Ten-year observation of corneal densitometry and associated factors following small incision lenticule extraction

●AIM:To investigate the long-term changes of corneal densitometry(CD)and its contributing elements after small incision lenticule extraction(SMILE).●METHODS:Totally 31 eyes of 31 patients with mean spherical equivalent of-6.46±1.50 D and mean age 28.23±7.38y were enrolled.Full-scale examinations were conducted on all patients preoperatively and during followup.Visual acuity,manifest refraction,axial length,corneal thickness,corneal higher-order aberrations,and CD were evaluated.●RESULTS:All surgeries were completed successfully without complications or adverse events.Ten-year safety index was 1.17±0.20 and efficacy 1.04±0.28.CD value of 0–6 mm zones in central layer was statistically significantly lower 10y postoperatively,compared with preoperative values(0–2 mmΔ=-1.62,2–6 mmΔ=-1.24,P<0.01).There were no correlations between CD values and factors evaluated.●CONCLUSION:SMILE is a safe and efficient procedure for myopia on a long-term basis.CD values get lower 10y postoperatively,whose mechanism is to be further discussed.

Changes in posterior corneal elevation after small incision lenticule extraction for different myopic diopters

●AIM:To study the changes and effect factors of posterior corneal surface after small incision lenticule extraction(SMILE)with different myopic diopters.●METHODS:Ninety eyes of 90 patients who underwent SMILE were included in this retrospective study.Patients were allocated into three groups based on the preoperative spherical equivalent(SE):low myopia(SE≥-3.00 D),moderate myopia(-3.00 D>SE>-6.00 D)and high myopia(SE≤-6.00 D).Posterior corneal surfaces were measured by a Scheimpflug camera preoperatively and different postoperative times(1wk,1,3,6mo,and 1y).Posterior mean elevation(PME)at 25 predetermined points of 3 concentric circles(2-,4-,and 6-mm diameter)above the best fit sphere was analyzed.●RESULTS:All surgeries were completed uneventfully and no ectasia was found through the observation.The difference of myopia group was significant at the 2-mm ring at 1 and 3mo postoperatively(1mo:P=0.017;3mo:P=0.018).The effect of time onΔPME was statistically significant(2-mm ring:P=0.001;4-mm ring:P<0.001;6-mm ring:P<0.001).The effect of different corneal locations onΔPME was significant except 1wk postoperatively(1mo:P=0.000;3mo:P=0.000;6mo:P=0.001;1y:P=0.001).Posterior corneal stability was linearly correlated with SE,central corneal thickness,ablation depth,residual bed thickness,percent ablation depth and percent stromal bed thickness.●CONCLUSION:The posterior corneal surface changes dynamically after SMILE.No protrusion is observed on the posterior corneal surface in patients with different degrees of myopia within one year after surgery.SMILE has good stability,accuracy,safety and predictability.

Analysis of Ultrasonic Emulsification Surgery and Small Incision Cataract Extracapsular Extraction Surgery for Cataract Clinical Treatment Level Improvement

Objective:To analyze the efficacy of ultrasonic emulsification and small incision cataract extracapsular extraction in cataract patients.Methods:96 cataract patients admitted from May 2021 to May 2023 were selected and randomly grouped into group A(ultrasonic emulsification)and group B(small-incision extracapsular cataract extraction),with 48 cases each.Results:At 1 week,1-month,and 3 months post-operation,the visual acuity of group A was higher and the astigmatism value was lower than that of group B(P<0.05);at 12h,24h,and 48h post-operation,the intraocular pressure of group A was higher than that of group B(P<0.05);the thickness of macular area of group A was lower than that of group B at 1 week and 1-month post-operation(P<0.05).Conclusion:Ultrasonic emulsification in cataract patients was slightly better than small incision cataract extracapsular extraction in correcting astigmatism,improving visual acuity,and regulating macular thickness.However,due to the high energy of ultrasonic emulsification,the risk of complications such as high postoperative intraocular pressure was higher.Small-incision extracapsular cataract extraction has better application value in economically disadvantaged areas.

