Angle-closure glaucoma, also known as narrow-angle glaucoma, is caused by blocked drainage canals in the eye, resulting in a sudden rise of pressure in the eye. This is a much more rare form of glaucoma, which develops very quickly and demands immediate attention.
Angle-closure glaucoma happens when the eye drainage canals get blocked or covered over, just as in something covering a sink drain. With angle-closure glaucoma, the iris is not as wide and open as it should be. The outer edge of the iris bunches up over the drainage canals, when the pupil enlarges too much or too quickly. Symptoms of angle-closure glaucoma may include headaches, eye pain, nausea, rainbows around lights at night, and very blurred vision. According to the American Academy of Ophthalmology, Many people with angle-closure glaucoma develop it slowly. This is called chronic angle-closure glaucoma. There are no symptoms at first, so they don’t know they have it until the damage is severe or unless they have an attack of acute angle closure. One out of three people (30%) with chronic angle-closure will have a sudden blockage, causing an attack.
People who have farsightedness are at an increased risk for acute angle-closure glaucoma because their eyes are smaller, their anterior chambers are shallower, and their angles are narrower.
In the United States, fewer than 10% of glaucoma cases are due to angle-closure glaucoma. In Asia, angle-closure glaucoma is more common than open-angle glaucoma.
Certain races, i.e. Asians and Eskimos, have narrow angles and are more likely to develop angle-closure glaucoma than Caucasians. Angle-closure glaucoma among American Indians is lower than among Caucasians. In Caucasians, angle-closure glaucoma is three times higher in women than in men. In African Americans, men and women are affected equally.