The centration of the treatment zone as measured by the Pentacam was better for patient-controlled fixation during SMILE than active eye tracker-assisted FS-LASIK.

DMEK patients showed faster rehabilitation and higher BSCVA at all postoperative visits; however, the decline in graft's endothelial cell count and change in the spherical equivalent were similar for both procedures.

Purpose. To evaluate corneal clarity and visual outcomes after small-incision lenticule extraction (SMILE) and compare them to femtosecond laser-assisted in situ keratomileusis (FS-LASIK). Materials and Methods. Fifty-eight myopic eyes of 33 patients who underwent SMILE were compared to 58 eyes of 33 patients treated with FS-LASIK. All procedures were performed using VisuMax® femtosecond laser and MEL 80® excimer laser (Carl Zeiss Meditec AG, Germany). Pentacam™ (Oculus, Germany) was used for pre- and 3-month postoperative corneal densitometry (CD) analysis. CD was evaluated at 3 optically relevant, concentric radial zones (0–2 mm, 2–6 mm, and 0–6 mm annulus) around the corneal apex and at 3 different anatomical corneal layers (anterior, central, and posterior). Associations of postoperative CD values with the lenticule thickness and ablation depth were examined. Preoperative and postoperative corrected distance visual acuity (CDVA) values were also compared. Results. After SMILE, the total CD (all corneal layers) at 0–6 mm annulus showed no significant change compared to preoperative values (P = 0.259). After FS-LASIK, the total CD was significantly reduced (P = 0.033). Three-month postoperative CD showed no significant differences between the 2 groups for all examined annuli (0–2 mm: P = 0.569; 2–6 mm: P = 0.055; and 0–6 mm: P = 0.686). Total CD after SMILE at 0–6 mm annulus displayed a weak negative association with the lenticule thickness (P = 0.079, R2 = 0.0532) and after FS-LASIK displayed a weak negative association with the ablation depth (P = 0.731, R2 = 0.0015). Postoperative CDVA was similar for both groups (P = 0.517). Conclusion. Quantification of corneal clarity using the Scheimpflug CD showed similar results before and 3 months after SMILE. Compared to FS-LASIK, no significant differences of corneal clarity and CDVA were found 3 months postoperatively.

Purpose: To evaluate and compare the predictability of intraocular lens (IOL) power calculation after small-incision lenticule extraction (SMILE) for myopia and myopic astigmatism. Setting: Department of Ophthalmology, Philipps University of Marburg, Marburg, Germany. Design: Retrospective comparative case series. Methods: Preoperative evaluation included optical biometry using IOLMaster 500 and corneal tomography using Pentacam HR. The corneal tomography measurements were repeated at 3 months postoperatively. The change of spherical equivalent due to SMILE was calculated by the manifest refraction at corneal plane (SMILE-Dif). A theoretical model, involving the virtual implantation of the same IOL before and after SMILE, was used, and the IOL power calculations were performed using ray tracing (OKULIX, version 9.06) and third- (Hoffer Q, Holladay 1, and SRK/T) and fourth-generation (Haigis-L and Haigis) formulas. The difference between the IOL-induced refractive error at corneal plane before and after SMILE (IOL-Dif) was compared with SMILE-Dif. The prediction error (PE) was calculated as the difference between SMILE-Dif–IOL-Dif. Results: The study included 204 eyes that underwent SMILE. The PE with ray tracing was −0.06 ± 0.40 diopter (D); Haigis-L, −0.39 ± 0.62 D; Haigis, 0.70 ± 0.48 D; Hoffer Q, 0.84 ± 0.47 D; Holladay 1, 1.21 ± 0.51 D; and SRK/T, 1.46 ± 0.54 D. The PE with ray tracing was significantly smaller compared with that of all formulas (P ≤ .001). The PE variance with ray tracing was σ2 = 0.159, being significantly more homogenous compared with that of all formulas (P ≤ .011, F ≥ 6.549). Ray tracing resulted in an absolute PE of 0.5 D or lesser in 81.9% of the cases, followed by Haigis-L (53.4%), Haigis (35.3%), Hoffer Q (25.5%), Holladay 1 (6.4%), and SRK/T (2.9%) formulas. Conclusions: Ray tracing was the most accurate approach for IOL power calculation after myopic SMILE.

