Clinical applications of double-pass optical quality assessment in cataract and refractive surgery: A narrative review

Relevant studies published through April 2026 were identified through searches of PubMed, Web of Science, Scopus, and Google Scholar to summarize the available evidence on objective optical quality assessment. Double-pass technology quantifies retinal image quality using the objective scatter index (OSI), modulation transfer function cutoff frequency, and Strehl ratio. The available evidence demonstrates that elevated OSI values detect early cataract with high sensitivity and specificity and correlate strongly with visual function and surgical outcomes. In myopic eyes, preoperative optical assessment supports surgical planning, with phakic lens implantation generally providing superior optical quality compared with corneal refractive procedures in selected patients. Elevated OSI values in the absence of clinically significant cataract require further evaluation to identify the source of scatter before refractive surgery. Although double-pass technology shows considerable clinical promise, its wider adoption is limited by heterogeneous study designs, protocol variability, and the absence of standardized diagnostic thresholds.