Comparative study of the high order aberrations between implantations of aspherical and spherical intraocular lens with normal pupil diameter

Abstract

Objective To compare the high order aberrations between implantations of aspherical and spherical intraocular lens with normal pupil diameter, calculate and analyze the differences in spherical aberration between the eyes implanted with aspherical and spherical intraocular lens in order to assess the visual quality and investigate the clinical results. Methods Fifty patients(66 eyes)with cataract underwent surgery from Jan 2010 to Apr 2010, and were divided into 2 groups randomly. Group 1: unifocal and aspherical intraocular lens(negative aberration KS-AIN), Group2: unifocal and spherical intraocular lens(KS-X). Sixty-six eyes were included in this study. The aberrations at normal pupil diameter(interval 3mm-5mm)were measured with the i-Trace wavefront aberrometer. Modulation transfer functions were collected at 3mm and 5mm pupil size. Independent-Samples t Test was used to analyze the data. Results No post-operative complication occurred in each group. The average uncorrected visual acuity(UCVA)was ≥ 0.5, and the average best corrected visual acuity(BCVA)was ≥ 0.6. With normal pupil diameter(mean 3.73± 0.49mm), aspheric IOL group showed less spherical aberration than spherical IOL group with statistical significance(P =0.0040.05, t =-3.216), the difference value(D-value)of spherical aberration was 0.069± 0.026?m. Also aspheric IOL group showed less aberration than spherical IOL group in total higher-order root-mean-square(total HOA RMS)values, but with no statistical difference(P >0.05). There were no significant differences in coma and trefoil values between each group(P >0.05). With 3mm pupil diameter, aspheric IOL group provided a statistically better contrast sensitivity only in 5 cycle/degree while a statistically better contrast sensitivity in all spatial frequencies with 5mm pupil diameter. Conclusions The aspheric lens provides the patients better quality of vision at normal pupil size compared to spherical lens because of the decreased spherical aberration and a better contrast sensitivity in part frequencies. However, aspheric lens cannot express its superiority in decreasing total HOA RMS with normal pupil diameter. Key words: Aspheric lens ; IOL ; iTrace ; Wavefront aberration ; Normal pupil diameter ;