Postoperative efficacy,safety,predictability,and visual quality of implantable collamer lens implantation versus small incision lenticule extraction in myopic eyes:a Meta-analysis

AIM:To compare the postoperative efficacy,safety,predictability,and visual quality of implantable collamer lens(ICL)implantation versus small incision lenticule extraction(SMILE)in myopia eyes.METHODS:Pub Med,EMBASE,Web of Science,Cochrane Library and several Chinese databases were searched at May 2021 to select relevant studies in comparison of clinical outcomes between ICL implantation and SMILE for myopia.The primary outcomes were efficacy,safety,and predictability.And the secondary outcomes were postoperative higher-order ocular aberrations(HOAs),modulation transfer function cutoff frequency(MTF),objective scatter index(OSI),contrast sensitivity and a quality of vision(Qo V)questionnaire.RESULTS:A total of 1036 eyes from 10 studies,of which 503 eyes underwent ICL implantation and 533 eyes underwent SMILE,were enrolled in this Meta-analysis.Pooled results revealed that ICL group had a better safety index and post-corrected distance visual acuity(CDVA)(P=0.007,<0.00001,respectively),and a lower percentage of eyes with a postoperative CDVA lost 1 line(P=0.007)than the SMILE group.No significant differences were found in comparison of the other primary outcomes.In the longterm follow-up(>6mo),ICL group had a lower total HOA,coma,and spherical aberration than SMILE group(P=0.003,<0.00001,0.04).Yet higher trefoil was found in ICL group at 6mo after surgery(P=0.003).Additionally,ICL group also had a higher MTF value(P=0.02),and a higher contrast sensitivity score for spatial frequencies of 1.5,6,and 12 cpds(P=0.02,0.005,0.02,respectively).And it also had a lower score of bothersome in Qo V questionnaire than SMILE group(P=0.003).CONCLUSION:ICL implantation and SMILE have similar and comparable outcomes in term of the efficacy and predictability for correcting high myopia.However,ICL group is relatively safer and also has better visual quality in comparison of SMILE group.

Small incision lenticule extraction and femtosecond-assisted laser in situ keratomileusis in patients with deep corneal opacity:case series

AIM:To report the safety,efficacy,and accuracy of small-incision lenticule extraction(SMILE)or femtosecondassisted laser in situ keratomileusis(FS-LASIK)for the correction of myopia or myopic astigmatism in patients with deep corneal opacity denoted by anterior segment optical coherence tomography(AS-OCT).METHODS:Four patients with monocular corneal opacity(3 due to mechanical injury,1 due to a firecracker wound)were recruited and treated with refractive surgery(3 for SMILE,1 for FS-LASIK combined with limbal relaxing incision(LRI).Preoperative ocular manifestations,surgical details,postoperative visual outcomes,corneal opacity parameters,and corneal topography were analyzed.RESULTS:Preoperatively,spherical diopter ranged from-3.0 D to-4.75 D with cylinder ranging from-0.75 to-5.0 D,and corrected distance visual acuity(CDVA)ranging from 20/25 to 20/20.One eye’s corneal opacity was located in the central zone and three were in the mid-peripheral optical zone.Three patients underwent uneventful SMILE in both eyes,whilst one patient underwent FS-LASIK for high astigmatism in both eyes and LRI in the right eye.CDVA of the eye with corneal opacity ranged from 20/22to 20/20 one to six weeks postoperatively.Two patients achieved better CDVA and no patients lost Snellen lines.The postoperative diopter was within±0.75 D for all eyes.Significant edema existed above the corneal opacity in one eye and dissipated soon.No eccentric corneal topography or morphological anomaly of the corneal cap or flap was observed.CONCLUSION:The cases demonstrate that SMILE or FS-LASIK is safe and effective to treat myopic astigmatism combined with deep corneal opacity lesions after comprehensive preoperative evaluation and appropriate candidate selection.FS-LASIK combined with LRI is also sufficient for correcting high astigmatism due to corneal scarring.

