Accuracy of segmented measurement of axial length in ultra-high myopia filled with silicone oil using immersion B-scan ultrasonography

AIM:To evaluate the accuracy of segmented measurement of axial length(AL)in high myopia filled with silicone oil by immersion B-scan ultrasonography(immersion B-scan).METHODS:From June 2016 to June 2020,a total of 67 ultra-high myopia inpatients(67 eyes)who underwent silicone oil removal combined with cataract extraction and intraocular lens(IOL)implantation were retrospectively enrolled.The preoperative axial length(AL)of 31 patients with severe cataract were segmented measured using immersion B-scan(B-scan group)and another 36 patients with mild or moderate cataract were measured using IOLMaster 500(IOLMaster group).The post-operative ALs in two groups were both measured using IOLMaster 500.The IOL power was calculated with Haigis formula.The differences in ALs between pre-and post-surgery,as well as the postoperative refractive spherical equivalent,absolute refractive error,the prediction deviation of postoperative refraction and best corrected visual acuity(BCVA)were compared.RESULTS:The pre-and post-operative ALs were 30.46±1.63 mm(range 28.09-33.51 mm)and 30.42±1.70 mm(range 28.03-33.90 mm)in B-scan group(t=0.644,P=0.542)and 30.51±1.21 mm(range 28.03-33.90 mm)and 30.43±1.27 mm(range 28.54-33.50 mm)in IOLMaster group(t=1.843,P=0.074),respectively.Three months after surgery,BCVA were 0.45±0.13(range 0.3-0.9)and 0.44±0.20(range 0.2-1.0)in B-scan and IOLMaster group respectively(t=0.086,P=0.932).There was no significant difference of the postoperative spherical equivalent(-3.11±0.65 D vs-3.21±0.51 D,t=0.671,P=0.505)and the absolute refractive error(0.589±0.340 vs 0.470±0.245 D,t=1.615,P=0.112)between two groups.In B-scan group,absolute refractive error within±0.50 D was found in 18 eyes(58.1%),within±1.00 D in 26 eyes(83.9%),and within±1.50 D in 31 eyes(100%).In IOLMaster group,absolute refractive error within±0.50 D was found in 23 eyes(63.9%),within±1.00 D in 34 eyes(94.4%),and within±1.50 D in 36 eyes(Z=0.757,P=0.449).CONCLUSION:The segmented measurement of ALs by immersion B-scan shows comparable measurement accuracy with that of IOLMaster 500 in ultra-high myopia patients with severe cataract secondary to silicone oil filling and can obtain an ideal postoperative refractive state.

The optimal atropine concentration for myopia control in Chinese children: a systematic review and network Metaanalysis

AIM:To figure out whether various atropine dosages may slow the progression of myopia in Chinese kids and teenagers and to determine the optimal atropine concentration for effectively slowing the progression of myopia.METHODS:A systematic search was conducted across the Cochrane Library,PubMed,Web of Science,EMBASE,CNKI,CBM,VIP,and Wanfang database,encompassing literature on slowing progression of myopia with varying atropine concentrations from database inception to January 17,2024.Data extraction and quality assessment were performed,and a network Meta-analysis was executed using Stata version 14.0 Software.Results were visually represented through graphs.RESULTS:Fourteen papers comprising 2475 cases were included;five different concentrations of atropine solution were used.The network Meta-analysis,along with the surface under the cumulative ranking curve(SUCRA),showed that 1%atropine(100%)>0.05%atropine(74.9%)>0.025%atropine(51.6%)>0.02%atropine(47.9%)>0.01%atropine(25.6%)>control in refraction change and 1%atropine(98.7%)>0.05%atropine(70.4%)>0.02%atropine(61.4%)>0.025%atropine(42%)>0.01%atropine(27.4%)>control in axial length(AL)change.CONCLUSION:In Chinese children and teenagers,the five various concentrations of atropine can reduce the progression of myopia.Although the network Meta-analysis showed that 1%atropine is the best one for controlling refraction and AL change,there is a high incidence of adverse effects with the use of 1%atropine.Therefore,we suggest that 0.05%atropine is optimal for Chinese children to slow myopia progression.

