WHAT CAUSES GLAUCOMA AND OPTIC NERVE DAMAGE?
No single factor has been identified as a cause of primary open-angle glaucoma. A number of conditions, alone or in combination, are needed to trigger the processes leading to pressure in the first place and then to the nerve damage that destroys sight. The damage done to the optic nerve in glaucoma is triggered in most cases by the excessive pressure on the optic nerve that, over time, causes damage. Because optic nerve damage occurs in glaucoma patients with normal as well as high intraocular pressure, however, researchers are investigating a number of other abnormal events that occur and can damage the optic nerve. [See box Causes of Nerve Cell Death (Apoptosis) and Optic Nerve Damage.] Genetic Factors A number of genes have now been identified as possible factors in many cases of glaucoma. MYOC Gene and Myocilin. A gene called MYOC, formerly the TIGR gene, is responsible for overproducing a sticky protein called myocilin (MYOC), which clogs the trabecular meshwork. (Myocilin is kno