Effectiveness and the nomogram of small incision lenticule extraction in the correction of myopic anisometropia in adults

AIM:To evaluate the safety,effectiveness,and predictability of small incision lenticule extraction(SMILE)for the treatment of anisometropia,and to explore the personalized design scheme of SMILE in correcting adult myopia anisometropia based on the nomogram.METHODS:It’s a prospective cohort study.Patients with anisometropic myopia of refractive difference≥2.0 diopters(D)who underwent SMILE between September 2020 and March 2021 were enrolled.Clinical features and visual function were assessed preoperatively and at 1wk,1,3,and 6mo after the operation.The examination included tests for uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),refractive errors,effectiveness index(preoperative CDVA/postoperative UDVA),safety index(postoperative CDVA/preoperative CDVA),nomogram and stereoscopic function.Paired t-test,Wilcoxon signed-rank test and repeated-measures analyses of variance were used for continuous variables,and Pearson Chi-squared test was used for categorical variables.RESULTS:The study involved 45 consecutive patients(average age:25.0±6.9y;82 out of 90 eyes underwent SMILE,while 8 eyes were not operated).The average preoperative spherical equivalent(SE)was-4.74±0.22 D.Six months after surgery,the effectiveness index was 1.05±0.12,and the safety index was 1.09±0.11.Seventy eyes(85.4%)exhibited SE correction error within±0.5 D.The percentage of eyes with Titmus stereoscopic function equal to or less than 200”significantly increased from 55.6%preoperatively to 88.9%postoperatively(P<0.05).There was statistically significant difference between higher myopia eyes and contralateral eyes in average nomogram value/spherical refraction ratio.CONCLUSION:SMILE is safe,effective and predictable in correcting myopic anisometropia,and it improves stereoscopic visual function of anisometropia patients.The precise and individualized design of the nomogram is a vital element to ensure the balance of both eyes after SMILE.

A 3-month comparison study of subjective and objective visual quality of small incision lenticule extraction and transepithelial photorefractive keratectomy in patients with low and moderate myopia

AIM:To compare the subjective and objective visual quality between small incision lenticule extraction(SMILE)and transepithelial photorefractive keratectomy(t PRK)in patients with low and moderate myopia.METHODS:Patients undertaking SMILE or t PRK for the correction of low and moderate myopia were consecutively recruited in this prospective cohort study with a 3-month follow-up period.Objective evaluation[visual acuity test,manifest refraction,wavefront aberrations,the total cut-off value of the total modulation transfer function(MTFcut-off),and Strehl ratio(SR)]and subjective evaluation of visual quality(quality-of-life questionnaire)were conducted before surgery and at days 1,7,30,and 90 after surgery.RESULTS:A total of 47 patients(94 eyes)with SMILE and 22 patients(22 eyes)with t PRK were enrolled.The uncorrected visual acuity(UCVA)was better in SMILE patients on day 7 after surgery(1.13±0.13 vs 0.99±0.17,t=4.85,P<0.001)but was comparable at days 30 and 90.At day 90,the SMILE group had a lower spherical equivalent(SE)than the t PRK group(0.04±0.31 vs 0.19±0.43,t=2.08,P=0.042).Total higher order aberrations(HOAs)were induced in both surgical types,which were more evident in the t PRK group with 3-mm pupil diameter(0.16±0.07 vs0.11±0.05,t=4.27,P<0.001)and 5-mm pupil diameter(0.39±0.17 vs 0.36±0.11,t=2.33,P=0.022).The MTFcut-offand SR showed a trend of improvement in both SMILE and t PRK patients but were statistically better in the SMILE group with both pupil diameters.There was a significant improvement of contrast sensitivity(CS)over baseline levels at the spatial frequency of 18 cycles/degree(c/d)in the SMILE group(F=2.72,P=0.033)and at 3 c/d(F=3.03,P=0.031),12 c/d(F=3.72,P=0.013),and 18 c/d(F=4.62,P=0.004)in the t PRK group.The subjective quality of life questionnaire showed a steady improvement in the SMILE group(F=8.31,P<0.001)but not the t PRK group.CONCLUSION:SMILE and t PRK are both safe and effective ways to correct low and moderate myopia.A generally better and quicker recovery of visual quality favors the application of SMILE in qualified patients.

