Comparing the Time to Treatment Failure Rate at 1–Year Post–Treatment: Results From a SLT vs. ALT Randomized Clinical Trial

Abstract

Abstract: : Purpose:As part of a randomized clinical trial to compare the efficacy and safety of selective laser trabeculoplasty (SLT) to argon laser trabeculoplasty (ALT), we determined the difference in time to treatment failure on the one year cohort. We defined treatment failure using three criteria: i. IOP drop <20% from baseline, ii. Other procedures done after ALT/SLT (i.e. trabeculectomy, cataract extraction, and laser trabeculoplasties), iii. Increase in number of glaucoma medication from pre–treatment levels. Methods:87 ALT and 89 SLT patients were recruited. The percentage of treatment failure rate was calculated using the Kaplan–Meier life–table method. Cox proportional hazard regression model was employed to control for potential variables that might confound the difference. Results:The failure rate at 1–year post–treatment was 32% and 36% for SLT and ALT respectively. Distributions of Glaucoma type and previous ocular surgeries received were not significantly different between the two groups. Even after glaucoma risk factors were controlled for, there was no significant difference between the failure rates between the SLT and ALT group. The average quarter time to treatment failure was 6 months (25% of the sample failed by 6 months), and the hazard ratio was 1.0920. Conclusions:Based on a time to failure analysis, SLT is equally efficacious to ALT in this randomized clinical trial followed to 1 year post–treatment.

Keywords: laser • trabecular meshwork • clinical (human) or epidemiologic studies: outcomes/complications