Appraisal of patient-reported outcome instruments available for randomized clinical trials in dry eye: revisiting the standards.

Clinical signs in dry eye (DE) often underestimate the severity of the condition, correlating poorly with symptoms and the impact on patients' health-related quality of life (HRQL). Patient-reported outcome (PRO) questionnaires are therefore essential to accurately evaluate the health status of DE patients and the severity of their condition. A comprehensive evaluation of HRQL in addition to clinical signs and visual function is necessary to fully characterize the impact of DE on patients' health. Growing interest in PRO measures and their implementation in clinical trials has resulted in more formal guidance on the design and properties of these instruments. To be scientifically sound and accepted by regulatory authorities, an instrument's development process and its appropriateness for use in the target population, its psychometric properties and responsiveness must be described. To address the recent health authority guidance, this review discusses the design, development methodology, and performance of currently available PRO instruments for DE.