Therapeutic effect of three different patterns of laser <i>in situ</i> keratomileusis

AIM: To compare therapeutic effect of three different patterns of laser in situ keratomileusis: standard laser in situ keratomileusis(S-LASIK), aspheric ablation laser in situ keratomileusis(A-LASIK), and tissue-saving laser in situ keratomileusis(T-LASIK). METHODS: Retrospective Case Series. From February 2001 to October 2012, 66 patients(112 eyes), who received laser in situ keratomileusis in our hospital and were followed up for more than 6 months, were analyzed retrospectively. The surgery was underwent with 217z excimer laser of Bausch & Lomb and with the 110μm corneal flap made by OUP90 of Moria company. According to diopter, corneal thickness and pupil diameter in dark, different surgical patterns were adopted, and thus the patients were divided into three groups: S-LASIK(n=36), A-LASIK(n=40)and T-LASIK(n=36). The preoperative nocturnal visual satisfaction, nocturnal visual satisfaction in 6 months after the operation, UCVA, BSCVA, spherical equivalent(SE), K value measured by Orbscan II anterior eye segment analysis system, thinnest corneal thickness(TCT)and high-order aberration analysis(C7, C8, C12, RMSh)at 5mm pupil diameter were noted. Changes and relevance of these testing indexes were observed and analyzed preoperatively and postoperatively.RESULTS: According to the research on nocturnal visual satisfaction in 6 months after surgery, A-LASIK group showed better outcome than S-LASIK group and T-LASIK group. In the same period, SE less than ±0.5D in three groups accounted for 96.43%. RMSh, C7 and C12 in three groups all increased postoperatively(P2), 0.72±0.08μm/(D·mm2), 0.59±0.09μm/(D·mm2)respectively(PCONCLUSION: S-LASIK, A-LASIK and T-LASIK can correct myopia and astigmatism effectively. RMSh, C7 and C12 in three groups have all increased postoperatively. The nocturnal visual satisfaction of A-LASIK group is superior to the other two groups, which may be associated with the less change in aberration. Compared with S-LASIK, both A-LASIK and T-LASIK are effective in saving corneal tissue. Ensuring the effect of clinical correction, meanwhile, group T-LASIK reduced the corneal thickness correction to reduce the changes of corneal blomechanics as much as possible