Femtosecond Laser In Situ Keratomileusis Group Research Articles

Differences in change of post-operative antioxidant levels between laser-assisted lenticule extraction and femtosecond laser insitu keratomileusis.

To evaluate the change of total antioxidant capacity (TAC) and ascorbic acid (AA) between femtosecond laser insitu keratomileusis (FS-LASIK) and laser-assisted lenticule extraction (LALEX). A prospective non-randomized study was conducted, and 33 and 75 eyes that had undergone FS-LASIK or LALEX surgeries were enrolled, respectively. The tear films near corneal incisions were collected, and the concentrations of TAC and AA were determined. The generalized linear mixed model was adopted to calculate the adjusted odds ratio (aOR) with 95% confidence interval (CI) of TAC and AA between the two groups. The AA reduction was significant 1 month after the LALEX and FS-LASIK procedures (both p < 0.05), and the decrement in AA level was significantly larger in the FS-LASIK group compared to the LALEX group (p = 0.0002). In the subgroup analysis, the LALEX group demonstrated a lower decrement in TAC level in the individuals with dry eye disease (DED) than the FS-LASIK group (p = 0.0424), and the LALEX group demonstrated a significantly lower AA decrement in the participants with high myopia (p = 0.0165) and DED (p = 0.0043). The LALEX surgery causes lesser AA decrement compared to FS-LASIK surgery especially for the patients with DED.

Sub-Bowman keratomileusis versus femtosecond laser in situ keratomileusis on the long-term visual recovery: A comparative study.

To explore the long-term visual quality of the same subjects after sub-Bowman keratomileusis (SBK) or femtosecond laser in situ keratomileusis (FS-LASIK). This prospective study included patients screened for corneal refractive surgery at the Refractive Surgery Center of our Hospital between November 2017 and March 2018. One eye underwent SBK, while the other eye underwent FS-LASIK. Total higher-order aberrations, coma aberrations, and clover aberrations were evaluated before and at 1 month and 3 years after the procedure. The visual satisfaction of both eyes was investigated, respectively. The participants completed a surgical satisfaction questionnaire. Thirty-three patients were included. There were no significant differences in total higher-order aberrations, coma aberrations, and clover aberrations between the two procedures before and 1 month and 3 years after surgery (all P > 0.05), except for the total coma aberrations in FS-LASIK were significantly higher compared with the SBK group at 1 month after surgery [0.51 (0.18, 0.93) vs. 0.77 (0.40, 1.22), P = 0.019]. The surgical satisfaction questionnaire scores of the SBK group and the FS-LASIK group were 9.8 ± 0.8 and 9.8 ± 0.8, respectively, at 1 month, and 9.7 ± 0.9 and 9.7 ± 1.0, respectively, at 3 years (all P > 0.05). There were no differences in corneal aberrations and satisfaction between SBK and FS-LASIK procedures at 1 month and 3 years.

Comparison of refractive and visual outcomes between image-guided system-assisted small-incision lenticule extraction and wavefront-optimized FS-LASIK in treatment of high astigmatism.

To compare the refractive and visual results of image-guided system-assisted small-incision lenticule extraction (IGA-SMILE) and wavefront-optimized femtosecond laser in situ keratomileusis (FS-LASIK) in the treatment of high astigmatism. Osmangazi Aritmi Hospital, Bursa, Turkey. Retrospective. This retrospective case-matched study included 64 eyes that had undergone IGA-SMILE and 64 eyes that had undergone wavefront-optimized FS-LASIK. The mean preoperative myopia and astigmatism were -4.05 ± 1.98 diopter (D) and 3.11 ± 1.06 D in the IGA-SMILE group and -4.21 ± 2.23 D and -3.15 ± 0.62 D in the FS-LASIK group, respectively. One year later, visual and refractive results were compared in the groups. Vector analysis based on Alpins method was performed to evaluate astigmatic treatment. 128 eyes of 128 patients were included in this study. At 1 year, the residual astigmatism was -0.21 ± 0.25 D in the IGA-SMILE group and -0.21 ± 0.24 D in the FS-LASIK group ( P = .305). In the IGA-SMILE group, 57 eyes (89.1%) achieved uncorrected distance visual acuity of 20/20 or better, as did 56 eyes (85.9%) in the FS-LASIK group. Vector analysis results demonstrated that the difference vectors were 0.22 ± 0.24 D and 0.21 ± 0.22 D ( P = .230), the correction indexes were 0.95 ± 0.08 and 0.95 ± 0.08 ( P = .239), and the indices of success were 0.08 ± 0.09 and 0.08 ± 0.09 ( P = .248) in the IGA-SMILE and the FS-LASIK groups, respectively. The combination of an image-guided system with SMILE resulted in high efficacy and safety indices that were comparable with FS-LASIK surgery.

