cross cylinder ablation in lasik for high astigmatism

purpose: to evaluate the visual outcomes of cross-cylinder ablation in laser in situ keratomileusis (lasik) for eyes with high astigmatic refractive errors and low spherical component. methods: we prospectively evaluated cross cylinder lasik in patients with high astigmatic refractive error but low spherical component over a period of 2 years. all procedures were performed with the nidek ec-5000 excimer laser. main outcome measures included uncorrected visual 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± 3.6 months. at the last examination, ucva of 20/40 or better was observed in 33 eyes (97.1%).  bscva after lasik improved significantly in comparison to bscva before surgery (p<0.005). the mean preoperative cylinder was -4.73±0.89d (-4.00 to -7.00 d) which was reduced to -0.29±0.47 d (0.00 to -1.50 d) at the last follow up visit (p<0.001). no cases of postoperative astigmatic regression or corneal haze were observed. conclusion: cross cylinder lasik with the nidek ec-5000 is a successful procedure for correction of high astigmatism. it seems to be clinically safe, effective and predictable.