Index of contrast sensitivity (ICS) in pseudophakic eyes with different intraocular lens designs.

PURPOSE: To evaluate the index of contrast sensitivity (ICS) in eyes after cataract surgery with various intraocular lens designs and to compare with the area under log contrast sensitivity curve (AULCSF).

METHODS

The study comprised 395 eyes of 198 patients in the age of 73.1 ± 7.86 years receiving 11 different aspheric IOL designs (aberration-free and correcting) and a spherical (IOL) as control group. Follow-up examination after bilateral cataract surgery was completed within 71 ± 21.4 days after second IOL implantation. Patients underwent complete examination and biometry before surgery. The follow-up examination included visual acuity, pupil diameter, residual spherical aberration and mesopic as well as photopic contrast sensitivity (CS) measured with the Optec 6500 Functional Vision Analyzer. From the contrast sensitivity, we calculated the ICS according to Haughom and Strand.

RESULTS

The median mesopic ICS was -144, -131 and -85, and the median photopic ICS was -289, -285 and -212 for the spherical, aberration-free and aberration-correcting IOL group, respectively. While we could not detect a significant difference between the aberration groups in some spatial frequencies, the ICS showed a significant difference between the aberration-correcting and the aberration-free or the spherical group, respectively. No significant difference was found between the aberration-free and the spherical group.

CONCLUSIONS

The ICS is a useful index for evaluation of overall CS and comparison of different patient groups. With aberration-correcting IOLs, ICS was statistically better than with aberration-free or spherical IOLs, whereas the latter two showed no significant difference.