To investigate the changes in dry eye symptoms and clinical signs and corneal sensitivity after small incision lenticule extraction (SMILE) and femtosecond LASIK (femto-LASIK). Prospective, non-randomized comparative study. The study included a total of 71 eyes of 71 patients; the SMILE group comprised 38 eyes of 38 patients, and the femto-LASIK group comprised 33 eyes of 33 patients. Ocular Surface Disease Index (OSDI), Tear film breakup time (TBUT), the Schirmer test without anesthesia (S1T), corneal fluorescein staining, and central corneal sensation were evaluated before surgery and at 1 week, 1 month, 3 months, and 6 months after surgery. OSDI scores in both groups were increased immediately and returned to preoperative level at 1 month after surgeries. The TBUT values in both groups were reduced after surgeries relative to their preoperative scores. Patients in SMILE group were less likely to have corneal staining compared with those in the femto-LASIK group ([odds ratio] OR = 0.50, 95% [confidence interval] CI 0.28 to 0.93, P = 0.03). Central corneal sensitivity was decreased at all postoperative time points in both groups. However, the central corneal sensation scores in the SMILE group were greater than that in the femto-LASIK group at all of the postoperative time points (all P<0.05). SMILE surgeries resulted in a short-term increase in dry eye symptoms, tear film instability, and loss of corneal sensitivity. Furthermore, SMILE surgeries have superiority over femto-LASIK in lower risk of postoperative corneal staining and less reduction of corneal sensation.

Purpose. To measure decentration following femtosecond laser small incision lenticule extraction (SMILE) for the correction of myopia and myopic astigmatism in the early learning curve, and to investigate its impact on visual quality. Methods. A total of 55 consecutive patients (100 eyes) who underwent the SMILE procedure were included. Decentration was measured using a Scheimpflug camera 6 months after surgery. Uncorrected and corrected distance visual acuity (UDVA, CDVA), manifest refraction, and wavefront errors were also measured. Associations between decentration and the preoperative spherical equivalent were analyzed, as well as the associations between decentration and wavefront aberrations. Results. Regarding efficacy and safety, 40 eyes (40%) had an unchanged CDVA; 32 eyes (32%) gained one line; and 11 eyes (11%) gained two lines. Fifteen eyes (15%) lost one line of CDVA, and two eyes (2%) lost two lines. Ninety-nine of the treated eyes (99%) had a postoperative UDVA better than 1.0, and 100 eyes (100%) had a UDVA better than 0.8. The mean decentered displacement was 0.17 ± 0.09 mm. The decentered displacement of all treated eyes (100%) was within 0.50 mm; 70 eyes (70%) were within 0.20 mm; and 90 eyes (90%) were within 0.30 mm. The vertical coma showed the greatest increase in magnitude. The magnitude of horizontal decentration was found to be associated with an induced horizontal coma. Conclusions. This study suggests that, although mild decentration occurred in the early learning curve, good visual outcomes were achieved after the SMILE surgery. Special efforts to minimize induced vertical coma are necessary.

PURPOSE: To evaluate the safety, effectiveness, stability, and predictability of implanting autologous lenticules obtained from small incision lenticule extraction for the treatment of hyperopia. METHODS: Five patients (10 eyes) with one myopic eye and one hyperopic eye were enrolled. The myopic eye was treated with small incision lenticule extraction; a lenticule was extracted and subsequently implanted in the hyperopic eye. Follow-up was at 1 day, 1, 3, 6, and 9 months, and 1 year postoperatively. Patients received a complete ophthalmologic examination at each visit, including uncorrected distance visual acuity, corrected distance visual acuity, anterior segment optical coherence tomography, and corneal topography. RESULTS: There were no complications in any eye during follow-up. Compared with preoperative levels, at the last follow-up visit the eyes with lenticule implantation showed mean spherical equivalent reduced by 5.53 diopters (residual spherical equivalent was +1.13 to −2.63 diopters), mean uncorrected distance visual acuity increased approximately two lines (approximately 20/63 to 20/40 Snellen), and corrected distance visual acuity in 4 (80%) eyes gained one line, 2 (40%) eyes gained two lines, and 1 (20%) eye gained more than two lines. There was no significant difference ( P > .05) in spherical equivalent compared with 1 day postoperatively and the last follow-up visit. Corneal topography showed that the lenticule was uniform and located well; anterior segment optical coherence tomography images showed that the lenticule was transparent and the demarcation line was visible. CONCLUSIONS: Implanting an autologous lenticule obtained by small incision lenticule extraction for hyperopia might be safe, effective, and stable, but its predictability should be improved in the future. [ J Refract Surg. 2015;31(6):374–379.]

