ABSTRACT
Background Femtosecond laser in situ keratomileusis (LASIK) inevitably injury keratocytes and corneal nerve fibers.The research report about postoperative morphological changes of corneal nerve regeneration and keratocytes in femtosecond LASIK is still rare.Objective The aim of this study was to observe the kinetic changes of keratocytes and corneal nerve in corneal flap after femtosecond LASIK.Method Femtosecond laser manufacture corneal flap of LASIK surgery was performed on 60 eyes of 30 patients with refractive error using both femtosecond laser system and excimer laser treatment system.The repair of corneal wound was examined by slit lamp microscope,and the morphology of keratocytes and corneal nerve were observed with confocal microscope 1 week,1month,3 months after surgery,respectively.Results No haze or flap folds were found under the slit lamp microscope from 1 week through 3 months after operation.One week after surgery,the corneal stromal cells at the interface of the corneal flap appeared to be a mild activation status in 42 eyes (70％),but the activated cells gradually reduced with lapse of time.Three months after surgery,mild activation state still was found in 7 eyes (12％).One week after surgery,independent,short (＜50 μm),curved subbasal nerve fibers were exhibited in 7 eyes (12％),and curved filamentous nerve fibers were discovered in 48 eyes (80％) one month after surgery.The nerve fiber length of subbasal nerve was ＞200 μm in 27 eyes (45％) and classes beaded structure appeared 3 months after operation but were still different with preoperative subbasal nerve fibers.One week after the operation,filaments or discontinuous nerve fibers could been seen in 46 eyes (77％) at theinterface,and long nerve fibers or filamentous nerves were visible around the terminal or periphery of nerve fibers in 49 eyes (82％) one month after surgery,and long nerve fibers or filaments of nerve fibers were visible in 57 eyes (95％) 3 months after the surgery.Conclusions Femtosecond LASIK cause wound reaction at cellular level.Corneal nerve fibers recover with the extension of time,but there are still some morphological differences 3 months after surgery from preoperation.