PURPOSE: To investigate lenticule decentration following small incision lenticule extraction (SMILE) via the pupil center or tear film mark centration method and compare induction of corneal higher order aberrations (HOAs) between the two methods. METHODS: This study analyzed decentration values obtained from tangential topography difference maps of 100 eyes (100 patients) undergoing SMILE with the pupil center (n = 50) or tear film mark (n = 50) centration method. Total HOAs and component aberrations were measured preoperatively and 6 months postoperatively. Relationships between the magnitudes of decentration and induced corneal HOAs were assessed. RESULTS: Both vertical and total decentered displacement were significantly different ( P < .001) between the two centration groups. A significant relationship between the preoperative pupillary offset and decentration was noted in the pupil center group ( P < .001), but not in the tear film mark group ( P = .530). Significantly greater induction of total HOAs, coma, and vertical coma (all P < .001), as well as horizontal coma ( P = .001) and spherical aberration ( P = .023), were observed in the pupil center group. Association between the total decentered displacement and induced total HOAs ( P < .001), as well as all other significantly increased phenomena, was also significant in the pupil center group. Differences in decentered displacement and induced corneal HOAs were significant for preoperative pupillary offset (angle kappa) greater than 200 µm, but not for angle kappa less than 200 µm. CONCLUSIONS: SMILE with tear film mark centration can yield improved treatment centration and less induction of total HOAs, coma, and spherical aberrations. [ J Refract Surg . 2020;36(4):239–246.]

PURPOSE: To investigate 2-year visual outcomes, stability, and predictability after allogenic lenticule implantation in a 100-µm pocket for moderate to high hyperopia correction. METHODS: In this prospective case series, 14 eyes of 9 patients with moderate to high hyperopia ranging from +3.00 to +8.00 diopters sphere were included between March and September 2018. Allogenic lenticules extracted from myopic small incision lenticule extraction were implanted into a pocket created by femtosecond laser at a 100-µm depth in recipients with hyperopia. All patients were followed up for 2 years. Uncorrected (UDVA) and corrected (CDVA) distance visual acuity, manifest refraction, corneal topography, Fourier-domain optical coherence tomography, and in vivo confocal microscopy were examined. RESULTS: At postoperative 2 years, 2 eyes (14.3%) gained one line of CDVA, 11 eyes (78.6%) had unchanged CDVA, and 1 eye (7.1%) lost one line of CDVA. No eyes lost two or more lines of CDVA. Twelve of the treated eyes (85.7%) had postoperative uncorrected near visual acuity equal to or better than pre-operative values. The spherical equivalent decreased from +5.53 ± 1.45 D preoperatively to −0.60 ± 1.20 D at postoperative year 2 ( P < .001). The anterior mean keratometric readings increased from 42.41 ± 1.03 D preoperatively to 48.38 ± 1.98 D at postoperative year 2 ( P < .001). Of 14 treated eyes, 10 eyes (71.4%) had spherical equivalent within ±1.00 D. CONCLUSIONS: The findings suggest that allogenic lenticule transplantation may be a promising option for the correction of moderate to high hyperopia. [ J Refract Surg . 2021;37(11):734–740.]

Purpose: The aim of this study was to compare visual outcomes after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) for high myopia. Methods: In this prospective, comparative study, a total of 52 eyes of 34 consecutive highly myopic patients with spherical equivalent within the range of –8.00 to –10.00 diopters were recruited. Twenty-three eyes of 16 patients were in the FS-LASIK group and 29 eyes of 18 patients were in the SMILE group. Visual outcomes and wavefront aberrations were analyzed preoperatively and 6 months postoperatively. Results: At the postoperative 6-month visit, 96.6% in the SMILE group and 91.3% in the FS-LASIK group achieved unchanged or better corrected distance visual acuity (CDVA). As for uncorrected distance visual acuity (UDVA), 96.6% in the SMILE group and 95.7% in the FS-LASIK group achieved UDVA of 20/20 or better. As for wavefront aberrations, high-order aberrations (HOAs) and spherical aberrations increased significantly after surgery in both groups relative to corresponding preoperative values (p < 0.001), and vertical coma increased after SMILE (p < 0.001). No statistically significant differences in changes of HOAs (p =0.90), spherical aberrations (p = 0.07), horizontal coma (p = 0.56), coma (p =0.08), horizontal trefoil (p =0.19), vertical trefoil (p = 0.90), and trefoil (p = 0.45) were detected between the 2 groups, except for vertical coma (p < 0.01). Conclusions: SMILE is as effective as FS-LASIK in correcting high myopia, but attention should be paid to the induction of vertical coma in highly myopic patients following a SMILE procedure.

PURPOSE: To describe the first use of toric lenticule implantation with the triple marking method to correct hyperopia and hyperopic astigmatism following small incision lenticule intrastromal keratoplasty (SMI-LIKE). METHODS: Five eyes of four patients with hyperopia (+5.25 to +9.50 diopters sphere) were included. Allogenic toric lenticules extracted using myopic small incision lenticule extraction were implanted and rotated into a femtosecond laser–created stromal pocket in hyperopic recipients with triple marking. The uncorrected (UDVA) and corrected (CDVA) distance visual acuities, manifest refraction, corneal topography, and Fourier-domain optical coherence tomography images were examined 6 months postoperatively. RESULTS: Six months after surgery, 4 eyes (80%) gained two or more lines of UDVA, and 1 eye (20%) had unchanged UDVA. No eyes lost any lines of CDVA. The spherical equivalent decreased from +6.23 ± 1.34 diopters (D) preoperatively to −0.35 ± 0.27 D postoperatively. The mean refractive astigmatism also decreased significantly from −2.15 ± 1.10 D preoperatively to −0.70 ± 0.21 D postoperatively. Of 5 treated eyes, 2 (40%) had postoperative astigmatism within ±0.50 diopters cylinder and 5 (100%) within ±1.00 diopters cylinder. Corneal topography showed a significant increase in the anterior surface keratometry value, whereas corneal astigmatism decreased from 2.62 ± 1.55 to 1.10 ± 0.44 D. Vector analyses suggested good predictability and efficacy for astigmatism correction. CONCLUSIONS: Implantation of toric lenticules following SMI-LIKE with the triple marking method is a feasible alternative for correcting hyperopia and hyperopic astigmatism, and the short-term results seem safe and stable. [ J Refract Surg . 2022;38(2):82–88.]

