Purpose: To evaluate the efficacy, predictability, and safety of bitoric laser in situ keratomileusis (LASIK) for the correction of mixed astigmatism.
Setting: Instituto Oftalmológico de Alicante, Alicante, Spain.
Methods: This prospective study included 28 eyes of 21 patients with mixed astigmatism who had bitoric LASIK using the Hansatome microkeratome (Bausch & Lomb Surgical) and the Chiron Technolas 217 excimer laser (Bausch & Lomb Surgical). The main outcome measures were uncorrected visual acuity (UCVA), best corrected visual acuity (BCVA), defocus equivalent, blur strength, and refraction.
Results: Six months after bitoric LASIK, the mean UCVA was 0.70 +/- 0.23 (SD). The percentage of eyes with a UCVA of 20/40 or better was 78.6% and of 20/20, 21.4%. There was a statistically significant increase in the mean BCVA from 0.71 +/- 0.19 before surgery to 0.83 +/- 0.15 at 6 months (P =.0004). Three eyes (10.7%) lost 1 line of BCVA; 19 eyes (67.9%) gained 1 or more lines. The mean preoperative astigmatism of -4.04 +/- 1.13 diopters (D) was reduced to -0.67 +/- 0.79 D after surgery. The defocus equivalent was less than 1.00 D in 75.0% of eyes and less than 0.50 D in 64.3%. Vector analysis showed that the mean achieved correction was 97.4% of the intended correction.
Conclusions: Bitoric LASIK was a safe, effective, and predictable procedure in the treatment of mixed astigmatism. It is a means to improving BCVA in a significant percentage of patients.