Higher Order Ocular Aberrations in Eyes with Myopia and Myopic Astigmatism

Objective To analyze the characteristics of higher order ocular aberrations in eyes with myopia and myopic astigmatism, and determine the effects of myopia and astigmatism on higher order aberrations. Methods One hundred and sixty one myopic astigmatism eyes were evaluated before refractive surgery by using a Hartmann-Shack method. According to the degree of myopia and astigmatism, it is divided into high myopia, moderate myopia, low myopia and groups Ⅰ and Ⅱ. The values of higher-order aberrations for each subject with pupil diameters of 4.0, 5.0 or 6.0 mm were calculated . The correlations between higher order aberrations and myopia, astigmatism, and best corrective vision acuity (BSCVA), respectively, were analyzed using analysis of variance and linear regression method. Results All types of higher order aberrations were increased significantly with increasing pupil size. However, they were not affected by the degree of myopia. In 5.0 mm and 6.0 mm pupil, astigmatism affected total higher order aberrations and vertical primary coma, but horizontal primary coma and spherical aberration. In 5.0 mm and 6.0 mm pupil, there was a positive relationship between vertical primary coma and BSCVA (r=0.542, 0.685, P0.05), a negative relationship between spherical aberration and BSCVA(r=-0.573, -0.758,P0.05). Conclusions All types of higher order aberrations are affected by pupil diameters, but not the degree of myopia. Astigmatism affects total higher order aberrations and vertical primary coma. Maintaining smaller vertical primary coma aberration and correcting spherical aberration completely for myopia and myopic astigmatism may be the best choice for customized cornea laser ablation surgery.