Less light at the end of the tunnel
Glaucoma is caused by damage to the Optic Nerve. The Optic Nerve carries visual stimuli from the eyes to the back of the brain where information is processed. The Optic Nerve can be damaged in one of two ways: Some people are born with a naturally weak Optic Nerve, which can deteriorate through time, leading to Glaucoma. Others can form Glaucoma when the pressure in the eye (Intraocular Pressure) is elevated. Everyone’s eyes have an intraocular pressure to help the eye maintain its shape and rigidity. This optimal intraocular pressure is between 11 mm Hg and 21 mm Hg. When the intraocular pressure exceeds 21 mm Hg, there is a greater force applied to the delicate nerve fibers leading to the Optic Nerve. The pressure is usually checked by a non-contact Tonometer, better known to the public as the dreaded ‘Air-puff’ Test. The puff of air is much more smooth and less startling with the newer machines.
The greatest risk factors for Glaucoma include aging, family history and race. Patients who have a first degree relative with Glaucoma should make sure they have an annual eye exam. Studies have also shown an increased prevalence of Glaucoma in the African Caribbean1 and Hispanic population2.
Glaucoma is a silent eye disease and can often go undetected for years. It begins by affecting the peripheral vision in the early stages, and leads to severe ‘tunnel vision’ in the end stages. At the beginning, subtle peripheral vision loss can be detected by a Visual Fields Test. The Visual fields machine detects blind spots in one’s field of view, which are unnoticeable when both eyes are open (which is how we perform our day to day tasks). If your Optometrist sees any signs of glaucoma, he/she will perform a Visual Fields Test to make sure you do not have the disease.
There is no cure for Glaucoma; however, if detected early, it can be managed with anti-Glaucoma drops. These drops can prevent Glaucoma from progressing to that end stage of tunnel vision. Your Optometrist will routinely check the pressure in your eyes and assess the Optic nerve for any signs of Glaucoma, hence it is important for routine eye examinations.
1. Fansi AA, Papamatheakis DG, Harasymowycz PJ. Racial variability of glaucoma risk factors between African Caribbeans and Caucasians in a Canadian urban screening population. Can J Ophthalmol. 2009 Oct;44(5):576-81. doi: 10.3129/i09-1302. Varma R, Paz SH, Azen SP, Klein R, Globe D, Torres M, Shufelt C, Preston-Martin S; Los Angeles Latino Eye Study Group.Los Angeles Latino Eye Study (LALES). Ophthalmology. 2004 Jun;111(6):1121-31
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