IOLs both provide good results in head-to-head comparison

IOL preference could be related to the degree of dysphotopsia, a better depth of field, or other factors.

However, twice as many patients preferred the Akreos IOL compared with the Tecnis IOL. Dysphotopsias cause fewer problems in eyes with the Akreos IOL than in eyes with the Tecnis IOL. Maximal neutralization of higher-order aberrations did not prove to be necessary for good quality of vision.

"The visual acuity results did not differ significantly between the two IOLs with the high-contrast ETDRS chart or the low-contrast ETDRS chart. The photopic and mesopic contrast sensitivity functions were strikingly similar for the IOLs for any of the spatial frequencies," Dr. Johansson reported.

"There were slightly more higher-order aberrations in the eyes with the Akreos IOLs implanted compared with the eyes with the Tecnis IOLs implanted, which was expected. This is mainly due to the residual corneal spherical aberration." he said.

Dr. Johansson demonstrated the corneal spherical aberration for pupil diameters of 4, 4.5, and 5 mm.

"The residual spherical aberration in the eye provides a potentially useful depth of field. The results indicate a significantly larger depth of field for the Akreos IOL, indicating the level of pseudoaccommodation," he commented.

The patient questionnaire contained questions about dysphotopic symptoms and to what extent the symptoms disturbed their vision during their activities of daily living and under certain lighting conditions. The patients who reported dysphotopic symptoms were asked which eye had more symptoms.