Corneal Higher-Order Aberrations in Amblyopia

Abstract

Purpose To investigate the amount, type, and role of corneal higher order aberrations in both isotropic and anisometropic amblyopic adult patients. Methods A total of 125 eyes of 78 patients with age ranging from 18 to 67 years (30 patients with unilateral amblyopia, 17 with bilateral amblyopia, and 31 normal eyes considered as the control group) were included. All eyes received a comprehensive ophthalmologic examination that included corneal topographic and aberrometric analysis with the CSO system. The aberrometric study was performed for a 6-mm pupil using different root mean square (RMS) parameters. Additionally, the ocular residual astigmatism (ORA) was also calculated and analyzed. A comparative analysis of the refractive and aberrometric data between groups was performed. Results In the unilateral amblyopia group, statistically significant differences between the amblyopic and non-amblyopic eye were found in cylinder (p=0.003), best-corrected visual acuity (BCVA) (p<0.001), total RMS (p=0.015), and astigmatic RMS (p=0.019). Statistically significant differences between the bilateral amblyopia and control groups were observed in sphere (p=0.025), cylinder (p=0.005), and BCVA (p <0.001). When comparing isometropic and anisometropic bilateral amblyopic eyes, significant differences in total (p=0.025) and astigmatic RMS (p=0.013) were detected. Higher but nonsignificant amounts of primary coma were found in isometropic eyes (0.25 μm anisometropic vs 0.43 μm isometropic, p=0.09). Regarding the ORA, no significant differences between groups were found (p≥0.224). Conclusions In unilateral and bilateral amblyopia, lower order aberrations are the main refractive factors leading to amblyopia. Higher order aberrations could have a bilateral amblyogenic effect in those cases where isometropia is present.