Comparative study of objective visual quality between FS-LASIK and SMART in myopia.

To compare the changes in the objective visual quality of patients with low and moderate myopia postoperatively after transepithelial photorefractive keratectomy using the smart pulse technology (SMART) and femtosecond laser in situ keratomileusis (FS-LASIK). Corneal higher-order aberrations (HOAs), horizontal coma, vertical coma and spherical aberration were measured using Pentacam, and cutoff for modulation transfer function (MTF cutoff), objective scatter index (OSI) and Strehl ratio (SR) was measured using an optical quality analysis system (OQAS-II), before and after operation at 1, 3, and 6mo, and data were analyzed by repeated measurement two-way analysis of variance. The difference in uncorrected distance visual acuity between SMART and FS-LASIK was statistically significant only 1wk postoperatively. Approximately 86.36% and 80.69% of patients with spherical equivalent (SE) in ±0.50 D were observed in the SMART and FS-LASIK groups, respectively. No significant difference was observed in SE between the two groups (P=0.509). The HOAs increased postoperatively compared with those before surgery in both groups (P<0.05). No significant difference in HOA, corneal horizontal coma, spherical aberration, ΔHOA, Δhorizontal coma, and Δspherical aberration were observed between the two group (P>0.05). Corneal vertical coma and Δcorneal vertical coma in the FS-LASIK group were higher than those in the SMART group (P<0.05). The OSI of both groups at 1mo after surgery was higher than that before surgery (P<0.05). At 3 and 6mo postoperatively, the OSI in the FS-LASIK group was slightly higher than that in the SMART group (P=0.040 and 0.047, respectively). At 6mo after surgery, the MTF cutoff was statistically significant different between the two groups (P=0.026). No significant difference in SR between the FS-LASIK and SMART groups was observed at 1, 3, and 6mo postoperatively (P>0.05). The HOAs increase and visual quality is delayed in both groups postoperatively, and the long-term objective visual quality after SMART is slightly better than that after FS-LASIK.

Corneal nerve repair and optical density in patients with high myopia after three kinds of corneal refractive surgery

Objective: To investigate the repair of subepithelial nerve fibers in different areas of the cornea and the difference of corneal transparency 12 months after small incision lenticule extraction (SMILE), femtosecond laser in situ keratomileusis (FS-LASIK) and excimer laser in situ keratomileusis (LASEK) in high myopia. Methods: A cohort study. From June 2018 to October 2019, 30 patients with high myopia (60 eyes) were selected for corneal refractive surgery in the Department of Ophthalmology, Affiliated Hospital of Qingdao University, including 16 females (32 eyes) and 14 males (28 eyes). According to the mode of operation, the patients were divided into the SMILE group (n=10), FS-LASIK group (n=11) and LASEK group (n=9). The repair of subepithelial nerves in different areas of the cornea was observed by laser confocal microscopy 12 months after operation,and the morphological parameters were analyzed by ACCMetrics software. The parameters included corneal nerve fiber density (CNFD), corneal nerve branch density (CNBD), corneal nerve fiber length (CNFL), corneal nerve fiber total branch density (CTBD) and corneal nerve fiber width. The Pentacam anterior segment analyzer was used to measure the optical density of the cornea in different diameters. The nerve fiber parameters and corneal optical density were compared by random block analysis of variance, and multiple comparisons were performed between groups by the Turkey test. Results: Twelve months after operation, there was no significant difference in the CNFD among the three groups(all P>0.05). The CNBD around the upper corneal incision in the SMILE group, FS-LASIK group and LASEK group was (7.81±7.93), (9.61±7.18) and (21.25±15.55) branches/mm2, respectively. The CTBD was (22.00±16.02), (24.44±11.42) and (54.37±22.13) branches/mm2, respectively. The values in the LASEK group significantly differed from the other two groups (HSD=2.823, -3.010, 3.053, -3.048, P<0.01). The CNFL was (9.19±3.25), (12.88±3.52) and (15.75±2.36) mm/mm2, respectively. The value in the SMILE group was significantly different (HSD=-3.151, -4.418; P<0.0l). The corneal optical density after SMILE was 13.16±0.72 in the 0-6 mm diameter area(HSD=-4.164, -4.489; P<0.01), 16.12±3.18 in the 6-12 mm diameter area(HSD=-3.918, -3.493;P<0.01) and 14.06±1.36 in the total diameter (HSD=-6.031, -5.519;P<0.01), which differed significantly from the other two groups. Conclusions: Twelve months after SMILE for high myopia, the nerve repair around the superior corneal incision is slightly worse than that after FS-LASIK and LASEK, but the nerve repair in other areas has some advantages, and the corneal transparency is better. (Chin J Ophthalmol, 2021, 57:268-276).

