The Clinical Application Of Free-flap LASEK In The Myopia Correction

Objective: Research on the free-flap LASEK to correct for myopia, and compared with standard LASEK. It is order to seek a new, safe, effective and good predictability of the surface treatment of myopia cutting surgical methods.Methods: Choose 80 examples of myopia patients (160 eyes), 38 examples men (76 eyes), 42 examples women (84 eyes), 18～32 years old , average age 23.5 years old, the average isoeffect sph, the standard LASEK group -5.20±1.25DS, the free-flap LASEK group -5.25±1.15DS, the average central corneal thickness of the standard LASEK group 482±15.25μm, and the free-flap LASEK group 485±14.20μm. Preoperative corneal topography: The standard LASEK group' SRI average to 0.33±0.29,SAI average to 0.34±0.31,SimK margin average to 0.58±0.85,SimK equivalent value average to 43.47±1.81;But the free-flap LASEK group' SRI average to 0.32±0.31,SAI average to 0.36±0.26,SimK margin average to 0.56±0.88,SimK equivalent value average to 43.60±1.78。Preoperative Wavefront aberration: The standard LASEK group' total wavefront aberration average to 5.038±3.111,higher-order aberrations average to 0.428±0.154;But the free-flap LASEK group' total wavefront aberration average to 5.036±3.124,higher-order aberrations average to 0.43±0.191。All patients were first performed a standard LASEK surgery, such as valve surgery in case of broken or free flap, then changed to the free-flap LASEK, the other eye continues to perform standard LASEK.1,3,7 days after the first review, after review 2w ~ 1m per 1, follow-up for 6 months. 1,3,7 days after follow-up observation of patients with major symptoms of the main feel, and after the resumption of the cornea, including: slit lamp observation of corneal epithelial repair, flap status and the early recovery of visual acuity. After 1 week, 3 weeks, 1 month, 3 month, 6-month follow-up visits to check visual acuity, refraction, slit lamp subepithelial corneal opacity (haze) situation, and corneal topography, central corneal thickness , intraocular pressure and wavefront aberration etc. Result: The pain of the 1th day postoperatively: free-flap LASEK group 1th grade for 34eyes(42.5%), 2th grade for 45eyes(56.3%), 3th grade for 1 eyes(1.2%); and standard LASEK group 1th grade for 21eyes(26.2%), 2th grade for 53eyes(66.3%), 3th grade for 6eyes(7.5%), inter-group difference is significant (P<0.05). The degree of conjunctival hyperemia: two groups of patients with varying degrees of conjunctival congestion to 1~2score, mainly two score were <2, P>0.05, the difference was not statistically significant. Corneal epithelial healing time: free-flap LASEK group average to 3.10 days, the standard LASEK group average to 3.68 days, the difference was statistically significant. Corneal flap state: standard LASEK group 65eyes(81.25%) take out contact lens as expected after 6d, 15eyes(18.75%) extension, the latest 11d; free-flap LASEK group of 76eyes(95.0%) 6d as expected in the postoperative take out contact lens, and another 4eyes(5.0%) extension, the latest 10d, in the corneal epithelium status and take out a mirror of time, the two groups were statistically significant differences (P<0.05) . Postoperative visual acuity and refractive state: three months ago, the 2 groups after surgery obtained uncorrected visual acuity and refraction numerical comparison there were significant differences (P<0.05), after 3 months the differences in uncorrected visual acuity and refraction the difference was not significant (P>0.05). Postoperative haze resulting situation: after 1,3 and 6 months, the free-flap LASEK group generated more than 0.5 grade haze is less than the standard LASEK group, the difference was significant (P<0.05 ). Corneal topography changes: postoperative corneal topography in June check mainly for the three kinds of shape, round or oval-shaped 120eyes(75.00%), kidney-shaped 34eyes(21.25%), semi-circular 6eyes(3.75%).we did not find partial center cutting or center island of the performance of topographic maps. After surgery, each group'SRI although fluctuations, but no significant change (P>0.05), SAI is a certain degree of change, after the period of operation and before, the difference was significant (P <0.05) .However, SRI and SAI after surgery between the two groups of comparison, the difference was significant (P<0.05). Each group stages after postoperative SimK margin compared with the preoperative, the difference was significant (P<0.05), after January, March and June between, there was no significant difference (P>0.05), SimK equivalent value decreased after the period compared with the preoperative, meaning the difference was significant (P<0.05), after postoperative the period between no significant difference (P>0.05), but after postoperative SimK difference between the two groups and SimK equivalent value, the difference was significant (P<0.05). Wavefront aberration change: two groups after postoperative the total wavefront aberration than preoperative reduction , the higher-order aberrations than preoperative increase .Over time, the postoperative group stages of numerical decline, but returned no preoperative levels after operation and before there was a significant difference (P<0.05); Preoperative between the two groups total wavefront aberration and higher-order aberrations is no difference, but after the period of postoperative the difference between the two groups there was a significant (P<0.05).Other post-operative complications: free-flap LASEK group less than the standard LASEK group.Conclusion: Free- flap LASEK correct for myopia than standard LASEK, in the post-operative visual acuity recovery, epithelial healing, eye pain relief, corneal topography and wavefront aberration in terms of better efficacy and stability, and security high, the forecast is good. Free- flap LASEK surgery without mechanical knife restrictions, operation simple. compared with the similar subepithelial excimer laser surgery it has non-corneal flap complications, postoperative complications related to lighter and higher visual quality. Free- flap LASEK surgeryconcept for laser subepithelial cutting to provide a new and more effective ways and broaden the scope of refractive surgery.So patients who have more choice of surgical procedures and it is a good supplement of myopic excimer laser surgery .