One-year results for myopia control of orthokeratology with different back optic zone diameters: a randomized trial using a novel multispectral-based topographer

AIM:To present the 1-year results of a prospective cohort study investigating the efficacy,potential mechanism,and safety of orthokeratology(ortho-k)with different back optic zone diameters(BOZD)for myopia control in children.METHODS:This randomized clinical study was performed between Dec.2020 and Dec.2021.Participants were randomly assigned to three groups wearing ortho-k:5 mm BOZD(5-MM group),5.5 mm BOZD(5.5-MM group),and 6 mm BOZD(6-MM group).The 1-year data were recorded,including axial length,relative peripheral refraction(RPR,measured by multispectral refractive topography,MRT),and visual quality.The contrast sensitivity(CS)was evaluated by CSV-1000 instrument with spatial frequencies of 3,6,12,and 18 cycles/degree(c/d);the corneal higher-order aberrations(HOAs)were measured by iTrace aberration analyzer.The one-way ANOVA was performed to assess the differences between the three groups.The correlation between the change in AL and RPR was calculated by Pearson’s correlation coefficient.RESULTS:The 1-year results of 20,21,and 21 subjects in the 5-MM,5.5-MM,and 6-MM groups,respectively,were presented.There were no statistical differences in baseline age,sex,or ocular parameters between the three groups(all P>0.05).At the 1-year visit,the 5-MM group had lower axial elongation than the 6-MM group(0.07±0.09 vs 0.18±0.11 mm,P=0.001).The 5-MM group had more myopic total RPR(TRPR,P=0.014),with RPR in the 15°–30°(RPR 15–30,P=0.015),30°–45°(RPR 30–45,P=0.011),temporal(RPR-T,P=0.008),and nasal area(RPR-N,P<0.001)than the 6-MM group.RPR 15–30 in the 5.5-MM group was more myopic than that in the 6-MM group(P=0.002),and RPR-N in the 5-MM group was more myopic than that in the 5.5-MM group(P<0.001).There were positive correlations between the axial elongation and the change in TRPR(r=0.756,P<0.001),RPR 15–30(r=0.364,P=0.004),RPR 30–45(r=0.306,P=0.016),and RPR-N(r=0.253,P=0.047).The CS decreased at 3 c/d(P<0.001),and the corneal HOAs increased in the 5-MM group(P=0.030).CONCLUSION:Ortho-k with 5 mm BOZD can control myopia progression more effectively.The mechanism may be associated with greater myopic shifts in RPR.

Retardation of myopia by atropine regimes

Myopia is a huge health problem due to its high frequency,vision losses and public health cost.According to the World Health Organization,at least 2.2 billion people have vision impairment.Although myopia can be controlled at its early and middle stages,unfortunately,no cure can be achieved so far.Among the methods to control myopia,atropine,a muscarinic receptor antagonist,is the oldest but still the most effective for retardation of myopia progression.Despite such a fact,standard protocols have not been established for clinicians to use atropine for treatment of myopia.In this article,a concise and up to date summary of myopia epidemiology and pathogenesis and summarized therapeutic effects and side effects,possible mechanisms and application methods of atropine were provided in hope for clinical doctors to effectively control this problematic disease.At present,the protocol is recommend:use higher dose(1%)of atropine intermittently to effectively slowdown myopia progression in schoolchildren for 2y,and to significantly reduce side effects of atropine by decrease of atropine frequency for 1y and inhibit myopic rebound by withdrawal of topical atropine gradually for 1y.Application of a lower dose(0.05%)atropine regime should also be considered due to its effectiveness and application at regular basis.

A review of mechanism of action of outdoor exposure in preventing myopia incidence and progression

Various studies have suggested several environmental,pharmacological,medical,and optical interventions and some are in use but their efficacy in myopia control may be transient,and the cellular,molecular,and biochemical mechanisms involved unclear.Daylight exposure is currently regarded as an effective and enduring strategy in the control of myopia development and progression.However,the mechanism behind the effect of outdoor exposure and its association with genetic predisposition and other relatively more significant environmental factors on myopia is still a conundrum.This review focuses on survey-based and intervention-based studies carried out to propose a mechanism that accounts for myopia development and important for its control.

