The Clinical Effect Of Wavefront Guided Excimer Laser Ablation Combined With Iris Registration For Treatment Of Low To Moderate Myopia Astigmatism

Objective:To compare the clinical results between iris registration combined with wavefront aberration guided laser subepithelial keratomileusis (LASEK), iris registration combined with wavefront aberration guided laser in situ keratomileusis (LASIK)and conventional LASIK in the treatment of low to moderate myopia astigmatism, the reseach can provide more instructions for refractive surgeons to choose more appropriate operation.Methods:Iris registration combined with wavefront aberrtion guided LASEK was performed in 15 patients (29 eyes) as clinical group A, and iris registration combined with wavefront aberrtion guided LASIK was performed in 16 patients (32 eyes) as clinical groupB, and conventional LASIK was performed in 16 patients(30 eyes) as control groupC. During the surgery, we measured the pupil centroil shift and eye cyclotorision. After the surgery we compared the clinical results of the three groups.1. The cyclotorsion during surgery was detected in groupA and groupB. The mean rotation angle was (3.85±2.02)°and the mean pupil centric shift was (0.23±0.18)mm in the X axis and (0.18±0.13)mm in the Y axis respectively.2. Uncorrected visual acuity(UCVA) in all groups was 0.8 or better at 1 month postoperatively. UCVA of 62% in groupA,60% in groupB,33% in control group was better than preoperative best corrected visual acuity(BSCVA). There was no significant difference between groupA and groupB postoperatively (P>0.05),but there was significant difference between clinical groups and control group(P<0.05). There was no significant difference in myopia between three groups at 1,3,6 months postoperatively (P>0.05). The degree of astigmatism in the groupC(-0.47±0.17)D at 6 month after the operation was signigicantly higher than that in the groupA(-0.20±0.11)D and groupB(-0.22±0.12)D (P<0.05).3. The root means squares of total higher order aberration (HOA) increased at 1 month,3 month,6 month postoperately. The amount of increase in HOA was 78% in groupB, which was lower than 90% in groupA and 120% in groupC at 1 month. But at 6 month the amount of increase in HO A was 71% in groupA, there was lower than 85% in groupB and 115% in groupC, there was significant difference between clinical group and control groups(P<0.05).4. The root mean square of spherical aberration (SA) and coma increased at 1 month,3 month,6 month postoperately. The amount of increase in SA respectively was 130% in groupA,146% in groupB and 180% in groupC, there was significant difference between clinical groups and control group(P<0.05). The amount of increase in coma was 159% in groupC, which was significantly higher than 77% in groupA and 80% in groupB(P<0.05).Conclusion:Wavefront guided LASEK or LASIK with iris registration are more effective for the low to moderate myopia astigmatism than the conventional LASIK. In the treatment of the low to moderate myopia astigmatism, LASEK is more safe and reliable than LASIK.