Fewer than 10 percent of the 3 million American cases of glaucoma reported in the 2010 U.S. census were attributed to narrow-angle glaucoma, also referred to as angle-closure glaucoma. In the same year, there were over 60 million cases of glaucoma worldwide.
Angle-closure glaucoma can be either acute or chronic. The acute form occurs when there is a sudden block of aqueous humor between the iris and lens, causing severe pain, blurred vision, nausea and vomiting. Angle-closure glaucoma is a medical emergency that can cause blindness in 1 to 2 days and thus warrants immediate medical attention. Chronic angle-closure glaucoma progresses slowly and may cause damage without exhibiting any symptoms.
Due to the increased prevalence with age for both open-angle and angle-closure glaucoma, as well as the aging global population, the worldwide incidence of glaucoma is expected to increase to an estimated 80 million cases by 2020.