Parental awareness on myopia prevention and control among 350 children

AIM:To understand the current situation of parental perspectives,knowledge,and practices concerning myopia prevention and control for both pre-and school-aged children.METHODS:This study was a cross-sectional survey that involved children aged 0 to 15y and their parents.Participants were required to respond to an online questionnaire by scanning a quick response(QR)code.The questionnaire consisted of 25 tick-box questions and was open to response from December 22,2022,to January 5,2023.The dioptric traits of the children,the visual status and educational background of the parents,the parental perspectives towards myopia and its risks,and the parents’knowledge and practices related to myopia prevention and control were recorded and measured.The Chi-square test and binomial logistic regression were used for statistics.RESULTS:Totally 350 parents responded to the questionnaire.The prevalence and severity of myopia among the surveyed children exhibited a positive correlation with advancing age(P<0.001 and P=0.004,respectively).Nearly half of parents with myopic children considered myopia did not pose any health threat and could be effectively corrected(P<0.001).Parents who held master’s or doctoral degree demonstrated a better understanding of children’s vision standards for each age group(P=0.001),and 31.63% of them could undergo initial vision screening for their children during the age of 0 to 3y while parents with bachelor’s degree(34.04%)and below(32.43%)mainly initiated the vision examination for their children at the age of 4 to 6y(P=0.05).Parents with master’s or doctoral degree also exhibited more rational practices concerning outdoor time(P=0.048)and sleep time(P=0.044).No other significant discrepancy among the different educational groups in additional conceptions of myopia,such as hyperopia reserve,axis length,and corneal curvature alterations.Most parents preferred to employ conventional interventions,such as enhancing indoor lighting condition(80.00%)and ensuring appropriate reading posture and distance(71.71%).CONCLUSION:The current status of parental knowledge and practices about myopia prevention and control remains outdated and deficient.The administrative department should implement efficacious and adaptable measures to enhance parental awareness and foster their commitment towards myopia prevention and control.

Effects of different orthokeratology lens designs on slowing axial length elongation in children with myopia

AIM:To elucidate whether differences exist in the impact on retarding the elongation of axial length(AL)among children with myopia when utilizing orthokeratology(ortho-k)lenses employing the corneal refractive therapy(CRT)design versus those employing the vision shaping treatment(VST)design.METHODS:This retrospective clinical trial aimed to collect and analyze AL data from individuals who wore ortho-k lenses for three years.A total of 654 subjects were enrolled and prescribed one of the three specific brands of ortho-k lenses:CRT,Euclid,and Mouldway.The study’s primary focus was to compare the rates of AL elongation and myopic progression across these three brands of ortho-k lenses.RESULTS:In the 3-year follow-up,the AL elongation exhibited variations of 0.73±0.36 mm in the CRT lens group,0.59±0.37 mm in the Euclid lens group,and 0.63±0.38 mm in the Mouldway lens group.A noteworthy disparity emerged between the CRT and Mouldway groups(P<0.01),as well as between the CRT and Euclid groups(P<0.001).Additionally,it was observed that 32.1%of participants who wore CRT lenses experienced a decelerated progression of myopia,in contrast to 47.2%in the Euclid group and 44.4%in the Mouldway group.Statistical analyses revealed a statistically significant distinction between the CRT and Euclid groups(P<0.01),and similarly,the CRT group demonstrated a statistically significant difference when compared to the Mouldway group(P<0.05).CONCLUSION:Ortho-k lenses represent a pragmatic strategy for mitigating the advancement of myopia.In contradistinction to ortho-k lenses utilizing the CRT design,those employing the VST design exhibited a more favorable impact regarding retarding AL elongation.