Comparative study of functional optical zone:small incision lenticule extraction versus femtosecond laser assisted excimer laser keratomileusis

AIM:To investigate the size of functional optical zone(FOZ)after small incision lenticule extraction(SMILE)versus femtosecond laser assisted excimer laser keratomileusis(FS-LASIK)for myopia correction and potential associated factors for FOZ.METHODS:A total of 133 patients who received corneal refractive surgery in our hospital between November 2018 and July 2021 were retrospectively enrolled.There were 63 patients(123 eyes)in SMILE group and 70patients(139 eyes)in FS-LASIK group.The size of FOZ was measured using Pentacam 3-dementional anterior segment analyzer before and 3mo after surgery,so as to analyze postoperative achieved functional optical zone(AFOZ)and its contributing parameters.RESULTS:When planned functional optical zone(PFOZ)was 6.5 mm for both groups,AFOZ was 1.45±0.27 and 1.67±0.25 mm smaller than preoperative FOZ in SMILE group and FS-LASIK group 3mo after surgery.AFOZ in SMILE group was significantly larger than that in FS-LASIK group(P<0.001).Variation of FOZ was negatively correlated with preoperative spherical equivalent(SE)and positively correlated with variation of mean keratometry value(△Km),variation of spherical aberration(△SA),and variation of Q-value(△Q,all P<0.001)in both groups.Multiple variable linear regression equations were△FOZ=1.354-0.1×pre-SE+0.336×△Q+1.462×△SA in SMILE group and△FOZ=1.512+0.137×△Q+0.468×△SA in FS-LASIK group.CONCLUSION:AFOZ is significantly smaller than preoperative FOZ in both SMILE and FS-LASIK groups.With the same PFOZ,larger AFOZ is achieved in SMILE group than in FS-LASIK group.

Treatment of corneal dermoid with lenticules from small incision lenticule extraction surgery:a surgery assisted by fibrin glue

AIM:To observe the clinical efficacy of the combined use of small incision lenticule extraction(SMILE)-derived lenticule patches in corneal dermoid excision,with fixation of the lenticule patches assisted by fibrin glue.METHODS:Seventeen eyes of 17 patients with corneal dermoid were treated with dermoid removal combined with SMILE-derived lenticule transplantation.All lenticule patches were fixed by fibrin glue.Ocular changes were assessed using slit lamp microscopy and anterior-segmental optical coherence tomography.The best-corrected visual acuity(BCVA)and ocular dioptric variations were examined preoperatively and postoperatively.Intraocular pressure(IOP)was also monitored in all visited time.RESULTS:Totally,18 lenticule patches were used on 17 eyes of 17 cornea dermoid patients.The mean follow-up time was 11.47±5.28mo.All lenticule patches we resuccessfullyg lued,kept on its location and maintained transparent during the follow-up time,with a consecutive epithelial cover for 1wk.Nine of the patients could coordinate visual and optometry exam well.Their preoperative BCVA is 0.60±0.35 in decimal,significantly improved to 0.80±0.26 in decimal at 6mo postoperatively(Z=-2.392,P=0.017),but the changes of their corneal astigmatism diopters showed no significance,with 2.22±1.91 D preoperatively,and 2.28±1.31 D at 6mo postoperatively(Z=-0.135,P=0.893).Limbal pannus formation occurred in 4(23.52%)cases and decreased with the application of tacrolimus eyedrops.IOP increased in 2(11.76%)cases,but well decreased by timolol maleate eyedrops.All the adult patients or guardians of minor patients were satisfied with the cosmetic improvement.CONCLUSION:Dermoid excision combined with transplantation of SMILE-derived lenticule patches using fibrin glue is a safe and effective novel tectonic keratoplasty procedure for corneal dermoid.

