Pilocar causes constriction of the pupils (miosis) and reduces pressure within the eye. It is used to treat the increased pressure of open-angle glaucoma and to lower eye pressure before surgery for acute angle-closure glaucoma. It can be used alone or in combination with other medications. Glaucoma, one of the leading causes of blindness in the United States, is characterized by increased pressure in the eye that can damage the optic nerve and cause loss of vision.