PURPOSE: To investigate the differences in corneal deformation parameters after femtosecond laser small incision lenticule extraction (SMILE), laser-assisted subepithelial keratomileusis (LASEK), and femtosecond laser-assisted LASIK (FS-LASIK). METHODS: In this retrospective study, 17 eyes of 17 patients after SMILE, 18 eyes of 18 patients after LASEK, and 17 eyes of 17 patients after FS-LASIK were included. Corneal deformation parameters were measured with the CorVis ST tonometer (Oculus Optikgeräte GmbH, Wetzlar, Germany) 3 months postoperatively. RESULTS: The mean value of deformation amplitude of the FS-LASIK group was significantly higher than that of the LASEK group ( P = .022). The mean value of applanation time (applanation 1) of the LASEK group was significantly higher than that of the FS-LASIK group ( P = .038). No significant difference was detected in the mean values of deformation amplitude and applanation time (applanation 1) ( P > .05) between the LASEK and SMILE groups or between the SMILE and FS-LASIK groups. Multiple linear regression model analysis revealed that after adjustment for age and preoperative central corneal thickness and manifest refraction spherical equivalent, the significance of the difference in the mean values of applanation time (applanation 1) and deformation amplitude between the LASEK and FS-LASIK groups were P = .084 and .059, respectively. In all three groups, the values of applanation 1 negatively correlated to those of applanation time (applanation 2) (SMILE: r = −0.577, P = .015; LASEK: r = −0.833, P < .001; FS-LASIK: r = −0.516, P = .034) and deformation amplitude (SMILE: r = −0. 556, P = .021; LASEK: r = −0.877, P < .001; FS-LASIK: r = −0.509, P = .037). CONCLUSIONS: Applanation time (applanation 1) and deformation amplitude (as measured with the CorVis ST tonometer) may be helpful in assessing corneal biomechanical changes after corneal refractive surgery. The relations between these parameters should be discussed in further studies. [ J Refract Surg. 2014;30(5):310–318. ]

PURPOSE: To study microdistortions in Bowman’s layer after femtosecond laser small incision lenticule extraction (SMILE) using Fourier-domain optical coherence tomography (OCT) and to investigate possible sources and potential visual impacts. METHODS: A nonrandomized controlled prospective study enrolled 52 eyes of 29 consecutive patients undergoing SMILE, with spherical equivalent of −6.33 ± 1.88 diopters and 4.2 mm superior incision. The micro-distortions in Bowman’s layer were counted at 1 day, 1 week, and 1 month postoperatively and at long-term follow-up. Another 38 eyes of 20 patients undergoing femtosecond laser-assisted LASIK (FS-LASIK) were examined at 1 day and long-term postoperatively as the control group. RESULTS: Microdistortions in Bowman’s layer were observed by OCT, with no clinically significant corneal striae under slit-lamp microscopy, in 46 eyes (88.5%) on day 1 after SMILE and in 16 eyes (42.1%) after FS-LASIK, with more in SMILE eyes than in FS-LASIK eyes. The amount decreased at 1 week and then remained stable. There were more microdistortions in the center area than in the periphery in both groups. Microdistortions were more in the inferior than the superior quadrant on the first day after SMILE but there was no difference at long-term follow-up. Microdistortions after SMILE were associated with the refractive lenticule thickness and surgery order but had no significant impact on long-term visual outcomes or wavefront aberrations. CONCLUSIONS: Microdistortions in Bowman’s layer after SMILE were associated with the refractive lenticule thickness and surgery order. The microdistortions remained stable after 1 week and had no impact on long-term visual performance. [ J Refract Surg. 2013;29(10):668–674.]

To determine the incidence and clinical features of diffuse lamellar keratitis (DLK) after small-incision lenticule extraction (SMILE). Department of Ophthalmology, Eye and ENT Hospital of Fudan University, Shanghai, China. Retrospective case control study. Small-incision lenticule extraction for myopia was performed from September 1, 2011, to October 31, 2013. Preoperative clinical characteristics; treatment parameters; and intraoperative and postoperative complications, including the incidence, severity, clinical outcome, and resolution of DLK, were recorded. The independent t test, chi-square test, univariate repeated measures, and multivariate linear regression analysis were used to make statistical comparisons between eyes that developed DLK and those that did not. The study enrolled 1112 eyes (590 patients). Eighteen eyes (1.6%) (11 patients) developed DLK. These patients presented 1 to 3 days postoperatively with mild to moderate inflammation. Thirteen eyes (72.2%) had stage 1 DLK, 4 (22.2%) had stage 2, and 1 (5.6%) had stage 3. After intensive treatment with topical corticosteroids, the stage 1 and stage 2 cases resolved within 3 weeks and the stage 3 case resolved in 1 month. The postoperative corrected distance visual acuity was the same or better than preoperatively in all eyes. There was a statistically significant increase in the incidence of DLK with thinner lenticules (P = .02) and larger diameter lenticules (P = .01), although multifactorial analysis showed lenticule thickness to be the only factor (P = .03). Diffuse lamellar keratitis is a potential complication after small-incision lenticule extraction, although it had a low incidence. The risk factors for DLK must be further elucidated. No author has a financial or proprietary interest in any material or method mentioned.