Comparison of surgically induced astigmatism in various incisions in manual small incision cataract surgery

AIMTo determine the surgically induced astigmatism (SIA) in Straight, Frown and Inverted V shape (Chevron) incisions in manual small incision cataract surgery (SICS).

Outcomes after combined excisional goniotomy and manual small incision cataract surgery

AIM: To report the long-term outcomes of combined excisional goniotomy and manual small incision cataract surgery(MSICS).METHODS: This is a retrospective case series of patients with open angle glaucoma and visually significant cataracts that underwent combined excisional goniotomy and MSICS with one-year follow-up. The medical history, demographic information, and clinical characteristics of each case were recorded. Data regarding changes in vision, intraocular pressure(IOP), the number of glaucoma medications, and the evolution of the disease after surgery were reported. RESULTS: Three patients, with open angle glaucoma and cataracts underwent combined excisional goniotomy and MSICS without adverse events. All patients had improvement in vision compared to baseline measurements. The range of IOP at baseline was from 14 to 18 mm Hg and decrease to a range of 10 to 14 mm Hg after one year of follow-up. Additionally, two patients also decreased their dependence on IOP-lowering medications at the last follow up visit with one patient maintaining baseline level of medication use.CONCLUSION: A combination of excisional goniotomy and MSICS illustrates both the safety and efficacy to treat patients with visually significant cataract and glaucoma. This procedure allows for a more cost-effective surgical approach that matches the needs of resource strained territories around the globe.

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.

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.

Dry eye and corneal sensitivity after small incision lenticule extraction and femtosecond laser-assisted in situ keratomileusis:a Meta-analysis

AIM：To assess the corneal sensitivity and the incidences of dry eye after small incision lenticule extraction（SMILE） and femtosecond laser-assisted in situ keratomileusis（FSLASIK）.METHODS：The Meta-analysis was performed using Rev Man 5.3.We searched on Pub Med from inception to March 2016.Summary weighted mean difference（WMD） and 95% confidence intervals（CIs） were used to analyze the datum.Random-effects or fixed-effects models were chosen up to between-study heterogeneity.The main outcomes were composed of the Ocular Surface Disease Index（OSDI） scores,tear film break-up time（TBUT）,Schirmer Test and corneal sensitivity.RESULTS：Eight eligible studies including 772 eyes（386 in SMILE group and 386 in FS-LASIK group） were identified.The parameters have no significiant difference heterogeneity between SMILE and FS-LASIK group preoperatively.There were significant differences between the two groups in OSDI scores at one and three months postoperatively,in TBUT at one and three months postoperatively,in corneal sensitivity at one week,about one month and three months postoperatively.However,there was no significant difference observed in Schirmer Test at the follow-up periods.CONCLUSION：Compare to FS-LASIK,dry eye and the corneal sensitivity recover better in the SMILE group,in first three months after the surgery.

Phacoemulsification versus small incision cataract surgery in patients with uveitis

