Comparison of pseudophakic visual quality in spherical and aspherical intraocular lenses

Can J Ophthalmol 44(3):5 (2009) PMID 19491981

Objective: This study compares the visual performance of spherical and aspherical intraocular lenses (lOLs) by measuring higher-order aberration and contrast sensitivity (CS) values. Design: Prospective controlled study. Participants: Fifty-seven patients with age-related cataract (61 eyes). Methods: Patients were randomly allocated to 1 of 3 groups and implanted with either aspherical IOLs, Acrysof IQ (SN60WF) or Tecnis Z9001, or a spherical IOL, Acrysof Natural. Patients underwent routine examinations, including visual acuity, slit-lamp checks, and best-corrected visual acuity (BCVA), as well as measurement of higher-order aberrations and CS values, preoperatively and at 1 week, 1 month, and 2 months postoperatively. Results: All the patients had a BCVA better than 20/30 postoperatively. The spherical aberrations of the IQ group and Tecnis group were both lower than in the Natural (control) group (IQ: p < 0.05); there was no significant difference in coma and higher-order aberration. No statistically significant difference was found in spherical aberration, coma, or higher-order aberration between the IQ and Tecnis groups. Under glare conditions, the CS values of the 2 aspherical IOLs were obviously better (IQ: p < 0.05; Tecnis: p < 0.05) than the CS value of the spherical IOL group at low frequency (IQ: 6.3^o, Tecnis: 4.0^o); under non-glare conditions there was a significant difference in CS values between the aspherical IOL groups and the control group (IQ: p < 0.01) at low frequency (both 6.3^o). There was no statistical difference between the IQ and the Tecnis groups with or without glare. Conclusions: An aspherical IOL can effectively reduce spherical aberration after cataract surgery, enhance CS values, and improve visual quality compared with traditional spherical IOLs for age-related cataract. However, there was no statistically significant difference in postoperative aberration and CS values between the Acrysof IQ and Tecnis Z9001 aspherical IOLs.