Abstract
Abstract: :
Purpose: To determine the difference in visual acuity, refractive outcomes and wavefront error between patients undergoing conventional (Group 1) or wavefront–guided (WG)(Group 2) LASIK for myopic astigmatism. Methods: Twenty four eyes of twelve patients were randomised to receive either conventional (preoperative MRSE –4.86 ± 0.29D)(mean ± SEM) or WG LASIK (preoperative MRSE –5.08 ± 0.23D) using the VisX Star S4 laser employing v3.1 software. All patients underwent a complete ophthalmic examination with measurement of Snellen and logMAR acuity, Pelli–Robson score (PR), manifest refraction and corneal topography (Orbscan, Bausch and Lomb). A Shack–Hartmann aberrometer (Wavescan, VisX) was used to determine the wavefront error. Following treatment, patients were examined at 1, 3 and 12 months. Results: There was no statistical difference in preoperative characteristics between the groups. At three months post–operatively all eyes achieved an uncorrected visual acuity of 20/20 or better with no loss of lines of best–corrected acuity or significant difference in logMAR or PR scores. The MRSE for Group 1 (–0.28 ± 0.06D) was, however, significantly lower than for Group 2 (–0.55 ± 0.10D)(p<0.5). At three months follow up, total RMS error (0.328 ± 0.03µm group 1 vs. 0.308 ± 0.03µm group 2), vertical and horizontal coma, trephoil 30o and spherical aberration was not significantly different between groups. Conclusions: In this pilot study, wavefront–guided LASIKoffered no significant advantage in visual performance over LASIKemploying a standard treatment algorithm but did result in a significantly higher MRSE at 3 month follow up.
Keywords: laser • refractive surgery: comparative studies • refractive surgery: LASIK