Meta-Analysis of Retinal Changes in Unilateral Amblyopia using Optical Coherence Tomography

Abstract

Purpose

To evaluate retinal changes in unilateral amblyopia using optical coherence tomography.

Methods

Major literature databases were searched for relevant studies. The primary outcome parameters were foveal minimum thickness (FMT), mean foveal thickness (MFT), mean macular thickness (MMT), and peripapillary retinal nerve fiber layer (pRNFL) thickness. Efficacy estimates were evaluated by standardized mean difference (SMD) and 95% confidence interval (CI) for changes in the outcomes of interest.

Results

This meta-analysis included 28 clinical trials involving 408 patients. The FMT, MFT, and MMT in the amblyopic eyes was significantly greater than that of the fellow eyes (SMD = 0.22, 95% CI 0.05–0.39, p = 0.011; SMD = 0.21, 95% CI 0.06–0.36, p = 0.005; SMD = 0.21, 95% CI 0.08–0.35, p = 0.002, respectively). Only FMT was significantly increased in the amblyopia group compared with the normal control group (SMD = 0.38, 95% CI 0.19–0.57, p<0.00001). Analysis showed that pRNFL thickness in the amblyopic eyes was thicker than in the fellow eyes (SMD = 0.13, 95% CI 0.02–0.24, p = 0.016). We did not find that those outcome measures differ between strabismic and anisometropic amblyopia.

Conclusions

The pooled evidence indicates that the amblyopic process may involve the retina, especially the macula. A thicker foveola was found in the amblyopic eyes when compared with visually normal control eyes. Further larger-scale studies especially involving emmetropic normal subjects will be valuable.