PURPOSE: The purpose of this study is to establish consensus among experts on outcomes and methods to be used in clinical trials to assess adverse effects of anti-glaucomatous eye drops. DESIGN: Modified Delphi method. METHODS: Clinical experts from Europe, North America, South America, the Middle East, and Asia were invited to participate in 2 sequential web-based surveys administered from June 27 to August 29, 2021. A total of 91 clinical experts were invited to participate. Of these, 71 (78%) experts from 23 different countries accepted the invitation and answered the first questionnaire. The importance of items was ranked using a 10-point scale (1 as not important, 10 as very important). RESULTS: A total of 84 items were rated in round one by 71 participants. Of these, 68 (81%) reached consensus. In round 2, 19 items, including 3 additional items, were rated by 53 (75%) participants. Consensus was reached in 98% of investigated items. Eight outcomes were agreed as important to assess when conducting future trials: ocular surface, dryness, epithelial damage, local adverse effects related to eye drops as reported by patients, periocular surroundings and eyelids, quality of life questionnaires, hyperemia, visual acuity, tear film, and anterior chamber inflammation. CONCLUSION: We propose a consensus-based series of outcomes and assessment methods to be used in clinical trials assessing adverse effects of antiglaucomatous eye drops. This, we hope, will improve the comparability of results from future trials and thus facilitate meta-analyses and progress in this field.