AIMTo compare the safety and efficacy of phacoemulsification and small incision cataract surgery (SICS) in patients with uveitic cataract.METHODSIn a prospective, randomized multi-centric study, consecutive patients with uveitic cataract were randomized to receive phacoemulsification or manual SICS by either of two surgeons well versed with both the techniques. A minimum inflammation free period of 3mo (defined as less than 5 cells per high power field in anterior chamber) was a pre-requisite for eligibility for surgery. Superior scleral tunnel incisions were used for both techniques. Improvement in visual acuity post-operatively was the primary outcome measure and the rate of post-operative complications and surgical time were secondary outcome measures, respectively. Means of groups were compared using t-tests. One way analysis of variance (ANOVA) was used when there were more than two groups. Chi-square tests were used for proportions. Kaplan Meyer survival analysis was done and means for survival time was estimated at 95% confidence interval (CI). A P value of &#x0003c;0.05 was considered statistically significant.RESULTSOne hundred and twenty-six of 139 patients (90.6%) completed the 6-month follow-up. Seven patients were lost in follow up and another six excluded due to either follow-up less than six months (n=1) or inability implant an intraocular lens (IOL) because of insufficient capsular support following posterior capsule rupture (n=5). There was significant improvement in vision after both the procedures (paired t-test; P&#x0003c;0.001). On first postoperative day, uncorrected distance visual acuity (UDVA) was 20/63 or better in 31 (47%) patients in Phaco group and 26 (43.3%) patients in SICS group (P=0.384). The mean surgically induced astigmatism (SIA) was 0.86&#x000b1;0.34 dioptres (D) in the phacoemulsification group and 1.16&#x000b1;0.28 D in SICS group. The difference between the groups was significant (t-test, P=0.002). At 6mo, corrected distance visual acuity (CDVA) was 20/60 or better in 60 (90.9%) patients in Phaco group and 53 (88.3%) in the manual SICS group (P=0.478). The mean surgical time was significantly shorter in the manual SICS group (10.8&#x000b1;2.9 versus 13.2&#x000b1;2.6min) (P&#x0003c;0.001). Oral prednisolone, 1 mg/kg body weight was given 7d prior to surgery, continued post-operatively and tapered according to the inflammatory response over 4-6wk in patients with previously documented macular edema, recurrent uveitis, chronic anterior uveitis and intermediate uveitis. Rate of complications like macular edema (Chi-square, P=0.459), persistent uveitis (Chi-square, P=0.289) and posterior capsule opacification (Chi-square, P=0.474) were comparable between both the groups.CONCLUSIONManual SICS and phacoemulsification do not differ significantly in complication rates and final CDVA outcomes. However, manual SICS is significantly faster. It may be the preferred technique in settings where surgical volume is high and access to phacoemulsification is limited, such as in eye camps. It may also be the appropriate technique for uveitic cataract under such circumstances.

Early changes to dry eye and ocular surface after smallincision lenticule extraction for myopia

AIM： To investigate the early changes in dry eye symptoms, tear function and ocular surface following small-incision lenticule extraction（SMILE） for myopia.·METHODS： Ninety-seven consecutive patients（193 eyes）who underwent SMILE for myopia were observed in this longitudinal and retrospective study. Parameters evaluated included： subjective dry eye symptoms（dryness, foreign body sensation and photophobia）, tear film breakup time（TBUT）, Schirmer Ⅰ test without anesthesia（S Ⅰ T）, tear meniscus height（TMH） and corneal fluorescein staining. Each parameter was evaluated before, and subsequently at 1d, 1wk, 1 and3 mo after surgery.·RESULTS： Compared with preoperative data, dryness was noted to be significantly increased at 1wk and 1mo postoperatively（P 〈0.01）. Symptoms of photophobia and foreign body sensation demonstrated significant differences at 1d and 1wk as compared with preoperative scores respectively（P 〈0.01）. These values were decreased at 1 and 3mo post-surgery（P 〉0.05）.Conversely the corneal staining scores were higher than the preoperative data at 1d, 1wk and 1mo（P 〈0.01）, but were close to the preoperative level at 3mo postoperatively. There was a significant decrease in TMH at 1wk and 1mo（P 〈0.01）, but the value was close to the preoperative level at 3mo postoperatively（P =0.16）. The examination outcomes of S Ⅰ T were significantly increased at 1d then reduced at 1wk after surgery（P 〈0.01）. Each value subsequently returned to the baseline value at 1 and 3mo（P 〉0.05）. TBUT was significantly decreased at all postoperative time points（P 〈0.01）.· CONCLUSION： SMILE resulted in mild dry eye symptoms, tear film instability and ocular surface damages; however, these complications can recover in a short period of time.

