Abstract:

Objective To compare the visual effects of laser in situ keratomileusis (LASIK) for myopia with different ablation centers. Methods The clinical data of patients with myopia undergoing LASIK were collected. Among 190 patients (380 eyes), 90 patients (180 eyes) were treated with visual axis corneal reflex point (VACRP) as ablation center (VACRP group), and the other 100 patients (200 eyes) were treated with pupil center (PC) as ablation center (PC group). All patients were reexamined one month after operation, the vision-related parameters were measured, and the visual acuity, safety index, efficacy index, refraction, ablation center deviation, corneal higher order aberration and contrast sensitivity were compared between two groups. Results One month after operation, there was no significant difference in uncorrected visual acuity, best spectacle-corrected visual acuity (BSCVA), manifest refraction spherical equivalent (MRSE), safety index and efficacy index between VACRP group and PC group (P>0.05). BSCVA and safety index in patients with preoperative visual acuity >－6.00 D in VACRP group were significantly higher than those in patients with preoperative visual acuity >－6.00 D in PC group (P<0.01). The ablation center deviation in VACRP group was significantly shorter than that in PC group [(0.25±0.11) mm vs (0.51±0.19) mm, P<0.01]. The corneal high order aberration and coma in VACRP group were significantly lower than those in PC group (P<0.01). Postoperative contrast sensitivity visual acuity in VACRP group was significantly better than that in PC group on 18c/d spatial frequency with 85 cd/m2 intensity (P<0.01). Conclusion Compared with LASIK with PC as ablation center, LASIK with VACRP as ablation center may achieve better visual acuity, lower higher order aberrations and better contrast sensitivity in treatment of myopia.

Key words: keratomileusis, laser in situ, ablation center, visual axis corneal reflex point, pupil center