Purpose

There are large variations in how adverse events, safety and tolerability related to intraocular pressure (IOP)-lowering eye drops are reported. Inconsistencies and discrepancies in outcomes and methods lead to missed opportunities when comparing studies and combining results in meta-analyses, making it difficult to translate the findings into the clinic. The purpose of this study is to establish consensus among experts on measured outcomes when conducting future clinical trials examining ocular adverse events, safety, and tolerability in patients treated with IOP-lowering eye drops.

Methods

A Delphi study of 2–4 rounds is conducted. International glaucoma and ocular surface experts are invited to participate. The importance of items is ranked using a 10-point scale (1 as not important, 10 as very important). Background literature is used to identify relevant items to be included in the survey. Items are organized into domains, e.g. visual acuity, with subgroups regarding measurement method. A core group of 8–12 leading experts are recruited prior to generating the first questionnaire. The core group contributes to and reviews the study protocol, the questionnaire, the recruitment, and the final article.

Results

An item is considered important when the mean value of importance is ranked ≥7 and the interquartile range of scores is ≤3. At least 30 experts are required to participate in all rounds to complete the study. Not all domains are expected to reach consensus. Consensus within 90% of the domains surveyed is considered a valid consensus status for conclusion.

Conclusions

Achieving consensus on standardized methods for assessing adverse events, safety, and tolerability of IOP-lowering eye drops will provide a valuable basis for evaluating eye drops in randomized clinical trials. This will then enable systematic reviews, which are most valuable to decision makers.