Glaucoma Diagnosis

Normally the eye produces fluid (aqueous humor) which after bathing the internal structures of the eye, is drained from the eye.

• The normal eye maintains an internal pressure of between 12 and 22 mm of Mercury. In patients with glaucoma, the intraocular pressure is often elevated as a result of a decrease in the ability of the eye to adequately drain the intraocular fluid.
• "Normal" intraocular pressure is, however, only a statistical average. Some patients have elevated intraocular pressure and no glaucoma while other patients may have normal intraocular pressure and have glaucoma.
• Intraocular pressure readings are often used as a screening method to identify those patients who are increased risk of developing glaucoma. An intraocular pressure test alone is a poor determinate as to whether a patient has glaucoma or not.

The second major factor considered in evaluating a patient for glaucoma is the peripheral (side) visual field. Glaucoma is a disease which does not affect the clearness of the central vision until it is very advanced. The earliest changes experienced in glaucoma is a decrease in the sensitivity of the visual field (peripheral vision).
Sophisticated techniques have been developed to very sensitively test the peripheral visual field. Subtle changes in the visual field test may be an early sign of the development of glaucoma.

A number of other risk factors are considered in evaluating patients who have otherwise borderline findings. Risk factors which contribute to the potential development of glaucoma include race, age, family history of glaucoma, and the presence of other eye diseases which may secondarily result in glaucoma or elevated pressure.