Open-angle glaucoma is the more common of two main types of glaucoma. Glaucoma is an eye disease in which the optic nerve is damaged. Usually, high pressure inside the eye causes the damage.
Eye pressure builds up when fluid that normally flows out of the eye flows out too slowly.
Without treatment, the high pressure can damage the optic nerve and cause blindness. This fluid nourishes your eye and helps to keep its shape. It is not known what causes the fluid to drain out too slowly. One type of open-angle glaucoma is caused by injury to the eye. It may show up months or years after the injury.