Glaucoma is an important cause of irreversible blindness in North America and worldwide. In Americans over the age of 40, the approximate median age-adjusted prevalence is 1.6% of Caucasians and 4.6% of African Americans. This prevalence increases with age, and more than quadruples by age 80. The prevalence of blindness in Caucasians and African Americans with glaucoma is 4% and 8%, respectively. These statistics, and the associated morbidity and quality of life implications,