Vector Analysis of Cross Cylinder LASIK With the NIDEK EC-5000 Excimer Laser for High Astigmatism

PURPOSE: To evaluate visual outcomes of LASIK in eyes with high astigmatic refractive errors with low spherical component. METHODS: We prospectively evaluated cross cylinder LASIK in patients with high astigmatic eyes with low spherical component over a 2-year period. All laser surgeries were performed with the NIDEK EC-5000 excimer laser. We used power vectors (M [spherical equivalent] and J(0) and J(4). [cylinder]) to analyze the astigmatic reo Main outcome measures were uncorrected visual sults. acuity (UCVA), best spectacle-corrected visual acuity (BSCVA), manifest refraction, and complications. RESULTS: Thirty-four eyes of 22 patients were included Patients were followed for 21.8 +/- 3.7 months. At the last examination, UCVA of 20/40 or better was observed in 33 (97.1%) eyes. Best spectacle-corrected visual acuity after LASIK improved significantly in comparison to BSCVA before surgery (P<.005). Mean preoperative cylinder was -4.73 +/- 0.89 diopters (D) (range: -4.00 to -7.00 D), which decreased to -0.29 +/- 0.47 D (range: 0.00 to -1.50 D) at last follow-up (P<.001). Reduction in the magnitude of power vectors was 92.4% for M, 103.2% for J(0), and 76.4% for J(45). No cases of postoperative astigmatic regression or corneal haze were observed. CONCLUSIONS Cross cylinder LASIK with the NIDEK EC-5000 excimer laser is a successful procedure for correcting high astigmatism and improving vision. [J Refract Surg. 2009;25:1075-1082.] doi:10.3928/1081597X-20091117-06