Clinical comparison of the optical performance of aspheric and spherical intraocular lenses.

PURPOSE

To compare the optical performance of aspheric Tecnis ZA9003 and spherical Sensar AR40e intraocular lenses (IOLs).

SETTING

Laboratory of Experimental Ophthalmology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands.

METHODS

An aspheric IOL was implanted in 1 eye and a spherical IOL in the other eye of patients with bilateral age-related cataract. Contrast sensitivity was measured using 2 computerized tests (vertical sine-modulated gratings and circular sine-modulated patterns) with cycloplegia and a 5.0 mm artificial pupil under photopic conditions at optimum refractive correction and at several defocus levels. The depth of focus and the myopic shift (shift of optimum focus toward more myopic values at lower spatial frequencies) were determined. Higher-order aberrations were assessed using a Hartmann-Shack wavefront analyzer; straylight was measured with a straylight meter.

RESULTS

In the 60 eyes evaluated, there were no statistically significant differences in contrast sensitivity measured at optimum focus, depth of focus, or straylight between the 2 IOLs. The mean spherical aberration was significantly lower with the aspheric IOL (-0.036 microm) than with the spherical IOL (0.064 microm) (P<.001) and the mean myopic shift, statistically significantly smaller (0.05 diopter [D] and -0.47 D, respectively) (P<.001).

CONCLUSIONS

Eyes with the aspheric IOL had lower spherical aberration than eyes with the spherical IOL and, related to that, a smaller myopic shift. No significant differences were found between the 2 IOLs in contrast sensitivity measured at optimum focus, depth of focus, or straylight.

FINANCIAL DISCLOSURE

No author has a financial or proprietary interest in any material or method mentioned.