Factors Associated with Gonioscopy Before Glaucoma Procedures in the IRIS® Registry

Purpose: To analyze nationwide pre-operative gonioscopy utilization patterns for various glaucoma surgeries and laser surgeries over time using the IRIS ^® Registry (Intelligent Research in Sight). Design: Retrospective cohort study. Participants: All adults who underwent a glaucoma surgery or laser surgery between January 1, 2014 and April 14, 2023. Methods: The first glaucoma procedure from the first eye of each patient was recorded as the index event and time was measured between the most recent pre-operative gonioscopy date to the index event. Baseline demographics, pre-operative clinical characteristics, glaucoma diagnosis, procedure type, and type of subspecialist performing the procedure were collected. Main Outcome Measures: Primary outcomes were the percentage of patients who had gonioscopy before a glaucoma procedure (1) at any prior visit and (2) within 1 year prior to the procedure. Secondary outcomes were the baseline factors that were associated with higher gonioscopy utilization at any prior visit using multivariable logistic regression. Results: The study included 1.1 million patients (mean age 69.5±12.0 years). A majority had an in-office laser surgery (71.9%), while 16.2% had microinvasive glaucoma surgeries (MIGS), 6.5% had a trabeculectomy or tube (traditional), and 4.6% had other glaucoma surgeries. Pre-operative gonioscopy was identified in 64.7% of patients, and 85.0% of those were within 1 year of the index event. In multivariable models, Asian (OR 1.16, 95%CI 1.13–1.18, P <0.001) and Black (OR 1.13, 95%CI 1.12–1.15, P <0.001) racial and ethnic groups were associated with higher odds of gonioscopy compared to White groups. When compared to traditional surgery, MIGS were associated with lower utilization (OR 0.69, 95%CI 0.68–0.71, P <0.001), but in-clinic laser surgeries were not ( P =0.231). Glaucoma subspecialists were more likely to perform pre-operative gonioscopy compared to non-glaucoma subspecialists (OR 2.65, 95%CI 2.62–2.69, P <0.001). Conclusions: Pre-operative gonioscopy use and/or coding is lower than expected, given current guidelines. Among glaucoma procedures, ab interno MIGS were associated with lower pre-operative gonioscopy utilization.