Comparison of anterior segment changes after femtosecond laser LASIK and SMILE using a dual rotating Scheimpflug analyzer

BackgroundTo compare the changes in the anterior segment after femtosecond laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) using a dual rotating Scheimpflug (DRS) analyzer (Galilei®; Ziemer Ophthalmology, Port, Switzerland).MethodsA total of 218 eyes of 109 patients who underwent FS-LASIK or SMILE for myopic correction were retrospectively studied. Ninety-eight eyes of 49 patients who underwent FS-LASIK were compared to 120 eyes of 60 patients treated with SMILE. A DRS analyzer was used for preoperative and 6-month postoperative anterior segment analyses. Measured variables included the central corneal thickness (CCT), anterior chamber depth (ACD), anterior and posterior keratometry (K), anterior and posterior best-fit sphere radius, and maximum posterior elevation (MPE).ResultsAfter the procedure, the amount of CCT decrease was higher in the SMILE group than in the FS-LASIK group, but it was not statistically significant. The MPE was significantly increased after both procedures (p < 0.001 and p = 0.001 in the FS-LASIK and SMILE groups, respectively), with the amount of elevation being higher after FS-LASIK than after SMILE even though it was not statistically significant. And there was a significant change in the steep and average posterior K in the FS-LASIK group (p = 0.006 and 0.001, respectively), but not in the SMILE group.ConclusionsRegarding changes in the MPE and posterior K, changes in the posterior corneal surface were greater after FS-LASIK than after SMILE.Trial registrationThe trial registration number: KCT0003628. Date of registration: 15 March 2019.

Uncorrected visual acuity, postoperative astigmatism, and dry eye symptoms are major determinants of patient satisfaction: a comparative, real-life study of femtosecond laser in situ keratomileusis and small incision lenticule extraction for myopia.

PurposeTo compare factors affecting patient satisfaction after femtosecond laser in situ keratomileusis (FS-LASIK) and small incision lenticule extraction (SMILE) for myopia in the real-life situation study.MethodsThe SMILE group included 100 eyes (51 patients) and the FS-LASIK group 200 eyes (102 patients). In addition to clinical examination, dry eye symptoms and patient satisfaction with far and near vision were reported and graded on the visual analog scale preoperatively and one month after the operation. Case–control pairs were selected for the SMILE patients from FS-LASIK-treated patients to ensure the homogeneity in spherical equivalent refraction, preoperative dry eye, and visual satisfaction.ResultsEighty percent of SMILE eyes and 83% of FS-LASIK eyes achieved an uncorrected distance visual acuity of 20/20 or better. Predictability (±0.5 D of mean target spherical equivalent refraction) was 91% in SMILE and 93.5% in FS-LASIK. No eyes lost two or more Snellen lines of corrected distance visual acuity. Based on case–control pairs, dry eye symptoms remained the same after one month in the FS-LASIK-treated eyes (P=0.87) but decreased in the SMILE-treated eyes (P=0.01) compared with the preoperative situation. Patient satisfaction with far vision improved significantly in both groups (P<0.001), but satisfaction with near vision improved significantly only in FS-LASIK (P<0.001) and not in SMILE (P=0.58). There was more postoperative astigmatism in SMILE in comparison with FS-LASIK (P=0.002).ConclusionsIn a real-life situation, patients with preoperative dry eye experience were often directed to the SMILE operation, which resulted in beneficial decrease in their dry eye symptoms. Patient satisfaction with far vision decreased with increasing dry eye symptoms and postoperative astigmatism in both SMILE- and FS-LASIK-treated emmetropic patients. Safety, efficacy, and predictability were comparable in both treatments.

