Effect of sample temperature on femtosecond laser ablation of copper

We conduct an experimental study supported by theoretical analysis of single laser ablating copper to investigate the interactions between laser and material at different sample temperatures,and predict the changes of ablation morphology and lattice temperature.For investigating the effect of sample temperature on femtosecond laser processing,we conduct experiments on and simulate the thermal behavior of femtosecond laser irradiating copper by using a two-temperature model.The simulation results show that both electron peak temperature and the relaxation time needed to reach equilibrium increase as initial sample temperature rises.When the sample temperature rises from 300 K to 600 K,the maximum lattice temperature of the copper surface increases by about 6500 K under femtosecond laser irradiation,and the ablation depth increases by 20%.The simulated ablation depths follow the same general trend as the experimental values.This work provides some theoretical basis and technical support for developing femtosecond laser processing in the field of metal materials.

Clinical efficacy of femtosecond laser-assisted phacoemulsification in diabetic cataract patients

BACKGROUND Diabetic patients with cataracts encounter specific difficulties during cataract surgery due to alterations in microcirculation,blood supply,metabolism,and the microenvironment.Traditional phacoemulsification may not fully tackle these issues,especially in instances with substantial preoperative astigmatism.The utilization of femtosecond laser-assisted phacoemulsification,in conjunction with Toric intraocular lens(IOL)implantation,offers a potentially more efficient strategy.This research seeks to evaluate the efficacy and possible complications of this approach in diabetic cataract patients.AIM To investigate the clinical efficacy and complications of femtosecond laser-assisted phacoemulsification combined with Toric IOL implantation in diabetic cataract patients,comparing it with traditional phacoemulsification methods.METHODS This retrospective study enrolled 120 patients with diabetes cataract from May 2019 to May 2021.The patients were divided into two groups:the control group underwent traditional phacoemulsification and Toric IOL implantation,while the treatment group received Len Sx femtosecond laser-assisted treatment.Outcome measures included naked eye vision,astigmatism,high-level ocular phase difference detection,clinical efficacy,and complication.RESULTS There were no significant preoperative differences in astigmatism or naked eyesight between the two groups.However,postoperative improvements were observed in both groups,with the treatment group showing greater enhancements in naked eye vision and astigmatism six months after the procedure.High-level corneal phase difference tests also indicated significant differences in favor of the treatment group.CONCLUSION This study suggests that femtosecond laser-assisted phacoemulsification combined with Toric IOL implantation appears to be more effective in enhancing postoperative vision in diabetic cataract patients compared to traditional methods offering valuable insights for clinical practice.

Evaluation of the Clinical Efficacy of Full Femtosecond Laser Surgery in the Treatment of Myopia

Objective:To evaluate the clinical effect of full femtosecond laser surgery in the treatment of myopia patients.Methods:120 myopia patients admitted to our hospital from January 2022 to June 2023 were selected.According to the random number table method,60 patients in the observation group underwent full femtosecond laser surgery,and 60 patients in the control group underwent femtosecond laser-assisted in situ keratomileusis(FS-LASIK)surgery.The clinical effects of the two groups were compared.Results:10 days postoperatively and 6 months after operation,the visual acuity level of the observation group was higher than that of the control group,the postoperative corneal asphericity coefficient and corneal full-thickness were lower than those of the control group,and the total effective rate 6 months after operation was higher than that of the control group(P<0.05).Conclusion:Full femtosecond laser surgical treatment can improve the postoperative visual acuity of patients with myopia,enhance the corneal asphericity coefficient(Q)and corneal full-thickness,and exert significant clinical effects.

Corneal astigmatic outcomes after femtosecond laser-assisted cataract surgery combined with surface penetrating arcuate keratotomies

