In closed-angle glaucoma, the colored part of the eye (iris) and the lens block the movement of fluid between the chambers of the eye. The blockage of fluid causes pressure to build up and makes the iris press on the eye's drainage system (trabecular meshwork). The increased pressure can cause damage to the optic nerve, leading to vision loss and possible blindness. Closed-angle glaucoma is also sometimes referred to as primary angle-closure glaucoma (PACG).