Clinical outcomes of small incision lenticule extraction versus femtosecond laser-assisted LASIK for myopia: a Meta-analysis.

To evaluate the possible differences in visual quality between small incision lenticule extraction (SMILE) and femtosecond laser in situ keratomileusis (FS-LASIK) for myopia. A Meta-analysis was performed. Patients were from previously reported comparative studies treated with SMILE versus FS-LASIK. The PubMed, EMBASE, Cochrane, Web of Science and Chinese databases (i.e. WANFANG and CNKI) were searched in Nov. of 2016 using RevMan 5.1 version software. The differences in visual acuity, aberration and biomechanical effects within six months postoperatively were showed. Twenty-seven studies including 4223 eyes were included. No significant differences were observed between SMILE and FS-LASIK in terms of the proportion of eyes that lost one or more lines of corrected distance visual acuity after surgery (P=0.14), the proportion of eyes achieving an uncorrected distance visual acuity of 20/20 or better (P=0.43), the final refractive spherical equivalent (P=0.89), the refractive spherical equivalent within ±1.00 diopter of the target values (P=0.80), vertical coma (P=0.45) and horizontal coma (P=0.06). Compared with the FS-LASIK group, total higher-order aberration (P<0.001) and spherical aberration (P<0.001) were higher and the decrease in corneal hysteresis (P=0.0005) and corneal resistance factor (P=0.02) were lower in the SMILE group. SMILE and FS-LASIK are comparable in efficacy, safety and predictability for correcting myopia. However, the aberration in the SMILE group is superior to that in the FS-LASIK group, and the loss of biomechanical effects may occur less frequently after SMILE than after FS-LASIK.

A comparative study of visual quality between implantable collamer lens implantation and femtosecond LASIK for myopia

Background The incidence of myopia is gradually increasing, and how to choose a better corrective method of myopia for the best visual demand is very important. Objective This study was to compare visual quality of implantable collamer lens (ICL) implantation with femtosecond laser in situ keratomileusis (FS-LASIK) for moderate and high myopia using double-pass optical quality analysis system (OQAS). Methods A non-randomized controlled clinical trail was performed.Fifty-two eyes with -4.00 to -9.00 D of 26 consecutive patients were included in NO.1 Hospital of Xi'an from January 2015 to January 2016.Twenty-four eyes of 12 patients with the corneal thickness 0.05). All the patients were followed-up for 3 months after surgery.The preoperative best corrected distance visual acuity (BCDVA), spherical equivalent (SE), postoperative uncorrected distance visual acuity (UCDVA), BCDVA and SE were examined and compared between two groups.The parameters from OQAS were evaluated and intergrouply compared, including the objective scattering inders (OSI), modulation transfer function (MTF) cut off frequency, Strehl ratio and OQAS values under the contrast of 100%, 20% and 9%(OV100, OV20, OV9). Results The postoperative BCDVA was not significantly different from preoperative UCDVA in both ICL group and FS-LASIK group (-0.04±0.10 vs. 0.05±0.12; -0.07±0.12 vs.0.00±0.12) (t=3.128, 2.358, both at P>0.05). No statistically significant differnces were found in SE, UCDVA and BCDVA after operation between ICL group and FS-LASIK group (t=1.292, 0.900, -0.653, all at P>0.05). OQAS examination showed that MTF cut off, OSI, Strehl ratio, OV100 were not significantly different after operation between ICL group and FS-LASIK group (t=-2.032, -1.440, -0.224, all at P>0.05). The postoperative OV20 and OV9 were 0.82±0.14 and 0.80±0.21 in the ICL group, which were significantly higher than those in the FS-LASIK group(0.59±0.15 and 0.47±0.13)(t=4.105, 4.702, both at P<0.05). Conclusions Both ICL implantation and FS-LASIK provide good optical and visual quality for moderate to high myopic eyes, and ICL appears to have a better visual quality in comparison with FS-LASIK under the contrasts of 20% and 9%. Key words: Myopia/surgery; Refractive surgical procedure; Phakic intraocular lenses; Keratomileusis, laser in situ; Visual quality; Implantable collamer lens; Double-pass optical quality analysis system