AIM:To evaluate corneal astigmatic outcomes of femtosecond laser-assisted arcuate keratotomies(FAKs)combined with femtosecond-laser assisted cataract surgery(FLACS)over 12mo follow-up.METHODS:Totally 145 patients with bilateral cataracts and no ocular co-morbidities were recruited to a singlecentre,single-masked,prospective randomized controlled trial(RCT)comparing two monofocal hydrophobic acrylic intraocular lenses.Eyes with corneal astigmatism(CA)of>0.8 dioptres(D)received unpaired,unopened,surface penetrating FAKs at the time of FLACS.Visual acuity,subjective refraction and Scheimpflug tomography were recorded at 1,6,and 12mo.Alpins vectoral analyses were performed.RESULTS:Fifty-one patients(61 eyes),mean age 68.2±9.6y[standard deviation(SD)],received FAKs.Sixty eyes were available for analysis,except at 12mo when 59 attended.There were no complications due to FAKs.Mean pre-operative CA was 1.13±0.20 D.There was a reduction of astigmatism at all post-operative visits(residual CA 1mo:0.85±0.42 D,P=0.0001;6mo:0.86±0.35 D,P=0001;and 12mo:0.90±0.39,P=0.0001).Alpins indices remained stable over 12mo.Overall,the cohort was under-corrected at all time points.At 12mo,61%of eyes were within±15 degrees of pre-operative astigmatic meridian.CONCLUSION:Unpaired unopened penetrating FAKs combined with on-axis phacoemulsification are safe but minimally effective.CA is largely under-corrected in this cohort using an existing unmodified nomogram.The effect of arcuate keratotomies on CA remained stable over 12mo.

Microsphere femtosecond laser sub-50 nm structuring in far field via non-linear absorption

Creation of arbitrary features with high resolution is critically important in the fabrication of nano-optoelectronic devices.Here,sub-50 nm surface structuring is achieved directly on Sb2S3 thin films via microsphere femtosecond laser irradi-ation in far field.By varying laser fluence and scanning speed,nano-feature sizes can be flexibly tuned.Such small patterns are attributed to the co-effect of microsphere focusing,two-photons absorption,top threshold effect,and high-repetition-rate femtosecond laser-induced incubation effect.The minimum feature size can be reduced down to~30 nm(λ/26)by manipulating film thickness.The fitting analysis between the ablation width and depth predicts that the feature size can be down to~15 nm at the film thickness of~10 nm.A nano-grating is fabricated,which demonstrates desirable beam diffraction performance.This nano-scale resolution would be highly attractive for next-generation laser nano-lithography in far field and in ambient air.

Crack-free high-aspect ratio holes in glasses by top–down percussion drilling with infrared femtosecond laser GHz-bursts

We report novel results on top-down percussion drilling in different glasses with femtosecond laser GHz-bursts.Thanks to this particular regime of light–matter interaction,combining non-linear absorption and thermal cumulative effects,we obtained crack-free holes of aspect ratios exceeding 30 in sodalime and 70 in fused silica.The results are discussed in terms of inner wall morphology,aspect ratio and drilling speed.

Periodic transparent nanowires in ITO film fabricated via femtosecond laser direct writing

This paper reports the fabrication of regular large-area laser-induced periodic surface structures(LIPSSs)in indium tin oxide(ITO)films via femtosecond laser direct writing focused by a cylindrical lens.The regular LIPSSs exhibited good properties as nanowires,with a resistivity almost equal to that of the initial ITO film.By changing the laser fluence,the nanowire resistances could be tuned from 15 to 73 kΩ/mm with a consistency of±10%.Furthermore,the average transmittance of the ITO films with regular LIPSSs in the range of 1200-2000 nm was improved from 21%to 60%.The regular LIPSS is promising for transparent electrodes of nano-optoelectronic devices-particularly in the near-infrared band.

Femtosecond laser direct writing of functional stimulus-responsive structures and applications

Diverse natural organisms possess stimulus-responsive structures to adapt to the surrounding environment.Inspired by nature,researchers have developed various smart stimulus-responsive structures with adjustable properties and functions to address the demands of ever-changing application environments that are becoming more intricate.Among many fabrication methods for stimulus-responsive structures,femtosecond laser direct writing(FsLDW)has received increasing attention because of its high precision,simplicity,true three-dimensional machining ability,and wide applicability to almost all materials.This paper systematically outlines state-of-the-art research on stimulus-responsive structures prepared by FsLDW.Based on the introduction of femtosecond laser-matter interaction and mainstream FsLDW-based manufacturing strategies,different stimulating factors that can trigger structural responses of prepared intelligent structures,such as magnetic field,light,temperature,pH,and humidity,are emphatically summarized.Various applications of functional structures with stimuli-responsive dynamic behaviors fabricated by FsLDW,as well as the present obstacles and forthcoming development opportunities,are discussed.

