Objective Measurement of Optical Aberrations in Myopic Eyes

To determine whether the degree of myopia affects the optical quality of the retinal image after appropriate correction, monochromatic aberrations of the human eye were measured as a function of the degree of myopia.Using a modified Hartmann-Shack method, a population of 27 myopic (up to -9.25 D) and 7 emmetropic optometry students (18-32 years) were objectively evaluated before and after pupil dilation. We then identified for each subject the most influential aberration types, and we calculated the profile of wavefront aberration. To study the behavior of aberration as a function of the degree of myopia, we determined the maximum value of aberration as well as the root mean square (rms) value.It turned out that aberration increases with the refractive error in a quasi-linear relationship for pupil diameters of 5 and 9 mm. This result is valid for both rms and maximum values.We objectively showed that optical quality decreases as myopia increases and as the pupil gets larger. Coma is more frequent in high myopia, and spherical aberration occurs more frequently for dilated pupils.