Bibliometric analysis of hotspots and trends of global myopia research

AIM:To gain insights into the global research hotspots and trends of myopia.METHODS:Articles were downloaded from January 1,2013 to December 31,2022 from the Science Core Database website and were mainly statistically analyzed by bibliometrics software.RESULTS:A total of 444 institutions in 87 countries published 4124 articles.Between 2013 and 2022,China had the highest number of publications(n=1865)and the highest H-index(61).Sun Yat-sen University had the highest number of publications(n=229)and the highest H-index(33).Ophthalmology is the main category in related journals.Citations from 2020 to 2022 highlight keywords of options and reference,child health(pediatrics),myopic traction mechanism,public health,and machine learning,which represent research frontiers.CONCLUSION:Myopia has become a hot research field.China and Chinese institutions have the strongest academic influence in the field from 2013 to 2022.The main driver of myopic research is still medical or ophthalmologists.This study highlights the importance of public health in addressing the global rise in myopia,especially its impact on children’s health.At present,a unified theoretical system is still needed.Accurate surgical and therapeutic solutions must be proposed for people with different characteristics to manage and intervene refractive errors.In addition,the benefits of artificial intelligence(AI)models are also reflected in disease monitoring and prediction.

Age-specific distribution of oculometric parameters and myopia in children aged 8-12y

AIM:To describe the distribution of ocular biometrics and to evaluate its associations with refractive error and to assess the contribution from ocular parameters to refractive error among Chinese myopic children.METHODS:This cross-sectional study evaluated subjects aged 8-12y.Keratometry,ocular biometry,and cycloplegic autorefraction were performed on each subject.Spherical equivalent refraction(SER)and ocular biometrics were assessed as a function of age and gender.The Pearson correlation analysis between SER and ocular biometrics was carried out.Multiple linear regression was performed to analyze the association between SER and ocular parameters.RESULTS:A total of 689 out of 735 participants(321 boys,48.1%)were analyzed,with a mean SER of-2.98±1.47 diopter(D).Axial length(AL),anterior chamber depth(ACD),corneal radius of curvature(CR),horizontal visible iris diameter(HVID),central corneal thickness(CCT)and lens power(LP)showed normal distribution.The AL,AL/CR ratio,ACD and CR increased from 8 to 12y of age,while SER and LP decreased,HVID and CCT remained stable.There was no difference in gender.SER decreased by 0.929 D for every 1 mm increase in AL and decreased by 1.144 D for every 0.1 increase in AL/CR ratio.The Pearson correlation coefficient between SER and AL was-0.538(P<0.01)and-0.747(P<0.01)between SER and AL/CR ratio.For the SER variance,AL explained 29.0%,AL/CR ratio explained 55.7%,while AL,CR,ACD and LP explained 99.3%after adjusting for age and gender.CONCLUSION:The AL,CR,ACD and LP are the most important determinants of myopic refractive error during myopia progression.

Ocular surface in patients with different degrees of myopia

AIM:To investigate the clinical features of the ocular surface in patients with different degrees of myopia.METHODS:A cross-sectional study was conducted involving 122 participants with myopia in Beijing Tongren Hospital from February to June,2023.After completing the Ocular Surface Disease Index(OSDI)score scale,measurements were taken for refraction,biometric parameters and ocular surface parameters.The prevalence,severity and related parameters of the dry eye among different groups based on axial length(AL)were compared.Correlation analysis was performed between ocular surface parameters and refraction/biometric measurement parameters.RESULTS:Statistically significant differences were observed in refractive error,corneal thickness,anterior chamber depth,and subfoveal choroidal thickness among the groups(all P<0.05).With the increase in AL,the incidence and severity of dry eye increased significantly(P<0.05).Moreover,the tear film break-up time(BUT)shortened(P<0.05),and the corneal fluorescein staining(CFS)points increased significantly(P<0.05).OSDI scores were positively correlated with AL and spherical equivalent(SE;both P<0.05);BUT was negatively correlated with AL,SE,and corneal astigmatism(AST;all P<0.05);Schirmer I test(SIT)results were negatively correlated with AL and SE(both P<0.05).CONCLUSION:AL elongation is a risk factor for dry eye onset in myopic participants.The longer the AL,the more severe the dry eye is,with the increased CFS spots and tear film instability.Additionally,SE and AST exhibit negative correlations with dry eye symptom scores and ocular surface parameters.

