Laser for Glaucoma

Argon laser trabeculoplasty (ALT) was introduced by Wise and Witter in 1979 for the treatment of medically uncontrolled glaucoma. Soon after its introduction, the efficacy and safety of this new technique was studied in a large multicenter prospective clinical trial funded by NEI, Glaucoma Laser Trial (GLT), in which eyes receiving ALT 360 degrees were compared with timolol monotherapy. From 2.5 to 5.5 years of follow-up, GLT demonstrated that trabeculoplasty was as efficacious as medical therapy in treating early POAG. Despite these favorable results, laser therapy did not replace medications as primary therapy in patients with POAG. This was partly due to attrition seen in efficacy over time and introduction of more effective glaucoma medications, namely prostaglandin analogues. The role of laser trabeculoplasty was limited and it was used either as an adjunctive therapy or as an intermediate step between failed medical therapy and surgical intervention. Interest in laser trabeculoplasty has been re-ignited in the past few years with the introduction of selective laser trabeculoplasty (SLT). A number of studies comparing ALT and SLT have shown similar IOP reduction with the two lasers. Because SLT appears to be less destructive histopathologically, a potential benefit of repeatability has been advocated. ALT_vs_SLT