Confocal Comparison of Corneal Reinnervation after Small Incision Lenticule Extraction (SMILE) and Femtosecond Laser In Situ Keratomileusis (FS-LASIK)

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.

Femtosecond laser in situ keratomileusis versus conductive keratoplasty to obtain monovision in patients with emmetropic presbyopia

To compare visual outcomes, complications, and patient satisfaction after femtosecond laser in situ keratomileusis (LASIK) and conductive keratoplasty (CK). Private laser clinics, Reading and Southampton, United Kingdom. In this retrospective consecutive single-surgeon comparative study, presbyopic emmetropia was treated with femtosecond LASIK or CK to achieve monovision by targeting -1.50 diopters (D) of myopia in the nondominant eye after a successful monovision contact lens trial. The CK treatments were performed with a ViewPoint CK system using the light-touch technique. The femtosecond LASIK was performed using an IntraLase FS/FS30 and EC-5000 platform with OPDCAT wavefront treatment. The mean spherical equivalent 12 months postoperatively was -1.63 D +/- 0.68 (SD) in the femtosecond LASIK group and -0.97 +/- 0.82 D in the CK group (P<.001). The mean vector value of astigmatism at 12 months was 0.32 +/- 0.32 D and 1.00 +/- 0.75 D, respectively (P<.0001). The mean induced higher-order aberration (HOA) was 0.45 +/- 0.28 microm in the femtosecond LASIK group and 1.13 +/- 0.25 microm in the CK group (P<.0001). The retreatment rate was 3% after femtosecond LASIK and 50% after CK (P<.0001). On a questionnaire administered at 12 months, 20 patients (62.5%) in the femtosecond LASIK group and 11 patients (34.4%) in the CK group reported being satisfied (P = .02). In emmetropic presbyopic cases, femtosecond LASIK monovision provided stable correction with less induced astigmatism and HOA. Eyes with CK monovision had regression and induced astigmatism.

Measurement of corneal curvature change after mechanical laser in situ keratomileusis flap creation and femtosecond laser flap creation

To compare the change in corneal curvature from the predicted surgical radius (sculpted in the corneal stroma) and the measured postoperative radius of the first surface of the cornea after laser in situ keratomileusis (LASIK) for myopia correction using 2 methods of flap creation: mechanical microkeratome and femtosecond laser. Vissum-Instituto Oftalmológico de Alicante, Alicante, Spain. This retrospective consecutive nonrandomized comparative interventional case series included 85 eyes with myopia or myopic astigmatism treated using the Esiris excimer laser (Schwind). Patients were divided into 2 groups. One group had LASIK with an M2 microkeratome (Moria) (mechanical LASIK group) and the other, with a femtosecond laser (IntraLase FS, IntraLase Corp.) (femtosecond LASIK group). The relationship between the postsurgical corneal radius and the predicted sculpted radius as well as the mean value of the percentage change in the curvature radius were analyzed to obtain the effect on the refractive defect in each group. There were 44 eyes in the mechanical LASIK group and 41 eyes in the femtosecond LASIK group. A high correlation was found between the final corneal radius and the predicted sculpted radius in both groups (r(2) = 0.85). The mean percentage change in the curvature radius was -3.6% in the mechanical LASIK group and -1.6% in the femtosecond LASIK group (P<.001). The mean estimated refractive change was 1.2 diopters (D) and 0.8 D, respectively. The refractive change in corneal curvature, which related to the biomechanical response of the corneal surface after the flap cut and repositioning, was lower after femtosecond laser LASIK than after LASIK performed using a mechanical microkeratome. Estimations of refractive change induced by this response should be taken into account in surgery design.