Effects of Illumination-Dependent Pupil Size on Higher Order Aberration

Purpose : We investigated the effect of illumination-dependent pupil size on higher order aberration. Methods : Thirty five patients (mean age, 22.5 ± 1.04 years) who had no ocular or systemic disease and had no other relevant surgical experience were selected, and we measured aberration. Due to the property of i.Profiler plus instrument, it is assumed that the pupil size ʻ3 mmʼ under photopic vision is similar to photopic vision environment and pupil size ʻmaximumʼ under semidark room is similar to mesopic vision environment. Correlation analysis between pupil size and equivalent defocus and equivalent blur circle was performed. Results : RMS values were 0.30±0.13 ㎛ and 0.38±0.15 ㎛ when the pupil size was divided into 3 mm and maximum. The equivalent defocus of total high order aberration was 0.28±0.14 D at the pupil size of 3 mm and 0.41±0.16 D at the maximum, which are significant differences(p=0.000). The difference of equivalent defocus of spherical aberration, coma aberration, and trefoil aberration was 0.07 D, 0.04 D, and 0.02 D at 3 mm and maximum, respectively, and there were significant differences in the spherical(p=0.000) and coma aberration(p=0.000)). There were significant positive correlations between equivalent defocus and equivalent blur circle(total higher order aberrations (R2=0.7045, p < 0.01), spherical aberration(R2=0.9376, p < 0.01), coma aberration(R2=0.8429, p < 0.01) and, trefoil aberration(R2=0.7824, p < 0.01)). Conclusions : The result of the aberration measurement is expressed as equivalent defocus, so that the degree of required correction can be expressed as diopter. Unless the correction of high order aberrations is considered, it is valuable to study the visual discomfort of high order aberrations as there would be a change in the corrected visual acuity.