abstract
- PURPOSE: To compare contrast sensitivity after phacoemulsification with implantation of the Tecnis intraocular lens (IOL) between patients with a selected preoperative corneal spherical aberration and patients without a selected amount of aberration. SETTING: Private practice, St. Catharines, Ontario, Canada. METHODS: Thirty-three cataract patients were divided into 2 groups. The first group (n = 13) included consecutive patients with a spherical aberration of at least +0.33 microm measured with the Oculus Easygraph. Consecutive patients meeting the inclusion criteria (n = 20) were included in the second group. All patients had phacoemulsification with implantation of the Tecnis IOL. After 3 to 5 weeks, contrast sensitivity was measured by sinusoidal grating charts for distance under photopic (85 cd/m2) and mesopic (3 cd/m2) conditions with optical correction in place. Five standard spatial frequencies were tested. RESULTS: All surgical procedures and postoperative courses were uneventful. The IOLs were in the bag without decentration or tilt. The mean preoperative spherical aberration was +0.370 microm +/- 0.024 (SD) in the first group and +0.291 +/- 0.081 microm in the second group (P = .0010). Patients in the first group had better contrast sensitivity than those in the second group. Statistically significant differences were detected at spatial frequencies of 6.0 cycles per degree (cpd) and 12 cpd under photopic conditions (P = .0267 and P = .0215, respectively) and mesopic conditions (P = .0356 and P = .0217, respectively). CONCLUSIONS: The Tecnis IOL has a negative spherical aberration of -0.27 microm. Targeting for a postoperative mean residual spherical aberration of approximately +0.10 microm by selecting patients according to their preoperative spherical aberration resulted in better contrast sensitivity.