Customized photorefractive keratectomy for the correction of regular and irregular astigmatism after penetrating keratoplasty.

PURPOSE: To report visual, wavefront, and topographic outcomes in 5 post-penetrating keratoplasty patients who underwent customized aspheric topography-guided photorefractive keratectomy for high astigmatism or severe higher-order aberrations.

METHODS

A chart review was performed for data collection. The custom aspheric transition zone ablation algorithm (CATz) with the CX III excimer was used for all treatments. Ablations were calculated based on corneal elevation data. Phototherapeutic keratectomy was the first step of the procedure. Visual acuity, corneal higher-order wavefront aberrations (Zernike sixth order and 4-mm diameter), corneal topography, and patient satisfaction were evaluated preoperatively and at the last visit postoperatively (range, 3 months to 4.5 years). The paired t test was used for statistical comparison of higher-order aberrations, with P < 0.05 indicating statistical significance.

RESULTS

The mean spherical equivalent was -4.50 diopters (D) (range, -9.50 to +3.25 D) preoperatively and -1.00 D (range, -3.25 to +0.25 D) at the final visit. The mean cylinder was -7.00 D (range, -4.75 to -9.00 D) preoperatively and -1.25 D (range, -0.50 to -2.50 D) postoperatively. Postoperative uncorrected distance visual acuity increased in all eyes. No eyes lost corrected distance visual acuity postoperatively. There was a statistically significant decrease in higher-order corneal spherical aberration postoperatively (P = 0.02). Four patients were "very satisfied" or "satisfied" with the postoperative outcome, and 1 patient was "somewhat satisfied". All patients reported reduced symptoms postoperatively.

CONCLUSIONS

Phototherapeutic keratectomy with CATz was effective as a single-step treatment for severe higher-order aberrations or moderate astigmatism after penetrating keratoplasty.