Hot electron electrochemistry at silver activated by femtosecond laser pulses

A silver microelectrode with a diameter of 30μm in an aqueous K_(2)SO_(4) electrolyte was irradiated with 55 fs and 213 fs laser pulses.This caused the emission of electrons which transiently charged the electrochemical double layer.The two applied pulse durations were significantly shorter than the electron-phonon relaxation time.The laser pulse durations had negligible impact on the emitted charge,which is incompatible with multiphoton emission.On the other hand,the ob-served dependence of emitted charge on laser fluence and electrode potential supports the thermionic emission mechanism.

High power,widely tunable femtosecond MgO:PPLN optical parametric oscillator

We demonstrate a high power,widely tunable femtosecond MgO-doped periodically poled lithium niobate(MgO:PPLN)optical parametric oscillator(OPO)at 151 MHz,pumped by a Kerr-lens mode-locked Yb:KGW laser.With a maximum pump power of 7 W,the OPO is capable of delivering as high as 2.2 W of the signal centered around 1500 nm with tunable signal spectrum ranges of 1377 nm-1730 nm at an extraction efficiency of 31.4%,which exhibits a long-term passive power stability better than 0.71%rms over 4 h.The maximum idler bandwidths of 185 nm at 3613 nm are obtained across the idler tuning ranges of 2539 nm-4191 nm.By compensating intracavity dispersion,the signal has the shortest pulse duration of 170 fs at 1428 nm.

Application of femtosecond laser in assisted cataract after ICL implantation with different vault

Dear Editor,We are writing this letter to report two unusual cases of femtosecond laser-assisted cataract surgery(FLACS)in two ICL-implanted patients with significant different vault.FLACS has been confirmed by accumulating evidence to improve the safety and precision of surgery from common cases to complicated cases in treating cataracts[1-3].Implantable collamer lens(ICL)implantation possesses a good performance in its predictability,reversibility,and the rapid visual recovery.

Symmetrical femtosecond laser arc incision in correcting corneal astigmatism in cataract patients

AIM:To evaluate the effect of symmetrical arc incision correcting corneal astigmatism in femtosecond laserassisted phacoemulsification(FLACS).METHODS:This study enrolled patients with cataract combined with regular corneal astigmatism of>0.75 D,who underwent FLACS.Symmetrical arc incision was set at 8 mm diameter and 85%depth.The follow-up time was 3-24mo(4.92±3.49mo).Pentacam recorded the corneal astigmatism and higher-order aberration at pre-operation and post-operation.The changes in corneal astigmatism were analyzed by Alpins method.The correlation of astigmatism type,age,corneal horizontal diameter,corneal thickness,arc incision length,and correction index(CI)was analyzed,and the residual corneal astigmatism was compared with the residual whole eye astigmatism.RESULTS:Totally 79 patients(102 eyes)were enrolled,10 patients had corneal epithelial injury,1 patient occurred corneal epithelial hyperplasia.The corneal astigmatism was 1.23±0.38 D pre-operation,and decreased to 0.76±0.39 D post-operation(t=10.146,P=0.000).Corneal high-order aberration was 0.17±0.08μm pre-operation and 0.24±0.11μm post-operation(t=-5.186,P=0.000).The residual corneal astigmatism and residual whole eye astigmatism were no significant difference(t=-0.347,P=0.729).Using Alpin’s method,the following were determined:target-induced astigmatism(TIA)=1.23±0.38 D,surgeryinduced astigmatism(SIA)=0.77±0.45 D,difference vector(DV)=0.77±0.39 D,and CI=0.54±0.28.Age,astigmatism size,corneal horizontal diameter,corneal thickness,and arc incision length were not correlated with CI.The CI for against the rule astigmatism(ATR)was better than that for with the rule astigmatism(WTR;P=0.001).CONCLUSION:Femtosecond laser-assisted astigmatic keratotomy has better CI of ATR,but increase higher-order corneal aberration.CI is not ideal,it’s not a perfect choice if we pursue ideal correction effect.