Mechanical Behavior Based on Aggregates Microstructure of Ultra-high Performance Concrete

We developed ultra-high performance concrete(UHPC)incorporating mullite sand and brown corundum sand(BCS),and the quartz sand UHPC was utilized to prepare for comparison.The properties of compressive strength,elastic modulus,ultrasonic pulse velocity,flexural strength,and toughness were investigated.Scanning electron microscopy and nanoindentation were also conducted to reveal the underlying mechanisms affecting macroscopic performance.Due to the superior interface bonding properties between mullite sand and matrix,the compressive strength and flexural toughness of UHPC have been significantly improved.Mullite sand and BCS aggregates have higher stiffness than quartz sand,contributing to the excellent elastic modulus exhibited by UHPC.The stiffness and volume of aggregates have a more significant impact on the elastic modulus of UHPC than interface performance,and the latter contributes more to the strength of UHPC.This study will provide a reference for developing UHPC with superior elastic modulus for structural engineering.

Dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates

Interactive holography offers unmatched levels of immersion and user engagement in the field of future display.Despite of the substantial progress has been made in dynamic meta-holography,the realization of real-time,highly smooth interactive holography remains a significant challenge due to the computational and display frame rate limitations.In this study,we introduced a dynamic interactive bitwise meta-holography with ultra-high computational and display frame rates.To our knowledge,this is the first reported practical dynamic interactive metasurface holographic system.We spa-tially divided the metasurface device into multiple distinct channels,each projecting a reconstructed sub-pattern.The switching states of these channels were mapped to bitwise operations on a set of bit values,which avoids complex holo-gram computations,enabling an ultra-high computational frame rate.Our approach achieves a computational frame rate of 800 kHz and a display frame rate of 23 kHz on a low-power Raspberry Pi computational platform.According to this methodology,we demonstrated an interactive dynamic holographic Tetris game system that allows interactive gameplay,color display,and on-the-fly hologram creation.Our technology presents an inspiration for advanced dynamic meta-holography,which is promising for a broad range of applications including advanced human-computer interaction,real-time 3D visualization,and next-generation virtual and augmented reality systems.

Covering corneal stromal lenticule for macular hole in pathological myopia

AIM:To evaluate the clinical effect of a new surgery technique(covering corneal stromal lenticule,CSL)for macular hole(MH)in pathological myopia.METHODS:This was a prospective non-randomized series case study.Fourteen eyes of 14 patients whose axial length were more than 29 mm and suffered from MH and macular hole retinal detachment(MHRD)were included in this study.All cases were treated with 25-gauge pars plana vitrectomy(PPV)with internal limiting membrane(ILM)peeling,covering CSL and C_(3)F_(8) gas tamponade.These cases were followed for 6mo,and the best-corrected visual acuity(BCVA),healing status of MH,the reattached rate of retinal detachment(RD),and reoperation rate were analyzed.RESULTS:All cases were successfully performed the surgery and the postoperative follow-up was completed.After surgery,MHs were healed in all 14 eyes(100%,14/14)after assessed by optical coherence tomography.The reattachment of retina was achieved in all 6 eyes(100%,6/6)with MHRD.BCVA was improved in 12 eyes(85.71%,12/14),and had no significant change in 2 eyes(14.29%,2/14).The overall mean BCVA was improved from 1.80±0.77 to 0.82±0.46 logMAR(F=10.46,P<0.01).No serious complications occurred in all cases.CONCLUSION:The new surgery technique(covering CSL)has high reattached rate of RD and high healing rate of MH in pathological myopia in the preliminary study.And it can effectively improve the visual function of patients.This new technique offers meaningful new ideas for treating refractory MH in pathological myopia.

