New research, led by a team at the National Health and Medical Research Council Centre for Clinical Eye Research, Flinders Medical Centre, Adelaide, Australia, has suggested that significant effects may arise from the design of question formats and response categories used in ophthalmic patient-reported outcome (PROs) instruments. The impact of such differences may lead to difficulties in the comparison of research findings that use different PROs. As PROs are increasingly used both in health care settings and clinical trials, the authors suggest that a future “preferred strategy would be to extract content from the existing items, refine the wording, add new content from other sources (e.g., patient focus groups) and fit all the items to a simple, uniform, and common rating scale”.