Objective and subjective outcomes in comparing three different aspheric intraocular lens implants with their spherical counterparts.

PURPOSE

To look for objective and subjective differences between three types of aspheric intraocular lens implants and their spherical counterparts.

METHODS

Thirty patients were randomised to receive one of six lens implants including three aspheric lenses and their spherical counterparts. Pre and postoperative testing was carried out including visual acuity, contrast sensitivity and wavefront analysis. All patients were asked to fill in a visual function questionnaire (modification of cataract TyPE) to assess subjective differences in visual quality.

RESULTS

There was no significant difference between groups for best-corrected visual acuity. Contrast sensitivity testing showed the Tecnis lens to perform better than the Cee-on Edge in all lighting conditions with significant differences at 3 and/or 6 cycles/degree in three out of four lighting conditions. No significant differences in contrast sensitivity were seen between the other lens pairs. All aspheric lenses showed less spherical aberration than their spherical pairs with statistical significance reached in two out of three pairs (the Ceeon Edge vs Tecnis, and Acrysof Natural vs IQ). The questionnaire revealed no evidence of improved subjective vision with the aspheric lenses compared to the spherical lenses.

CONCLUSIONS

This pilot study concurs with previously published trials in showing decreased spherical aberration and improved contrast sensitivity with aspheric lenses compared to spherical lenses. There was no evidence that the patients implanted with aspheric lenses rate their quality of vision higher than those implanted with spherical lenses. Study numbers were small and larger numbers may be required to demonstrate statistical differences in subjective data.