Simple method of measuring ocular rotation in supine position during small incision lenticule extraction

AIM:To introduce a novel measurement method of static cyclotorsion in small incision lenticule extraction(SMILE)and to investigate the effect of preoperative parameters on cyclotorsion and the effect of cyclotorsion on postoperative outcomes.METHODS:The medical records of 242 patients and 484 eyes who under went SMILE surger y were retrospectively reviewed.Preoperative intraocular pressure,refractive error,and corneal thickness were investigated.Refractive values and visual acuity were measured at 1d,1,3,and 6mo.Ocular cyclotorsion in the supine position was measured by calculating the location and angle of the incision site of the cornea in the anterior slit photograph taken after surgery.RESULTS:Of the total 484 eyes in 242 patients,preopera tive means phericale quivalent(SE)was-4.10±1.64 D,and the mean astigmatism was-0.82±0.74 D.Uncorrected distance visual acuity(UCVA)and SE improved significantly after the surgery.Moreover,219(45.2%)eyes had excyclotorsion,235(48.6%)eyes had incyclotorsion,and 30(6.2%)eyes had no torsion.The right eyes tended to be excyclotorted,and the left eyes tended to be incyclotorted(P<0.01).The mean cyclotorsion was 1.18°±3.69°,and the mean absolute value of cyclotorsion was 3.14°±2.26°.The range of cyclotorsion was 0.5°–11.4°.It was found that the smaller the preoperative sphere,the higher the amount of cyclotorsion(r=0.11,P=0.016).There was no significant association between the amount of cyclotorsion and preoperative astigmatism.There was no correlation between sex,preoperative corneal thickness,preoperative intraocular pressure,amount of cyclotorsion,and direction of cyclotorsion.The ratio of right eye excyclotorsion and left eye incyclotorsion on 1d was higher than that at 1,3,and 6mo(all P<0.01).There was no difference between the 1,3,and 6mo results in the right and left eyes(P=0.15,P=0.16,respectively).CONCLUSION:The newly devised ocular cyclotorsion measurement method can be used to evaluate ocular cyclotorsion after SMILE.Preoperative SE is associated with the amount of cyclotorsion,however,cyclotorsion doesn't have a significant effect on the results of SMILE surgery.

Cataract surgery in aged patients:phacoemul-sification or small-incision extracapsular cataract surgery

AIM: To evaluate the effects and safety of phacoemulsification (Phaco) or small-incision extracapsular cataract surgery (SICS) and intraocular lens (IOL) implantation for aged patients. METHODS: Totally 137 aged patients (149 eyes) underwent cataract operation in the case of stable systemic condition, the blood pressure less than 160/95mmHg, blood glucose less than 8mmol/L, and under the help of electrocardiogram surveillance by anesthesiologists during the operation. 106 aged patients (114 eyes) underwent Phaco while 31 aged patients (35 eyes) underwent SICS. The postoperative visual acuity, corneal endothelial cell loss, surgery time and major complications were observed and analyzed retrospectively. RESULTS: The best-corrected visual acuity (BCVA) of >= 0.6 was achieved in 135 eyes (92.6%) at 1 month postoperatively (chi(2)=259.730, P<0.001). For aged patients, both Phaco and SICS could significantly improve visual acuity with no significant difference (chi(2)=4.535, P > 0.05). Postoperative corneal endothelial cell loss was 18.6%, in PHACO group, the rate was 18.5%; in SICS group, the rate was 19.0%, the difference of which was no significant (chi(2)=0.102, P>0.05). The surgery time was different in two groups. No severe complications occurred. CONCLUSION: Both Phaco and SICS combined with IOL implantation for aged patients are effective and safe. Before surgery, detailed physical examination should be performed. When the systemic condition is stable, cataract surgery for aged patients is safe.

