Glaucoma

Glaucoma is a group of diseases of the optic nerve involving loss of retinal ganglion cells in a characteristic pattern of optic neuropathy. Although raised intraocular pressure is a significant risk factor for developing glaucoma, there is no set threshold for intraocular pressure that causes glaucoma. One person may develop nerve damage at a relatively low pressure, while another person may have high eye pressures for years and yet never develop damage. Untreated glaucoma leads to permanent damage of the optic nerve and resultant visual field loss, which can progress to blindness.  Glaucoma has been nicknamed "the sneak thief of sight". Worldwide, it is the second leading cause of blindness. Glaucoma affects 1 in 200 people aged 50 and younger and 1 in 10 over the age of 80.

While glaucoma may or may not have distinct symptoms, an almost inevitable complication of glaucoma is vision loss. Visual loss from glaucoma usually first affects peripheral vision, but can also affect central vision. Early vision loss is subtle, and is not noticed by the patient. Moderate to severe vision loss may be noticed by the patient by careful examination of the full visual field. This can be done by an optometrist or ophthalmologist using a visual field analyser by closing one eye and examining the level of vision at various places in the visual field, then repeating with the other eye closed. All too often, the patient does not notice the loss of vision until he or she experiences "tunnel vision". If the disease is not treated, the visual field will become more and more narrow, obscuring central vision, and finally progressing to blindness in the affected eye(s).

Waiting for symptoms of visual loss to occur is not optimal care. Visual loss related to glaucoma is irreversible, but can be prevented or slowed by treatment. Those at risk for glaucoma are typically advised to consult with an ophthalmologist or optometrist on a regular basis. With advances in testing, treatment and surgery, most people diagnosed with early glaucoma are able to maintain their vision and function well, which was not always the case in the past.

Although intraocular pressure is only one of the risk factors of glaucoma, lowering it via pharmaceuticals or surgery is currently the mainstay of glaucoma treatment. In Europe, Japan, and Canada laser treatment is often the first line of therapy. In the U.S., adoption of early laser has lagged, even though prospective, multi-centered, peer-reviewed studies, since the early '90's, have shown laser to be at least as effective as topical medications in controlling intraocular pressure and preserving visual field.

...More at Wikipedia

Related Links:

• Glaucoma Research Foundation
• National Eye Institute
• US National Library of Medicine

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