Abstract
Purpose: :
Femtosecond (fs) technology enables to create a tissue-friendly flap by LASIK. The aim of this study is to compare the regeneration of subepithelial nerve plexus (SEP) and corneal sensation based on 2 different femtosecond methods.
Methods: :
18 eyes from 9 Patients aged 17-43 were investigated with the Heidelberg Retina Tomograph combined with Rostock Cornea Module 1 week as well as 1, 3 and 6 months after the fs-LASIK. Surgeries were performed on both eyes: one eye underwent the FLEx method (Femtosecond Lenticule Extraction) with overhead hinge (90º). The other eye was operated with 2 fs-incisions (90º each) on the temporal and nasal side (SMILE method- Small Incision Lenticule Extraction). Confocal microscopy of SEP was performed as follows: (i) FLEx group: in center of flap, on flap edge (temporal, at bottom and nasal) and in hinge area; (ii) SMILE group: on flap edge (temporal and nasal), in intact overhead and bottom areas. Off-line as well as on-line (3 and 6 months post-op) 2D-Mapping of SEP was performed. Corneal sensation was followed up with Cochet-Bonnet esthesiometer.
Results: :
In vivo confocal microscopy and following reconstruction allow mapping up to 2.0 mm x 2.0 mm in off-line and up to 3.2 mm x 3.2 mm in on-line mode. Moreover, the reconstruction of the flap edge is possible. The SEP ramifications of hinge area run up to corneal center after FLEx. SMILE method is characterized by intact structure of SEP in center, the SEP ramifications run continuously in vertical direction. First ramifications regenerated over flap edge were noted after 1 month. The regeneration of SEP correlates with esthesiometry. Qualitative analysis of SEP showed a better regeneration of SEP in SMILE group.
Conclusions: :
Corneal sensation correlates with regeneration of SEP after fs-LASIK. SMILE method showed a better regeneration of SEP.
Clinical Trial: :
Ethics Cmt Thuringia State Med Bd, Jena, Germany
Keywords: cornea: clinical science • refractive surgery: LASIK • regeneration