The Character Of Corneal Regeneration Nerves After Different Excimer Laser Operation By Confocal Microscopy

Purpose: To compare the regeneration of corneal subbasal nerve fiber bundles(NFBs) after laser in situ kerotomileusis(LASIK) and both-sides LASIK (BSL), and to provide objective proof for rationalized clinical operation.Methods: 22 eyes received LASIK to correct a mean refractive error of -5.26±-0.72 diopters,and 16 eyes received BSL to correct a mean refractive error of -6.85±-0.83 diopters. The corneal thickness before operation is 544±28μm in LASIK and 518±29μm in BSL.The ablation depth of operation is 93.7±12.4μm in LASIK and 109.1±11μm(including 74.4±12.7μm on the corneal flap) in BSL, The corneal thickness after operation is:449.4±22.8μm in LASIK and 408.5±24.7μm in BSL. Corneas were examined by confocal microscopy at 1 day, 1 weeks, 1 months, 3months and 6 months after the operation ,and subbasal nerve fibre bundles were measured to determine the length. difference were compared by Pearson Chi-Square test.Results:By confocal microscopy, The central area of the cornea after operation showed long degenerating NFBs existing with short ,unconnected nerve fibres at 1day and mainly short(<50μm),unconnected subbasal nerve fibres or no image at 1 weeks in two groups.At the subsequently times, The central area of the cornea showed more and more long,interconnected NFBs.After LASIK,the ratio of subbasal NFBs >200μm was respectively 36.3%,36.4%,63.6% at 1 months,3months,6months, and after BSL,the ratio was respectively 12.5%,25%, 68.8%. At every time,there were not significantly different(1 months:p=0.251,3 months:p=0.216,6 months:0.764) in regeneration of subbasal NFBs between two groups.Conclusions: There were significantly different in mean refractive,corneal thickness before and after operation ,and ablation depth et al. between LASIK and BSL,But there were not significantly different in length and morphology of corneal subbasal NFBs between LASIK and BSL at every time point of post-operation.