Effect of Bariatric Surgery on Improvement of Retinal Microvasculature in Patients With Obesity: A Systematic Review and Meta-Analysis

Abstract

Obesity is associated with adverse retinal microvascular changes, including narrower central retinal arteriolar equivalent (CRAE), wider central retinal venular equivalent (CRVE) and lower arteriovenous ratio (AVR). Although bariatric surgery improves cardiometabolic risk, its effect on retinal microvascular calibre remains uncertain. We systematically searched the Cochrane Library, PubMed, ScienceDirect and Scopus up to June 2026. Prospective cohort studies reporting CRAE, CRVE or AVR before and after bariatric surgery in patients with obesity were included. Risk of bias was assessed using the Newcastle–Ottawa Scale. Pooled mean differences (MD) with 95% confidence intervals (CI) were calculated using a random-effects model. Eight prospective cohort studies including 283 patients were included. Seven studies contributed to the CRAE and CRVE analyses, and seven contributed to the AVR analysis. Bariatric surgery was associated with a significant increase in CRAE (MD = +4.02 μm, CI [0.26–7.78], p = 0.04). Sensitivity analysis excluding one study showed a stronger and more consistent effect (MD = +5.41 μm, CI [4.59–6.22], p < 0.01). CRVE significantly decreased after surgery (MD = −6.75 μm, CI [−7.42 to −6.07], p < 0.01), while AVR significantly increased (MD = +0.03, CI [0.02–0.05], p < 0.01). Sensitivity analyses suggested that the direction of effect was generally robust, although between-study heterogeneity was present. Bariatric surgery may be associated with favourable retinal microvascular changes in patients with obesity, reflected by increased CRAE and AVR and decreased CRVE.