Effect of artificial natural light on the development of myopia among primary school-age children in China:a three-year longitudinal study

AIM:To assess the efficacy of artificial natural light in preventing incident myopia in primary school-age children.METHODS:This is a prospective,randomized control,intervention study.A total of 1840 students from 39 classes in 4 primary schools in Foshan participated in this study.The whole randomization method was adopted to include classes as a group according to 1:1 randomized control.Classrooms in the control group were illuminated by usual light,and classrooms in the intervention group were illuminated by artificial natural light.All students received uncorrected visual acuity and best-corrected visual acuity measurement,non-cycloplegic autorefraction,ocular biometric examination,slit lamp and strabismus examination.Three-year follow-up,the students underwent same procedures.Myopia was defined as spherical equivalent refraction≤-0.50 D and uncorrected visual acuity<20/20.RESULTS:There were 894 students in the control group and 946 students in the intervention group with a mean±SD age of 7.50±0.53y.The three-year cumulative incidence rate of myopia was 26.4%(207 incident cases among 784 eligible participants at baseline)in the control group and 21.2%(164 incident cases among 774 eligible participants at baseline)in the intervention group[difference of 5.2%(95%CI,3.7%to 10.1%);P=0.035].There was also a significant difference in the three-year change in spherical equivalent refraction for the control group(-0.81 D)compared with the intervention group[-0.63 D;difference of 0.18 D(95%CI,0.08 to 0.28 D);P<0.001].Elongation of axial length was significantly different between in the control group(0.77 mm)and the intervention group[0.72 mm;difference of 0.05 mm(95%CI,0.01 to 0.09 mm);P=0.003].CONCLUSION:Artificial natural light in the classroom of primary schools can result in reducing incidence rate of myopia during a period of three years.

Causal association of obesity-related anthropometric traits with myopia and the mediating role of educational attainment:a Mendelian randomization study

AIM:To study the causal relationship between obesityrelated anthropometric traits and myopia and the mediating role of educational attainment(EA).METHODS:Univariable Mendelian randomization(UVMR)was performed to evaluate the causal association between body mass index(BMI),height,waist-hip ratio(WHR,adjusted for BMI),and mean spherical equivalent(MSE).BMI was divided into fat and fat-free mass and included in multivariable Mendelian randomization(MVMR)to explore the roles of different BMI components in the causal relationship between BMI and MSE.A mediation analysis based on two-step Mendelian randomization(MR)was carried out.Specifically,UVMR was conducted to estimate the causal effect of BMI on EA.The direct effect of EA on MSE was estimated from MVMR.The mediation effect of EA in the BMI-EA-MSE model was calculated by the product of coefficients method.Expression quantitative trait loci(eQTL)-MR,reverse MR,and Linkage Disequilibrium Score Regression(LDSC)were performed to assess the robustness.RESULTS:Genetically predicted higher BMI had a positive total effect on MSE(βIVW=0.26 D,95%CI=0.14 to 0.37 D,P<0.001),whereas there was no significant association between height,WHR,and MSE.Fat mass was found to play a significant role in the effect of body mass on MSE(βIVW=0.50 D,95%CI=0.21 to 0.78 D,P=0.001),but there was no significant association between fat-free mass and MSE.The causal effect of BMI on EA was-0.14(95%CI=-0.16 to-0.11,P<0.001),and the direct effect of EA on MSE was-0.63 D(95%CI=-0.81 to-0.44 D,P<0.001).The mediating effect of EA in the BMI-EA-MSE model was 0.09 D(95%CI=0.06 to 0.12 D),with a mediation proportion of 33%(95%CI=22.1%to 44.6%).No reverse causal associations were detected except for BMI on EA.The results of eQTL-MR and LDSC were consistent with each MR analysis.CONCLUSION:Genetically predicted higher BMI decreases the degree of myopia with a 33%mediation proportion by EA,and fat mass provides a dominant protective role in body mass-myopia.As a supplement to previous observational studies,it provides strong evidence for the relationship between anthropometric traits and refractive errors and offers a theoretical basis for future measures to prevent and control myopia.