Comparison of visual performance with iTrace analyzer following femtosecond laser-assisted cataract surgery with bilateral implantation of two different trifocal intraocular lenses

AIM:To compare the postoperative binocular visual performance with an iTrace analyzer following femtosecond laser-assisted cataract surgery(FLACS)combined with bilateral implantation of two different types of diffractive trifocal intraocular lenses(IOL).METHODS:During this retrospective observational study,patients who received bilateral FLACS combined with implantation of two different types of diffractive trifocal IOLs were evaluated.According to the IOLs’different types and design,the patients were divided into AT LISA tri839MP group(tri839 group)and AcrySof PanOptix TFNT00 group(TFNT group).Study parameters included preoperative and postoperative uncorrected distance visual acuity(UDVA)at 5 m,uncorrected near visual acuity(UNVA)at 30 cm and 40 cm,uncorrected intermediate visual acuity(UIVA)at 60 cm and 80 cm,postoperative refractive status,objective visual qualities and total high order aberrations(HOAs)postoperatively.The postoperative complications were also recorded.RESULTS:Totally 56 eyes of 28 patients(tri839 group,n=26;TFNT group,n=30)were included.Preoperative baseline characteristics between groups were not statistically significantly different.UDVA was not significantly different between groups except for 1wk follow-up due to the postoperative corneal edema.TFNT group showed statistically significant better UNIA at 60 cm than tri839 group at the 1wk(0.05±0.19 vs 0.15±0.10 logMAR,P=0.013),1mo(0.05±0.12 vs 0.15±0.09 logMAR,P=0.001)and 3mo(0.04±0.12 vs 0.15±0.11 logMAR,P=0.001)follow-up,while tri839 group showed statistically significant better UNIA at 80 cm than TFNT group at the 1d(0.14±0.15 vs 0.20±0.14 logMAR,P=0.041)and 1mo(0.09±0.07 vs 0.14±0.10 logMAR,P=0.042)follow-up.Postoperative refractive status showed stable at every visit.Modulated transfer function(MTF)values and strehl ratio(SR)values were improved and HOAs were lower significantly after surgery.CONCLUSION:FLACS with bilateral implantations of both tri839 and TFNT00 can achieve satisfactory natural whole-course vision,high postoperative refractive stability and good visual quality but without significantly difference.iTrace aberration instrument can accurately evaluate the visual quality under different status.

Numerical Simulation for the Efficiency of the Produced Terahertz Radiation by Two Femtosecond Laser Pulses: Above-Threshold-Ionization

The tunneling ionization (TI) is the most dominated ionization process in the production of terahertz radiation by two femtosecond lasers, although its validity above the ionization threshold of some gases is uncertain. In the present research, we employ a 1D fluid code to simulate the efficiency of the produced terahertz radiation by two femtosecond laser beams in air plasma. Two ionization models in the context of the TI process which are the Ammosov-Delone-Krainov (ADK) for noble gases and its developed molecular ADK (MO-ADK) model for molecular gases are intrinsically used to conduct this study. The main target of the present research is to examine the validity of these models Above-Threshold-Ionization (ATI) of these gases. For this purpose, we simulated the ionization rate and the power spectrum of the produced radiation, in addition we numerically evaluated the efficiency of the produced radiation as function of the input beams intensity at particular energy fraction factor, relative phase and initial pulse duration of these beams. These calculations conducted for a selected noble gas at varying energy levels and a chosen molecular air plasma gas at different quantum numbers. Numerical results near and above the ionization threshold of the selected gases have clarified that the ADK and MO-ADK model are successful valid to study the efficiency of the produced THz radiation at low energy levels and small quantum numbers of the selected gases, meanwhile, with any further increase in the energy level and the quantum number values of these gases, both of the ADK and MO-ADK are failed to correctly analyze the efficiency process and estimate its fundamental parameters.

