Considering Spherical Aberration in Choosing the Wavefront Map for Laser Vision Correction

ABSTRACT

PURPOSE: To report the dynamic nature of human optical aberrations in the scotopic condition. METHODS: A total of 20 eyes who were candidates for laser vision correction were included in the present study. Repeated wavefront data were obtained using WavescanTM (AMO/VISX). From the wavefront analysis data, the sphere, astigmatism, average pupil size, spherical aberration, coma and trefoil were selected and used to investigate any correlation among the parameters. RESULTS: The sphere, spherical aberration, coma and pupil size showed a dynamic change in the scotopic condition. The spherical aberration and pupil size decreased by the amount of 0.10 +/- 0.04 microm and 0.55 +/- 0.37 mm as the sphere changed 1 D in myopic direction. There was significant positive correlation between the sphere and spherical aberration in 13 eyes of 9 patients (65%), between the sphere and pupil size in 5 eyes of 4 patients (25%), and between the sphere and coma in 3 eyes of 3 patients (15%). The spherical aberration decreased significantly in 4 eyes of 4 patients (20%) as the pupil size decreased. CONCLUSIONS: The optical aberration of human eyes showed a dynamic nature in the scotopic condition. In particular, there was significant correlation between the sphere and spherical aberration. The observed correlations have the potential to be used as helpful indicators to select the optimal wavefront data for the laser vision correction.