Micropulse Laser Trabeculoplasty (MLT) Versus Selective Laser Trabeculoplasty (SLT) for Treatment of Open Angle Glaucoma

Glaucoma is the 2nd leading cause of blindness worldwide and affects over 2.5 million Americans over the age of 40. It is thought that elevated intraocular pressure causes damage to the optic nerve fibers which leads to silent vision loss in glaucoma. Therefore, the primary approach to managing this disease process is through intraocular pressure reduction with a) topical drops that decrease intraocular fluid production or increase fluid outflow, b) laser therapy to the outflow structures in the eye (trabecular meshwork) to increase fluid egression, c) or incisional surgery with or without placement of setons to create a new pathway for fluid outflow. When medical therapy has been maximized or patients do not tolerate topical therapy, laser trabeculoplasty is common applied to achieve further intraocular pressure reduction. There are two types of laser therapies: argon laser trabeculoplasty (ALT) and selective laser trabeculoplasty (SLT). The former involves applying laser to create outflow pathways in the trabecular meshwork (TM) and induces thermal damage to the TM. The latter selectively applies energy which induces inflammatory restructuring of the TM without creating a burn. Studies have shown comparable results between the two treatment modalities with SLT offering the advantage of repeatable treatment. Studies have also shown laser trabeculoplasty to be comparable to the effect of topical drops in intraocular pressure reduction. Side effects for both types of laser trabeculoplasty include post procedure intraocular pressure elevation and intraocular inflammation which is treated with topical drops after the procedure. This study aims to evaluate the effectiveness of micropulse laser trabeculoplasty in intraocular pressure reduction in patients with open angle glaucoma as compared to conventional selective laser trabeculoplasty. Secondary aims would be to determine whether its reduction is comparable to that of topical intraocular pressure lowering drops, length of therapeutic intraocular pressure reduction, and incidence of side effects commonly encountered with traditional laser trabeculoplasty including intraocular inflammation and intraocular pressure spikes.