OBJECTIVES: To conduct an exploratory analysis comparing cataract surgery plus implantation of the trabecular micro-bypass stent (iStent inject) versus cataract surgery alone in patient-reported outcome (PRO) scores from the Vision Function Questionnaire (VFQ-25) and the Ocular Surface Disease Index (OSDI) by key baseline characteristics.
METHODS: In a pivotal trial of cataract surgery plus iStent inject for the reduction of intraocular pressure (IOP) in subjects with glaucoma and cataracts, the VFQ-25 and OSDI questionnaires were administered to subjects at baseline and months 1, 6, 12, and 24. The percentage of subjects reaching an improvement based on minimally important differences (MID) in PRO scores was derived using half the standard deviation of baseline values. PRO responders were subjects with change from baseline (1) greater than or equal to the MID threshold for the VFQ composite and (2) less than or equal to the MID threshold for OSDI composite. The percentage of PRO responders was compared using a logistic generalized linear mixed model for repeated measures with stratification by (1) baseline IOP (< 25 mmHg and ≥ 25 mmHg) and (2) prostaglandin use (yes/no).
RESULTS: A total of 382 subjects were randomized (N = 237 surgery plus iStent, N = 145 surgery alone) and had baseline and at least one postbaseline score. For composite scores, a greater percentage of responders was observed at all follow-up visits in the iStent inject group compared with the cataract surgery-alone group for the ≥ 25 mmHg IOP and for no prostaglandin use strata, with treatment differences ranging from 10.8% to 21.7% and 13.7% to 28.8%, respectively.
CONCLUSIONS: In a post hoc exploratory analysis of the VFQ-25 and OSDI, cataract surgery plus iStent inject in subjects with high IOP (≥ 25 mmHg) or no prostaglandin use at baseline improved overall ocular symptoms and visual functioning compared with cataract surgery alone.
