Comparison of contrast sensitivity in eyes with toric and aspheric intraocular lenses

INTRODUCTION: Study aimed to compare Visual Acuity, ocular Spherical Aberration (SA) and Contrast Sensitivity (CS) in eyes implanted with the AcrySof toric IOL and AcrySof Natural IQ. METHODS: Fifty-eight eyes of 46 patients participated in this prospective randomized study. After phacoemulsification the eyes received the AcrySof toric or AcrySof IQ IOLs depending on their preoperative corneal astigmatism. Three month after surgery, all patients underwent complete ophthalmological examination including corneal topography, best corrected visual acuity, wavefront analysis for 6 mm pupil diameter and CS measurements with the CSV-1000HGT test under photopic (85 cd/m2) and mesopic conditions (5 cd/m2). RESULTS: BCVA in toric group was 0.054±0.043 logMAR and 0.030±0.037 logMAR in aspheric group (all patients achieved a BCVA of 20/25 or better). The mean postoperative SA was higher in the AcrySof toric group than the AcrySof IQ group (0.540±0.887 vs. 0.216±0.047 µm) and this difference was statistically significant (p<0.001). CS results showed no statistically significant differences between the values post-implantation at any lighting condition and spatial frequency (p>0.01). The AcrySof toric lens provided excellent rotational stability in the capsular bag with an average lens rotation of less than 3.3±2.5 degrees. CONCLUSIONS: The AcrySof toric IOL and aspheric AcrySof IQ yield similar and good visual outcomes. However, the AcrySof IQ IOL reduced significantly the SA for large pupils in relation to toric IOL. Surgeons should consider that patients may benefit from aspheric designs. Future studies, should consider direct comparison between spherical and aspheric toric IOLs to analyze properly the benefit in visual performance