Association between amblyopia and higher-order aberrations.

We report a case with asymmetric higher-order aberrations and wavefront profiles possibly leading to unilateral amblyopia. Stimulus deprivation, strabismus, substantially unequal refractive error, microtropia, and organic causes were ruled out. Keratographic assessment was similar bilaterally, but there was a between-eye difference by wavefront analysis. The predominant aberration in the left eye was defocus and in the right eye, x-axis trefoil. This resulted in different wavefront profiles and point-spread functions, which could have caused amblyopia during the critical age period. The case shows a previously unreported but logically probable cause of amblyopia. Since a single case can suggest the biological plausibility of a hypothesis but cannot prove the strength of the association, further research is required in patients with no cause or an insufficient explanation for amblyopia, especially patients with a mild refractive error difference.