Aim To evaluate and compare early corneal wound healing and inflammatory responses after small incision lenticule extraction (SMILE) versus femtosecond laser laser in situ keratomileusis (LASIK). Methods Thirty-six eyes of 36 rabbits underwent SMILE, while another 36 eyes of 36 rabbits were treated with femtosecond laser LASIK. All the eyes were subjected to the same refractive correction of −6.00 DS/−1.00 DC. Twelve eyes that had no surgery were included for control. After euthanisation, corneal tissue sections were evaluated with terminal deoxyribonucleotidyl transferase-mediated dUTP-digoxigenin nick-end labelling (TUNEL) assay to detect apoptosis at postoperative 4 and 24 h, immunocytochemistry for Ki67 to detect keratocyte proliferation at postoperative day 3, week 1 and month 1, and immunocytochemistry for CD11b to detect inflammation at postoperative day 1, day 3 and week 1, respectively. Results No adverse effects were noted after SMILE or LASIK. Corneal healing postoperatively was uneventful in all cases. There were significantly fewer TUNEL-positive corneal stromal cells after the SMILE procedure at 4 and 24 h postoperatively (p<0.01) compared with the LASIK procedure. In addition, immunocytochemistry showed significantly fewer Ki67-positive cells in the SMILE group than those in the femtosecond laser LASIK group at day 3 and week 1 postoperatively (p<0.05), but there was little expression of Ki67 at month 1 postoperatively in both groups. The CD11b-positive cells were significantly fewer in the SMILE group at day 1, day 3 and week 1 postoperatively (p<0.01). Conclusions SMILE induces less keratocyte apoptosis, proliferation and inflammation compared with femtosecond laser LASIK.

Large pupil diameters facilitate the effect of OK to slow axial growth in myopia. We speculate that this is because of enhancement of the myopic shift in the peripheral retina.

PurposeTo evaluate corneal reinnervation, and the corresponding corneal sensitivity and keratocyte density after small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK).MethodsIn this prospective, non-randomized observational study, 18 patients (32 eyes) received SMILE surgery, and 22 patients (42 eyes) received FS-LASIK surgery to correct myopia. The corneal subbasal nerve density and microscopic morphological changes in corneal architecture were evaluated by confocal microscopy prior to surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. A correlation analysis was performed between subbasal corneal nerve density and the corresponding keratocyte density and corneal sensitivity.ResultsThe decrease in subbasal nerve density was less severe in SMILE-treated eyes than in FS-LASIK-treated eyes at 1 week (P = 0.0147), 1 month (P = 0.0243), and 3 months (P = 0.0498), but no difference was detected at the 6-month visit (P = 0.5277). The subbasal nerve density correlated positively with central corneal sensitivity in both groups (r = 0.416, P<0.0001, and r = 0.2567, P = 0.0038 for SMILE group and FS-LASIK group, respectively). The SMILE-treated eyes have a lower risk of developing peripheral empty space with epithelial cells filling in (P = 0.0005).ConclusionsThe decrease in subbasal nerve fiber density was less severe in the SMILE group than the FS-LASIK group in the first 3 months following the surgeries. The subbasal nerve density was correlated with central corneal sensitivity.

Background:The aim was to evaluate the repeatability of a new optical low-coherence reflectometric device Lenstar, as well as its agreement with the IOL Master and the Pentacam-HR system in myopes. Methods: In a prospective study, 56 eyes of 28 myopes were examined with the Lenstar, the IOL Master and the Pentacam-HR system. The repeatability of the Lenstar was assessed. Bland-Altman plots were used to analyse the agreement between the Lenstar and the IOL Master for axial length (AL), anterior chamber depth (ACD from corneal epithelium to lens surface), keratometry readings of flattest and steepest meridian (K1 and K2) and horizontal iris width (white-to-white distance; WTW) measurements and between the Lenstar and the Pentacam-HR system for central corneal thickness (CCT), ACD (from corneal endothelium to lens surface) and K1 and K2 readings. Results: The variability of the Lenstar was small for all recorded measurements. CCT measurements with the Lenstar and the Pentacam-HR system and ACD measurements with the Lenstar and the other two devices showed narrow 95% limits of agreement (LoA), which imply good agreement. In contrast, range and 95% LoA were clinically significantly different for AL, K1, K2 and WTW values between the Lenstar and the IOL Master as well as for K readings between the Lenstar and the Pentacam-HR system. Conclusions: The repeatability of the Lenstar is excellent. In clinical practice, the Lenstar and the Pentacam-HR system can be used interchangeably for CCT and ACD measurements but not for K readings. The Lenstar and the IOL Master can be used interchangeably for ACD measurements but not for AL, K readings or WTW distance values.