Laser peripheral iridotomy is generally recommended for patients with narrow angles, narrow-angle glaucoma, or acute angle closure glaucoma. When LPI is used in patients with narrow angles, it is considered to be a prophylactic procedure that prevents these patients FROM developing acute angle closure glaucoma, which they are at higher risk of developing. This is significant in that an acute attack of angle closure glaucoma usually presents with high eye pressures, pain, and loss of vision. When LPI is used in the treatment of patients who already have acute angle closure glaucoma, it is used to help lower the pressure as well as to prevent another attack of angle closure glaucoma.