Open-angle glaucoma is the most common type and accounts for 70-90 percent of all cases. Often there are no noticeable symptoms at early stages, and high intraocular pressure (IOP) is the most significant risk factor or indication that you are developing glaucoma.
This is a chronic, slowly-progressing condition. Many factors, including age, structural defects, damage to the trabecular meshwork and/or other drainage systems in the eye, aqueous humor overproduction, or blockages may be responsible for a rise in IOP.
Open-angle glaucoma is most common later in life, with genes, environment, and lifestyle all contributing. With age, the cells of the trabecular meshwork may not function as well as they used to, or may decline in number.
In the United States, open-angle glaucoma strikes African Americans and Hispanics at higher rates than other ethnic groups.