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.

Time trends in myopia and high myopia prevalence in young university adults in China

AIM:To investigate time trends in myopia and high myopia prevalence over 6y among young university adults in China.METHODS:This is a 6-year series cross-sectional study from 2016 to 2021.Totally 4910 freshmen were enrolled and completed a questionnaire concerning age,gender,and disease history.Students with eye diseases were excluded after a detailed eye examination.The refractive status was measured by non-cycloplegic objective refraction and ocular parameters were measured by Lenstar 900.The examination followed the same protocol each year.Trends over time in myopia and high myopia prevalence,as well as ocular biometry parameters,were analyzed.RESULTS:From 2016 to 2021,the axial length(AL)and corneal radius(CR)increased significantly(P=0.002 for AL;P=0.04 for CR).However,the spherical equivalent(SE)and the ratio of axial length to the corneal radius(AL/CR)did not change significantly(P=0.59 for SE;P=0.24 for AL/CR).The frequency of AL≥26.0 mm increased from 26.6%in 2016 to 29.3%in 2021(P=0.05 for trend).The prevalence of myopia and high myopia did not change significantly in our study(P≥0.18).Compared to a similar cross-sectional study conducted 10 years ago,the prevalence of myopia decreased significantly(94.9%vs 91.8%,P<0.001).Whereas the prevalence of high myopia increased largely(18.12%vs 27.6%,P<0.001).CONCLUSION:The prevalence of high myopia increases in young university adults during 10y period.Myopia control should begin earlier in childhood.However,these interventions are still needed for high myopia even in young adulthood.

Effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization in high myopia mice

AIM:To evaluate effects of endogenous dopamine induced by low concentration atropine eye drops on choroidal neovascularization(CNV)in high myopia mice.METHODS:The C57BL/6J mice were deprived of the right eye for 4wk,and the high myopia was diagnosed by optometry,the diopter was less than-6.00 D,and CNV was induced by 532 nm laser.The changes of dopamine D1 receptor(DRD1),dopamine D2 receptor(DRD2),and vascular endothelial growth factor A(VEGFA)were detected by Western blot technology at 0.5,1,2h,and 7d after 0.01%,0.05%,and 0.1%atropine eye drops,respectively,the area of CNV was measured.RESULTS:Significant increases were observed on the expression of DRD2 in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).Significant decreases were observed on the expression of DRD1 and VEGFA in mouse high myopia model at 0.5,1,2h,7d with 0.05%and 0.1%atropine eye drops(P<0.05).The area of CNV induced by laser in the drug-treated group was significantly smaller than that in the control group,and the higher the concentration,the more significant the inhibitory effect(P<0.05).CONCLUSION:The 0.01%,0.05%,0.1%atropine eye drops can decrease the level of VEGFA and inhibit high myopia CNV indirectly by up-regulating the level of DRD2 and down-regulating the level of DRD1,and the effect of 0.05%and 0.1%atropine eye drops is more significant.

Changes of optic nerve head microcirculation in high myopia

AIM:To analyze the correlation of age,spherical equivalent(SE),and axial length(AL)with the microcirculation of optic nerve head(ONH)in high myopia(HM).METHODS:In this cross-sectional clinical study,164 right eyes were included.Optical coherence tomography angiography(OCTA)was used to detect ONH vessel density.Eyes were classified based on age,SE,and AL.Groups of Age1,Age2,and Age3 were denoted for age classification(Age1<20y,20y≤Age2<30y,Age3≥30y);Groups SE1,SE2,and SE3 for the SE classification(-9≤SE1<-6 D,-12≤SE2<-9 D,SE3<-12 D);Groups AL1,AL2,AL3,and AL4 for the AL classification(AL1<26 mm,26≤AL2<27 mm,27≤AL3<28 mm,AL4≥28 mm).RESULTS:No significant difference was observed in vessel density among the Age1,Age2,and Age3 groups(all P>0.05)and the SE1,SE2,and SE3 groups(all P>0.05).No significant difference was observed in the intrapapillary vascular density(IVD)among AL1,AL2,AL3,and AL4 groups(P>0.05).However,a significant decrease was found in the peripapillary vascular density(PVD)in the AL1,AL2,AL3,and AL4 groups(F=3.605,P=0.015),especially in the inferotemporal(IT;F=6.25,P<0.001),temporoinferior(TI;F=2.865,P=0.038),and temporosuperior(TS;F=6.812,P<0.001)sectors.The IVD was correlated with age(r=-0.190,P<0.05)but not with SE or AL(P>0.05).The PVD was correlated with AL(r=-0.236,P<0.01)but not with age or SE(P>0.05).CONCLUSION:With the increase of AL,the IVD remains stable while the PVD decreases,especially in the three directions of temporal(IT,TI,and TS).The main cause of microcirculation reduction may be related to AL elongation rather than an increase in age or SE.

