Glaucoma is an eye disease that involves increased eye pressure, optic nerve damage and the possible loss of vision. The two major types of glaucoma include primary open-angle and acute angle-closure. Open-angle symptoms include diminishing vision in both eyes and tunnel vision as the disease progresses. Angle-closure symptoms include pain, nausea, low-light visual disturbance, blurred vision or halos around lights, and redness in the eye. Both types of glaucoma can occur on their own or be the result of disorders such as diabetes or cataracts or an injury to the eye.
Doctors diagnose glaucoma with five different tests, the most well known being tonometry, which sends a puff of air into the eye in order to measure its inner pressure; it should fall between 12 to 22 mm Hg. Ophthalmoscopy requires the dilation of the eye in order to visualize the optic nerve's shape and color. Perimetry tests the peripheral vision to determine if it has been compromised. Gonioscopy utilizes numbing eye drops in order to place a lens directly onto the eye and observe the angle between the iris and cornea, which indicates glaucoma when it is closed and blocked or wide and open. Pachymetry measures the thickness of the cornea.Learn more about Vision