PurposeEvidence regarding whether or not antibiotic prophylaxis is beneficial in preventing post-operative surgical site infection in adult inguinal hernia repair is conflicting. A recent Cochrane review based on 17 randomised trials did not reach a conclusion on this subject. This study aimed to describe the current practice and determine whether clinical equipoise is prevalent.MethodsSurgeons in training were recruited to administer the Survey of Hernia Antibiotic Prophylaxis usE survey to consultant-level general surgeons in London and the south-east of England on their practices and beliefs regarding antibiotic prophylaxis in adult elective inguinal hernia repair. Local prophylaxis guidelines for the participating hospital sites were also determined.ResultsThe study was conducted at 34 different sites and received completed surveys from 229 out of a possible 245 surgeons, a 93 % response rate. Overall, a large majority of hospital guidelines (22/28) and surgeons’ personal beliefs (192/229, 84 %) supported the use of single-dose pre-operative intravenous antibiotic prophylaxis in inguinal hernia repair, although there was considerable variation in the regimens in use. The most widely used regimen was intravenous co-amoxiclav (1.2 g). Less than half of surgeons were adherent to their own hospital antibiotic guidelines for this procedure, although many incorrectly believed that they were following these.ConclusionIn the south-east of England, there is a strong majority of surgical opinion in favour of the use of antibiotic prophylaxis in this procedure. It is therefore likely to be extremely difficult to conduct further randomised studies in the UK to support or refute the effectiveness of prophylaxis in this commonly performed procedure.

PurposeTo compare endothelial cell loss and complications following Descemet membrane endothelial keratoplasty (DMEK) with use of three commercially available injectors.MethodsFrom 179 consecutive DMEK procedures, 66 cases with uncomplicated graft preparation and completed 12-month follow-up were included in this retrospective study. According to the injector used, 3 groups were formed: group 1 (D.O.R.C. injector, n=16), group 2 (Geuder injector, n=24), and group 3 (Pasteur laboratory pipette, n= 26). Endothelial cell density (ECD) and endothelial cell loss were evaluated preoperatively and at 3, 6 and 12 months postoperatively; surgery-related complications were recorded.ResultsDonor ECD was 2416±179 cells/mm (group 1), 2417±164 cells/mm (group 2), and 2478±234 cells/mm (group 3). At 12 months postoperatively ECD was 1473±403 cells/mm (group 1), 1379±317 cells/mm (group 2), and 1316±456 cells/mm (group 3) (P=0.533, ANOVA). Endothelial cell loss 12 months postoperatively was 39±15% (group 1), 43±13% (group 2), and 47±17% (group 3) (P=0.386, ANOVA). A single case of iris bleeding and reflux of the graft out of the anterior chamber (both in group 3) was noted. Partial graft detachment occurred in group 1 (n=1), group 2 (n=5), and group 3 (n=7) and rebubbling was performed in 6% (group 1), 17% (group 2), and 27% (group 3).ConclusionsTo our knowledge, this is the first clinical study assessing the safety of three different DMEK injectors. Group 1 (D.O.R.C injector) showed the least and group 3 (Pasteur laboratory pipette) the highest endothelial cell loss without reaching statistical significance at 12 months after surgery. Therefore, the graft injector may be chosen according to surgeon's preference.

PURPOSE: To investigate the biomechanical properties of the ex vivo human paired corneas after completion of photorefractive keratectomy (PRK) versus small incision lenticule extraction (SMILE) in the same donor. METHODS: In this experimental study, 13 pairs of human corneas unsuitable for transplantation were equally divided into two groups. Corneal thickness was measured in each eye directly before laser refractive surgery. Corneas from the right eye were treated with PRK and corneas from the left eye with SMILE. All corneas were subjected to a refractive correction of −10.00 diopters (D) sphere and −0.75 D cylinder at 0° with a 7 mm zone, using either surface ablation (PRK) or 130 µm cap (SMILE). For two-dimensional biomechanical measurements, corneoscleral buttons underwent two testing cycles (preconditioning stress-strain curve from 0.03 to 9.0 N and stress-relaxation at 9.0 N during 120 seconds) to analyze the elastic and viscoelastic material properties. The effective elastic modulus was calculated. Statistical analysis was performed with a confidence interval of 95%. RESULTS: In stress-strain measurements, the effective elastic modulus was not significantly different ( P = .081) between SMILE (9.58 ± 4.26 MPa) and PRK (11.9 ± 4.90 MPa). The effect size was medium (Cohen's d = 0.58). In stress-relaxation measurements, the remaining stress was not significantly different ( P = .878) between SMILE (122 ± 33 kPa) and PRK (123 ± 30 kPa). CONCLUSIONS: The lenticule extraction procedure (SMILE) and the surface ablation technique (PRK) may be considered equivalent in terms of biomechanical stability when measured experimentally in ex vivo human fellow eye corneas. [ J Refract Surg. 2019;35(8):501–505.]

A single rebubbling procedure does not increase the CD of the central cornea and but results in significantly higher ECL compared with uneventful DMEK with complete graft attachment.