Three-year results of small incision lenticule extraction and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis for correction of high myopia and myopic astigmatism

AIM： To compare and calculate the 3-year refractive results, higher-order aberrations （HOAs）, contrast sensitivity （CS） and dry eye parameters after small incision lenticule extraction （SMILE） and wavefront-guided femtosecond laser-assisted laser in situ keratomileusis （FS-LASIK） for correction of high myopia and myopic astigmatism. METHODS： In this prospective, non-randomized comparative study, 78 eyes with spherical equivalent （SE） of -8.11±1.09 diopters （D） received a SMILE surgery, and 65 eyes with SE of -8.05±1.12 D received a wavefront-guided FS-LASIK surgery with the VisuMax femtosecond laser （Carl Zeiss Meditec, Jena, Germany） for flap cutting. Visual acuity, manifest refraction, CS, HOAs, ocular surface disease index （OSDI） and tear break-up time （TBUT） were evaluated during a 3-year follow-up. RESULTS： The difference of uncorrected distance visual acuity （UDVA） postoperatively was achieved at lmo and at 3mo, whereas the difference of the mean UDVA between two groups at 3y were not statistically significant （t=-1.59, P=-0.13）. The postoperative change of SE was 0.89 D in the FS-LASIK group （t=5.76, P=0.00）, and 0.14 D in the SMILE group （t=-0.54, P=0.59） from lmo to 3y after surgery. At 3-year postoperatively, both HOAs and spherical aberrations in the SMILE group were obviously less than those in the FS-LASIK group （P=0.00）, but the coma root mean square （RMS） was higher in the SMILE group （0.59±0.26） than in the FS-LASIK group （0.29±0.14, P=0.00）. The mesopic CS values between two groups were not statistically significant at 3y postoperatively. Compared with the FS-LASIK group, lower OSDI scores and longer TBUT values were found in the SMILE group at Imo and 3mo postoperatively. With regard to safety, no eye lost any line of CDVA in both groups at 3y after surgery. CONCLUSION： Both SMILE and wavefront-guided FS- LASIK procedures provide good visual outcomes. Both procedures are effective and safe, but SMILE surgery achieve more stable long-term refractive outcome and better control of early postoperative dry eye as compared to FS-LASIK.

Determination of Iron in Water Solution by Time-Resolved Femtosecond Laser-Induced Breakdown Spectroscopy

The influence of the energy of femtosecond laser pulses on the intensity of Fe I （371.99 nm） emission line and the continuous spectrum of the plasma generated on the surface of Fe^3＋ water solution by a Ti： sapphire laser radiation with pulse duration 〈45 fs and energies up to 7 mJ is determined. A calibration curve was obtained for Fe3＋ concentration range from 0.5 g/L to the limit of detection in water solution, and its saturation was detected for concentrations above 0.25 g/L, which is ascribed to self-absorption. The 3σ- limit of detection obtained for Fe in water solution is 2.6 mg/L in the case of 7 mJ laser pulse energy. It is found that an increase of laser pulse energy insignificantly affects on LOD in the time-resolved LIBS and leads to a slight improvement of the limit of detection.

Comparison of early changes in ocular surface markers and tear inflammatory mediators after femtosecond lenticule extraction and FS-LASIK

AIM:To compare the short-term impacts of femtosecond lenticule extraction(FLEx)and femtosecond laser-assisted laser in situ keratomileusis(FS-LASIK)on ocular surface measures and tear inflammatory mediators.METHODS:This prospective comparative nonrandomized clinical study comprised 75 eyes(75 patients).Totally 20 male and 15 female patients(age 21.62±3.25 y)with 35 eyes underwent FLEx,and 26 male and 14 female patients(age 20.18±3.59 y)with 40 eyes underwent FS-LASIK.Central corneal sensitivity,noninvasive tear breakup time,corneal fluorescein staining,Schirmer I test,tear meniscus height,and ocular surface disease index were evaluated in all patients.Tear concentrations of nerve growth factor(NGF),interleukin-1α(IL-1α),transforming growth factor-β1(TGF-β1),tumor necrosis factor-α(TNF-α),interferon-γ(IFN-γ),and matrix metalloproteinase-9(MMP-9)were assessed by multiplex antibody microarray.All measurements were performed preoperatively,and 1 d,1 wk,and 1 mo postoperatively.RESULTS:Patients who underwent FLEx exhibited a more moderate reduction in central corneal sensation and less corneal fluorescein staining than those in the FS-LASIK group 1 wk after the procedure(P<0.01).NGF was significantly higher 1 d and 1 wk after surgery in the FS-LASIK group than in the FLEx group(P<0.01).By contrast,compared to those in the FLEx group,higher postoperative values and slower recovery of tear TGF-β1,IL-1α,and TNF-αconcentrations were observed in the FS-LASIK group(P<0.01).Tear concentrations of NGF,TGF-β1,TNF-α,and IL-1αwere correlated with ocular surface changes after FLEx or FS-LASIK surgery.CONCLUSION:There is less early ocular surface disruption and a reduced inflammatory response after FLEx than after FS-LASIK.NGF,TGF-β1,TNF-α,and IL-1αmay contribute to the process of ocular surface recovery.

