Outcomes Evaluated in Randomized Controlled Trials of Treatments for Dry Eye: A Systematic Review.

Purpose: To initiate the process of core outcome set development for dry eye disease (DED) by conducting a systematic review of all outcomes in randomized controlled trials (RCTs) of treatments for DED. A core outcome set is an agreed-upon minimum set of outcomes that should be measured and reported in all clinical trials in a topic area.

Methods: We searched PubMed and Embase from January 1, 2016 to January 3, 2024 for RCTs of treatments for DED. Post hoc, we decided to focus on recent evidence and excluded RCTs published before 2016. Two independent investigators screened titles and abstracts (initially) and full-text articles (subsequently), resolving conflicts through discussion. We refined a previously developed outcome taxonomy for DED. We extracted all outcome domains and measurement instruments used for those domains in the included sample of RCTs.

Results: Our searches identified 6477 unique records, and we included 300 RCTs. The most frequently used outcome domains across all RCTs were tear film stability (90.6% of RCTs), overall assessment of ocular symptoms (84.3%), corneal staining score (75.7%), tear production (66.0%), conjunctival staining score (39.7%), visual acuity (35.0%), meibomian gland plugging/clogging grade (27.0%), inferior tear film meniscus height (16.0%), and adverse events (28.0%). There was considerable inconsistency regarding measurement instruments.

Conclusions: Variability in outcome measures and instruments used underscores the need for a core outcome set for DED. Our next steps are to begin prioritizing the identified outcomes for a core outcome set for DED.