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PURPOSE: To investigate the achieved optical zone and functional optical zone in myopic eyes with high astigmatism after small incision lenticule extraction (SMILE). METHODS: Seventy-five eyes of 75 consecutive patients with myopia before SMILE were included and divided into two groups (no astigmatism group: without astigmatism vs high astigmatism group: with astigmatism > 2.00 diopters). The achieved optical zone, functional optical zone, and corneal aberrations were compared using Scheimpflug imaging at 6 months postoperatively. Correlations between corneal aberrations and functional optical zone were analyzed. RESULTS: The mean achieved optical zone diameter was smaller in the no astigmatism group than in the high astigmatism group. There were no significant differences in achieved optical zone among the different meridians in each group. The mean functional optical zone diameter was significantly smaller in the no astigmatism group than in the high astigmatism group. Compared with the programmed optical zone, significant reduction of the functional optical zone was found in the two groups. The reduction of the functional optical zone was significantly smaller in the high astigmatism group than in the no astigmatism group, except for the 60°, 90°, and 120° meridians. There were significant correlations between the functional optical zone area and the induced corneal aberrations in the high astigmatism group, except for horizontal coma, whereas significant correlations of functional optical zone with total higher order aberrations and spherical aberration were detected in the no astigmatism group. CONCLUSIONS: Myopic eyes with high astigmatism following SMILE had a circular achieved optical zone, but the functional optical zone was oval and larger than in eyes without astigmatism. Moreover, a lower spherical aberration was observed in the patients with high astigmatism. [ J Refract Surg . 2022;38(4):243–249.]

Introduction: To compare central corneal thickness (CCT) reduction after small incision lenticule extraction (SMILE) and femtosecond laser-assisted in situ keratomileusis (FS-LASIK) in eyes with high myopia. Methods: In this prospective, consecutive study, 70 eyes with high myopia undergoing SMILE (n = 35) or FS-LASIK (n = 35) were recruited. Corneal topography images were acquired using the Pentacam HR imaging system preoperatively and at 1 day, 1 month, and 6 months postoperatively. Predicted CCT reduction was extracted directly from the Visu-Max femtosecond laser system or MEL 80 excimer laser platform. The achieved CCT reduction was determined using corneal thickness difference maps from the Pentacam. Comparative statistics and linear regression analyses were performed to evaluate the predictability in stromal thickness reduction. Results: The mean predicted CCT reductions were 152.9 ± 6.7 lm and 150.9 ± 7.3 lm in the FS-LASIK and SMILE groups, respectively, with no statistical difference. For each follow-up time, no significant difference was noted in the two groups in the achieved CCT reduction. At 6-month follow-up, the CCT reductions were overestimated to be 23.06 ± 6.97 lm and 28.29 ± 13.92 lm in the SMILE and FS-LASIK groups, respectively (P = 0.003), showing statistical difference. Regression analysis revealed that the positive correlation between achieved and predicted CCT reductions was stronger in SMILE (R 2 = 0.5065, P \ 0.001) than in FS-LASIK (R 2 = 0.2237, P = 0.004). Overestimated CCT reduction was not correlated with predicted CCT reduction in either group. Conclusions: Systematically overestimated CCT reduction is found after SMILE and FS-LASIK in high myopia correction. Deviations between planned and achieved CCT reductions are more pronounced in FS-LASIK than in SMILE.

PURPOSE: To compare the functional optical zone (FOZ) in eyes with high myopia with high astigmatism after small incision lenticule extraction (SMILE) and femtosecond laser–assisted laser in situ keratomileusis (FS-LASIK). METHODS: In total, 45 eyes of 45 patients with high myopia with astigmatism greater than 2.00 diopters (D) who underwent SMILE or FS-LASIK were enrolled. The FOZ, optical zone decentration, and corneal aberrations were analyzed using Scheimpflug imaging. These values were then compared between the two groups 6 months postoperatively. RESULTS: No postoperative complications were observed during follow-up. The mean FOZ diameter was 5.03 ± 0.31 mm for the FS-LASIK group and 5.24 ± 0.27 mm for the SMILE group ( P = .007), corresponding to reductions of 1.18 ± 0.23 and 1.01 ± 0.21 mm, respectively, compared with the programmed optical zone (POZ) ( P = .013). A significant difference was noted in the FOZ on the short axis between the two groups ( P = .002), whereas no significant difference was observed on the long axis ( P = .088). The FOZ area in the FS-LASIK and SMILE groups was 65.39 ± 6.14% and 70.09 ± 5.46% of the POZ area, respectively ( P = .010). There was no significant difference in decentration between the two groups (0.29 ± 0.13 mm for the FS-LASIK group vs 0.30 ± 0.13 mm for the SMILE group, P = .798). A significant increase in spherical aberration was observed in the FS-LASIK group ( P < .001). However, the induction of vertical coma was higher in the SMILE group than in the FS-LASIK group ( P = .002). CONCLUSIONS: Eyes with high myopia with high astigmatism following SMILE achieved a larger FOZ and less spherical aberration but a larger vertical coma introduction than following FS-LASIK. [ J Refract Surg . 2022;38(9):595–601.]