaucoma. One of the best is provided by the National Eye Institute (part of the National Institutes of Health), which discusses the causes of glaucoma and describes the various methods for correcting the disorder, including laser surgery and conventional surgery. Click the link below to look at their site, and if you or anyone you know is over 40 years old, be sure you or they have a glaucoma exam at least once every two years!

Link

NEI site on glaucoma