A laser surgery technique used in glaucoma and ocular hypertension therapy. There are two types of the procedure namely, argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). ALT employs an argon laser in making perforations in the trabecular meshwork, which allows the humor to drain out. It is the most common laser surgery treatment for open-angle glaucoma. SLT applies laser energy to initiate a biological and chemical change in the tissue leading to improved fluid drainage out of the eye.