Predicting treatment response in retinal vein occlusions using baseline optical coherence tomography biomarkers: A systematic review

This systematic review examines the prognostic value of baseline optical coherence tomography (OCT) biomarkers in predicting visual acuity (VA) outcomes for eyes with macular edema secondary to retinal vein occlusions (RVO) treated with anti-VEGF therapies, steroids, laser photocoagulation, or combination treatments. VA predictions at 6, 12, and 24 months post-treatment were assessed using a narrative synthesis approach and vote counting based on effect direction relative to a minimal clinically important difference. Certainty of evidence was evaluated using GRADE guidelines. Confounding factors, biomarker variability, and inconsistent outcome measurements were critically analyzed. A total of 116 studies assessing 31 unique OCT biomarkers were included. 'Low' certainty evidence indicated that an intact external limiting membrane (ELM) at baseline predicted better VA at 6 months, while baseline ellipsoid zone (EZ) integrity predicted better VA at 12 months at 5-letter change, however, these associations were not observed at thresholds of 10 and 15 letters. Certainty of evidence was often downgraded due to confounding factors, variability in biomarker definitions, and inconsistent outcomes. These findings highlight OCT biomarkers' potential for prognostication in RVO patients, but underscore the need for standardized definitions and further research to address confounders, improving the reliability and clinical utility of OCT-based biomarkers.