Small-incision lenticule extraction versus femtosecond lenticule extraction for myopic:a systematic review and Meta-analysis

AIM： To examine differences in efficacy, accuracy, safety, aberrations and corneal biomechanical between Small incision lenticule extraction （SMILE） and femtosecond lenticule extraction （FLEx） for myopia. METHODS： Comprehensive studies were conducted on the PubMed, MEDLINE, EMBASE, and Cochrane Controlled Trials Register before 31 July, 2015. Meta-analyses were performed on the primary outcomes [loss of ≥2 lines of corrected distance visual acuity （CDVA）, uncorrected distance visual acuity （UDVA） ≥20/20, spherical equivalent （SE） within ±0.50 diopters （D）, final refractive SE], secondary outcomes were high-order aberrations （HOAs） and corneal biomechanical [central corneal thickness （CCT）, corneal hysteresis （CH） and corneal resistance factor （CRF）]. RESULTS： Seven trials describing a total of 320 eyes with myopia were included in this Meta-analysis. No significant differences were found in the efficacy [UDVA weighted mean difference （WMD） -0.01; 95%CI： -0.04 to 0.01; P=0.37, UDVA ≥20/20, OR 1.49; 95%CI： 0.78 to 2.86; P=0.23], accuracy （SE WMD -0.03; 95%CI： -0.12 to 0.07; P=0.58 , SE within ±0.5 D OR 1.25; 95%CI： 0.34 to 4.65; P=0.74）, HOAs （WMD -0.04; 95%CI： -0.09 to 0.01; P=0.14） and CCT WMD 1.83; 95%CI： -7.07 to 10.72; P=0.69, CH WMD -0.01; 95%CI： -0.42 to 0.40; P=0.97, CRF WMD 0.17; 95%CI： -0.33 to 0.67; P=0.50） in the last fellow-up. But for safety, FLEx may achieve fewer CDVA lost two or more two lines （OR 11.11; 95%CI： 1.27 to 96.86; P=0.03） than SMILE, however CDVA （WMD 0.00; 95%CI： -0.03 to 0.02; P=0.77） is similar. CONCLUSION： SMILE and FLEx are comparable in terms of both efficacy, accuracy, aberrations and corneal biomechanical measures in the follow-up,but FLEx seems to be better in safety measures. The results should be interpreted cautiously since relevant evidence is still limited, although it is accumulating. Further large-scale, well-designed randomized controlled trials are urgently needed.

Cap morphology after small-incision lenticule extraction and its effects on intraocular scattering

AIM： To investigate cap morphology after small-incision lenticule extraction （SMILE） and its effects on intraocular scattering. METHODS： Sixty-five eyes of 33 patients undergoing SMILE were enrolled. In addition to regular evaluation, Fourier-domain optical coherence tomography was used to investigate cap thickness at ld, lwk, 1 and 3mo postoperatively. The optical quality including modulation transfer function cutoff frequency, Strehl ratio, Optical Quality Analysis System （OQAS） values, and objective scattering index （OSI）, were evaluated using OQASTM. RESULTS： Cap thickness decreased from ld to lwk （P〈0.001）, but remained higher than intended thickness of 120 μm after 3mo （P〈0.001）. Cap thickness in central area was thinner than that of in the paracentral and peripheral areas （P〈0.0001）. Total number of microdistortions decreased from ld to 3mo （P〈0.0001）. Pearson analysis revealed a weak correlation between OSI and standard deviation of cap thickness at ld and lmo, as well as between range of cap thickness and OSI at 1mo. No correlation was found between microdistortion and OSI, but a negative correlation existed between microdistortion and range at ld and lmoafter surgery. CONCLUSION： The corneal cap tends to be more accurate and regular with time lapse. Better cap morphology tends to contribute less intraocular scattering in the eyes undergoing SMILE.