The Influence of Chemical Admixtures on the Fluidity,Viscosity and Rheological Properties of Ultra-High Performance Concrete

To achieve higher strength and better durability,ultra-high performance concrete(UHPC)typically employs a relatively small water-binder ratio.However,this generally leads to an undesired increase in the paste viscosity.In this study,the effects of liquid and powder polycarboxylate superplasticizers(PCE)on UHPC are compared and critically discussed.Moreover,the following influential factors are considered:air-entraining agents(AE),slump retaining agents(SA),and defoaming agents(DF)and the resulting flow characteristics,mechanical properties,and hydration properties are evaluated assuming UHPC containing 8‰powder PCE(PCE-based UHPC).It is found that the spread diameter of powder PCE is 5%higher than that of liquid PCE.Among the chemical admixtures studied,AEs have the best effect on improving UHPC workability,while DFs have the worst effect.When the addition of AE and SA is 1.25‰and 14.7%of PCE,paste viscosity reduces by 35%and 19%,respectively compared to the paste with only 8‰PCE.A low AE dosage(1.25‰)decreases compressive strength by 4.1%,while SA(8.1%)increases UHPC compressive strength by 9.1%.Both AE and SA significantly delay the UHPC hydration process,reducing the hydration heat release peaks by 76%and 27%,respectively.

Effectivity and safety of trifocal intraocular lenses and capsular tension rings implantation for cataract patients with axial high myopia

●AIM:To assess effectivity and safety of trifocal intraocular lenses(IOLs)and capsular tension rings in treating cataract patients with axial high myopia.●METHODS:A prospective nonrandomized controlled clinical trial was conducted.Totally 98 eyes(74 patients)who underwent femtosecond laser-assisted cataract surgery(FLACS)with trifocal IOLs were enrolled in the study and followed up for 2y after surgery:46 eyes(33 patients)with capsular tension ring implantation in the long axial lengths(AL)group(26<AL<29 mm)and 52 eyes(41 patients)in the normal AL group(22<AL<24.5 mm).Postoperative outcomes about effectivity and safety,including the subjective and objective visual quality,and postoperative complications were assessed.●RESULTS:Uncorrected distance visual acuity at 5 m and uncorrected intermediate visual acuity at 60 and 80 cm in the long AL group were significantly worse than those in the normal AL group at 3mo postoperatively(P<0.05).The differences in reading speed,spectacle independence and potential visual complaints between the two groups were not statistically significant(P>0.05).The dysfunctional lens index and total modulation transfer function(MTF)average height were similar between the two groups.The postoperative internal coma aberrations in the axial high myopia eyes were significantly higher than that in the normal AL group(P<0.05).The total satisfaction score in the long AL group(91.32±2.76)was slightly higher than that in the normal AL group(90.36±3.47),but there was no difference(P=0.136).A statistically negative correlation was found between corrected distance visual acuity(CDVA)and dysfunctional lens index(r=-0.382,P=0.009),and between CDVA and the total MTF average height(r=-0.374,P=0.01).But there was no significant correlation between CDVA and total satisfaction score(r=0.059,P=0.696).Postoperative complications mainly presented as posterior capsular opacity(PCO),retinal detachment and cystoid macular edema.There was no difference in the incidence of fundus disease(6.5%vs 3.8%,P=0.663)or PCO(17.4%vs 7.7%,P=0.217)between the two groups at two years.●CONCLUSION:The utilization of trifocal IOL and capsular tension ring implantation is beneficial for cataract patients with axial high myopia undergoing FLACS.This approach not only ensures excellent subjective feelings and objective visual quality,but also does not increase the incidence of postoperative complications.

