Relationship between Higher Order Aberrations and Astigmatism in Hyperopic Amblyopia

Abstract

Aim. To study the dynamics of changes in the values of higher order aberrations in amblyopia treatment and the correlation between higher-order aberrations and astigmatism in patients with hyperopic amblyopia.Methods. This cohort prospective study included 36 patients (36 eyes) with refractive amblyopia aged 4 to 16 years. All patients had anisometropia: emmetropia in one eye and hyperopic astigmatism combined with refractive amblyopia of varying degrees in the other eye. Patients were divided into two groups depending on the degree of astigmatism. Astigmatism greater than 1.5 D was detected in 20 patients (55.5%) and astigmatism less than 1.5 D was detected in 16 patients (44.5%). All patients underwent a complex treatment, including twenty half-hour sessions of videocomputer autotraining using “Amblyotron” device during 20 days, in addition to constant wearing of glasses. Higher order aberrations were measured using the WaveScan Wavefront System aberrometer at the first visit and at 3-, 6 - and 12-month follow-up. A correlation analysis was performed to assess the relationship between higher order aberrations and astigmatism.Results. There was a statistically significant difference in treatment success between groups with high and low astigmatism. In both groups, higher order aberrations were reduced during the treatment of amblyopia. When comparing the two groups, a significant difference in coma was found at 12-month follow-up (p = 0.043). At 12-month follow-up, coma showed a statistically significant correlation with astigmatism, and a stronger correlation with astigmatism was found in the group of patients with high astigmatism.Conclusions. In patients with refractive amblyopia associated with astigmatism, the decrease in visual acuity is directly dependent on the values of higher-order aberrations, especially on the values of coma, which should be considered as the cause of the development of amblyopia.