Evaluation of retinal microvascular features in patients with amblyopia based on optical coherence tomography angiography: a systematic review and Meta-analysis

Background: The performance of optical coherence tomography angiography (OCTA) in macular microvasculature of patients with amblyopia has been widely studied, but these studies have yielded different and controversial results.Objectives: To investigate retinal microvascular features in patients with amblyopia undergoing OCTA.Methods: PubMed, Embase, and Web of Science were searched for published articles comparing the retinal microvascular features between individuals with amblyopia and controls until April 2022. The mean difference with a 95% confidence interval was used to assess continuous variables.Results: The analysis included 17 studies. The whole vessel density of the superficial capillary plexus (SCPVD) was lower in amblyopic eyes (AE) than in normal control eyes (NE) in 3 x 3 mm2 scans, while the perifoveal vessel density of superficial and deep capillary plexus was lower in 6 x 6 mm2 scans. The whole parafoveal vessel density of deep capillary plexus (DCPVD) and parafoveal-SCPVD were lower in both scans. The comparison between amblyopic eyes and fellow eyes (FE) revealed no statistical difference in all quadrants except the parafoveal and perifoveal-SCPVD and the foveal-DCPVD. Additionally, SCPVD in all quadrants except the fovea and DCPVD in all quadrants except the parafoveal were higher in fellow eyes compared to normal control eyes. No significant difference was found in the foveal avascular area between AE and NE, AE and FE, or NE and FE.Conclusions: The retinal vessel density of superficial and deep capillary plexus in amblyopic and fellow eyes was lower than in normal controls, and differences were more likely discovered using 6 x 6 mm(2) scans. Consequently, OCTA may be utilized as a diagnostic tool to identify and monitor patients with amblyopia.