Case report:simultaneous femtosecond laser astigmatic keratotomy and toric intraocular lens implantation in femtosecond laser-assisted cataract surgery in a patient with surgically induced high corneal astigmatism

Background:Femtosecond laser astigmatic keratotomy(FSAK)and toric intraocular lens(IOL)implantation have been studied individually for comparison to treat astigmatism at cataract surgery.We report a case of surgically induced high corneal astigmatism by laser thermal keratoplasty(LTK)in a patient with cataract who was successfully treated with simultaneous combination of FSAK and toric IOL implantation with femtosecond laser-assisted cataract surgery(FLACS).This is the first report of both procedures combined simultaneously,with or without history of LTK.Case Description:A 68-year-old male presented with a history of LTK with two enhancements each eye in 2004,with subsequent surgically induced high corneal astigmatism,and with age-related nuclear cataract of both eyes.IOL master demonstrated+7.71 diopters of astigmatism at 163 degree right eye and+3.29 diopters of astigmatism at 4 degree left eye.After extensive discussion of the risks and benefits,the patient agreed to undergo FLACS with FSAK with two 61 degrees of relaxation incisions(RIs)and toric IOL(Alcon SN6AT9)right eye;FLACS with toric IOL(Alcon SN6AT7)alone left eye.At 2-year follow-up,uncorrected visual acuity was 20/30 right eye,20/25 left eye.His best corrected visual acuity was 20/25(+0.25+1.00 axis 21)right eye and 20/20(plano+0.25 axis 90)left eye;his best corrected near visual acuity was J1+with add+2.50 diopters right eye and left eye.Conclusions:Patients with age-related cataract and LTK induced high corneal astigmatism can hardly be sufficiently treated with FSAK or toric IOL alone at the time of cataract surgery.An effective way is to combine large FSAK and toric IOL of the highest cylindrical power of T9,in our case,simultaneously,which can achieve an excellent long term visual outcome.

Comparing the intraoperative complication rate of femtosecond laser-assisted cataract surgery to traditional phacoemulsification

AIM: To compare the complication rate of femtosecond laser-assisted cataract surgery(FLACS) and traditional phacoemulsification for the first 18 mo of FLACS use at a private surgical center in Hawaii.METHODS: A retrospective chart review was conducted from January 2012 to June 2013. The first 273 consecutive eyes receiving FLACS and 553 eyes receiving traditional phacoemulsification were examined.All surgeries were performed at a single surgical center in Hawaii. The presence of intraoperative complications was used as the main outcome measure. Approval was obtained from the institutional review board of the University of Hawaii.RESULTS: The overall complication rate for FLACS was 1.8%, while that of the traditional procedure was5.8%(P 【0.05). A majority of the surgeons(80%) had a lower complication rate while using FLACS.CONCLUSION: FLACS is comparable in safety, if not safer, than traditional cataract surgery when performed by qualified cataract surgeons on carefully selected patients.

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

AIM：To evaluate the possible differences in visual quality between small incision lenticule extraction（SMILE）and femtosecond laser in situ keratomileusis（FS-LASIK）for myopia.METHODS：A Meta-analysis was performed.Patients were from previously reported comparative studies treated with SMILE versus FS-LASIK.The Pub Med,EMBASE,Cochrane,Web of Science and Chinese databases（i.e.WANFANG and CNKI）were searched in Nov.of 2016 using Rev Man 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.RESULTS：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 20/20or better（P=0.43）,the final refractive spherical equivalent（P=0.89）,the refractive spherical equivalent within±1.00diopter of the target values（P=0.80）,vertical coma（P=0.45）and horizontal coma（P=0.06）.Compared with the FSLASIK 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.CONCLUSION：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.