Early changes in corneal densitometry after FS-LASIK combined with accelerated corneal cross-linking for correction of high myopia

AIM:To observe the effects of femtosecond laserassisted excimer laser in situ keratomileusis combined with accelerated corneal cross-linking(FS-LASIK Xtra)on corneal densitometry after correcting for high myopia.METHODS:In this prospectively study,130 patients underwent FS-LASIK or FS-LASIK Xtra for high myopia.Their right eyes were selected for inclusion in the study,of which 65 cases of 65 eyes in the FS-LASIK group,65 patients with 65 eyes in the FS-LASIK Xtra group.Patients were evaluated for corneal densitometry at 1,3,and 6mo postoperatively using Pentacam Scheimpflug imaging.RESULTS:Preoperative differences in corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups in different ranges were not statistically significant(P>0.05).Layer-by-layer analysis revealed statistically significant differences in the anterior(120μm),central,and total layer corneal densitometry between the FS-LASIK and FS-LASIK Xtra groups at 1 and 3mo postoperatively(all P<0.05),the FS-LASIK Xtra group is higher than that of the FS-LASIK group.Analysis of different diameter ranges showed statistically significant differences between the FS-LASIK group and the FS-LASIK Xtra group at 1mo postoperatively in the ranges of 0–2,2–6,and 6–10 mm(both P<0.05);At 3mo postoperatively,the FS-LASIK Xtra group is higher than that of the FS-LASIK group in the ranges of 0–2 and 2–6 mm(P<0.05).At 6mo postoperatively,there were no statistically significant differences in corneal densitometry between the FS-LASIK group and the FS-LASIK Xtra group in different diameter ranges(all P>0.05).CONCLUSION:There is an increase in internal corneal densitometry during the early postoperative period after FS-LASIK Xtra for correction of high myopia.However,the densitometry values decreased to the level of conventional FS-LASIK at 6mo after surgery,with the most significant changes observed in the superficial central zone.

Effect of Shrinkage Reducing Agent and Steel Fiber on the Fluidity and Cracking Performance of Ultra-High Performance Concrete

Due to the low water-cement ratio of ultra-high-performance concrete(UHPC),fluidity and shrinkage cracking are key aspects determining the performance and durability of this type of concrete.In this study,the effects of different types of cementitious materials,chemical shrinkage-reducing agents(SRA)and steel fiber(SF)were assessed.Compared with M2-UHPC and M3-UHPC,M1-UHPC was found to have better fluidity and shrinkage cracking performance.Moreover,different SRA incorporation methods,dosage and different SF types and aspect ratios were implemented.The incorporation of SRA and SF led to a decrease in the fluidity of UHPC.SRA internal content of 1%(NSRA-1%),SRA external content of 1%(WSRA-1%),STS-0.22 and STE-0.7 decreased the fluidity of UHPC by 3.3%,8.3%,9.2%and 25%,respectively.However,SRA and SF improved the UHPC shrinkage cracking performance.NSRA-1%and STE-0.7 reduced the shrinkage value of UHPC by 40%and 60%,respectively,and increased the crack resistance by 338%and 175%,respectively.In addition,the addition of SF was observed to make the microstructure of UHPC more compact,and the compressive strength and flexural strength of 28 d were increased by 26.9%and 19.9%,respectively.

Remaining oil distribution characteristics in an oil reservoir with ultra-high water-cut

An accurate mapping and understanding of remaining oil distribution is very important for water control and stabilize oil production of mature oilfields in ultra-high water-cut stage.Currently,the Tuo-21 Fault Block of the Shengtuo Oilfield has entered the stage of ultra-high water cut(97.2%).Poor adaptability of the well pattern,ineffective water injection cycle and low efficiency of engineering measures(such as workover,re-perforation and utilization of high-capacity pumps)are the significant problems in the ultra-high water-cut reservoir.In order to accurately describe the oil and water flow characteristics,relative permeability curves at high water injection multiple(injected pore volume)and a semiquantitative method is applied to perform fine reservoir simulation of the Sand group 3e7 in the Block.An accurate reservoir model is built and history matching is performed.The distribution characteristics of remaining oil in lateral and vertical directions are quantitatively simulated and analyzed.The results show that the numerical simulation considering relative permeability at high injection multiple can reflect truly the remaining oil distribution characteristics after water flooding in an ultrahigh water-cut stage.The distribution of remaining oil saturation can be mapped more accurately and quantitatively by using the‘four-points and five-types’classification method,providing a basis for potential tapping of various remaining oil types of oil reservoirs in late-stage of development with high water-cut.