Conservation of corneal tissue with wavefront-guided laser in situ keratomileusis

To determine whether corneal tissue can be conserved with wavefront-guided ablation compared to conventional surgery with a larger ablation zone for attempted prevention of glare and halo.

Department of Ophthalmology, Ilsan Paik Hospital, Inje University, Korea.

This prospective study was composed of 2 parts: First, 40 eyes of 20 patients were studied to determine whether a larger optical ablation could be beneficial in prevention of glare after conventional laser in situ keratomileusis (LASIK) surgery. One eye in each patient was treated with a 6.00 mm optical zone, and the other with a 6.25 mm optical zone. Second, 20 eyes of 10 patients with a higher-order root mean square (RMS) value of 0.3 or greater were evaluated to learn whether a wavefront-guided ablation could be as effective as a larger conventional optical ablation. One eye in each patient was treated by conventional LASIK surgery with a 6.25 mm optical zone, and the other eye was treated by wavefront-guided LASIK surgery with a 6.00 mm optical zone. All patients were analyzed with a WASCA analyzer (Carl Zeiss Meditec) preoperatively, and 1 month and 3 months after surgery.

Higher-order aberrations including coma, spherical aberration, and higher-order RMS were statistically significantly increased after conventional surgery with both a 6.00 mm and 6.25 mm optical zone. High-order aberrations including comaer- and spherical aberration after conventional surgery with 6.25 mm zone were statistically significantly increased. However, coma and higher-order RMS did not show a statistically significant increase between pre-LASIK and post-LASIK in wavefront-ablated eyes with a 6.00 mm optical zone.

Wavefront ablation showed less increase of coma and higher-order RMS regardless of a smaller optical zone. This finding might provide a clinical clue for an advantage of wavefront-guided ablation from the standpoint of corneal tissue conservation.