Objective To investigate the effect of nerve growth factor (NGF) eye drops on central corneal nerve regeneration in rabbits after laser in situ keratomileusis (LASIK). Methods This was a experimental study. Fifteen New Zealand white rabbits were randomly assigned to one of three groups: NGF-treatment group, artificial tears hycosan-treatment group (positive control group), and normal saline-treatment group (negative control group) with five rabbits in each group, one drop every time and three times per day. The nerve density and the number of central corneal sub-basal and stromal cells were measured by confocal microscopy and were compared before surgery and at 1 week, 1 month, and 3 months after surgery.Analysis of variance was used for comparing the differences at different time points and among the three groups. Results The respective preoperative sub-basal nerve densities (SNDs) in the negative control group, positive control group, and NGF treatment group were 10 801±3 331 µm/mm2, 11 619±3 932 µm/mm2, and 12 299±2 622 µm/mm2. The number of corneal sub-basal nerve fibers were 12.2±3.4, 11.6±2.7, and 13.1±2.7 in the respective groups. In the preoperative corneas, the corneal stromal nerve densities were 7 258±1 242 µm/mm2, 8 148±2 462 µm/mm2, 8 984±1 526 µm/mm2, and the number of corneal stromal nerve fibers were 8.5±1.4, 8.9±2.6, 10.1±2.1 in the respective groups. Compared with preoperative values, nerve parameters in all groups increased at 1 week postoperatively (P<0.01). Compared with 1 week postoperative, SNDs and corneal stromal nerve densities in the NGF group increased at 1 month, while the control groups increased at 3 months (P<0.01). The number of sub-basal corneal nerve fibers in all three groups increased at 3 months (P<0.05). The number of corneal stromal nerve fibers increased at 1 month compared with 1 week postoperative in the NGF group and the positive control group (P<0.05). However there were no significant changes in the number of corneal stromal nerve fibers between pre- and postoperative 1 and 3 months measurements. Conclusion NGF eye drops promote corneal nerve repair at different periods following LASIK in rabbit eyes.
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