Value of optical coherence tomography measurement of macular thickness and optic disc parameters for glaucoma screening in patients with high myopia

BACKGROUND The basic method of glaucoma diagnosis is visual field examination,however,in patients with high myopia,the diagnosis of glaucoma is difficult.AIM To explore the value of optical coherence tomography(OCT)for measuring optic disc parameters and macular thickness as a screening tool for glaucoma in patients with high myopia.METHODS Visual values(contrast sensitivity,color vision,and best-corrected visual acuity)in three groups,patients with high myopia in Group A,patients with high myopia and glaucoma in Group B,and patients with high myopia suspicious for glaucoma in Group C,were compared.Optic disc parameters,retinal nerve fiber layer(RNFL)thickness,and ganglion cell layer(GCC)thickness were measured using OCT technology and used to compare the peri-optic disc vascular density of the patients and generate receiver operator characteristic(ROC)test performance curves of the RNFL and GCC for high myopia and glaucoma.RESULTS Of a total of 98 patients admitted to our hospital from May 2018 to March 2022,totaling 196 eyes in the study,30 patients with 60 eyes were included in Group A,33 patients with 66 eyes were included in Group B,and 35 patients with 70 eyes were included in Group C.Data were processed for Groups A and B to analyze the efficacy of RNFL and GCC measures in distinguishing high myopia from high myopia with glaucoma.The area under the ROC curve was greater than 0.7,indicating an acceptable diagnostic value.CONCLUSION The value of OCT measurement of RNFL and GCC thickness in diagnosing glaucoma in patients with high myopia and suspected glaucoma is worthy of development for clinical use.

Evolution and trends of high myopia research from 2002 to 2021: a scientometric analysis

Background:Research on high myopia has gradually formed a complex network of knowledge,but a panorama of evolutionary trends is lacking.By conducting a scientometric analysis,we can gain a deeper understanding of the development and evolution of this field.Methods:The global literature on high myopia published from 2002 to 2021 was extracted from the Science Citation Index Expanded in the Web of Science Core Collection.Microsoft Excel,VOSviewer,and CiteSpace were used to analyse and visualize the bibliometric data.Publication-related information,including countries,journals,authors,citations,subject categories,and its’time trends,was analysed.Results:A total of 4,226 included publications showed an annually increasing trend during the past 20 years.The high myopia research hotspots were refractive error correction,epidemiology,ocular biometry,drug and laser treatment of myopic fundus lesions,and surgical treatment of myopic fundus lesions.Cocitation analysis showed that high myopia genetics and myopic fundus lesion research were the research frontiers.A total of 116 disciplines were involved in high myopia research.Ophthalmology(n=3,338)was the most dominant subject category.Engineering(betweenness centrality=0.65)was the discipline with the most obvious bridge role.Science&technology—other topics(burst years:2015–2021;strength=14.88)had the greatest strength as of 2021,which was the hottest subject category.Conclusions:High myopia genetics and myopic fundus lesion research showed a potential for breakthroughs.Medical-engineering cross-innovation is a cutting-edge technology trend.

Rhegmatogenous retinal detachment in highly myopic eyes with implantable collamer lens

AIM:To investigate the clinical characteristics,treatment methods and outcomes of rhegmatogenous retinal detachment(RRD)in highly myopic eyes with implantable collamer lens(ICL).METHODS:High myopia patients who received treatment for nontraumatic RRD after ICL implantation surgery at the Retinal Department of Zhongshan Ophthalmic Center from Jan 2018 to Dec 2022 were reviewed.Comprehensive ophthalmologic examinations including visual acuity measurement and digital fundus photography were performed in each patient.RESULTS:A total of nine RRD eyes from nine patients who received V4c-ICL implantation were included.The mean time from ICL implantation surgery to the diagnosis of RRD was 32.44±22.56mo(range,1-60mo).At the initial visit for RRD,giant retinal tear(GRT),horseshoe tear,simple round hole,and horseshoe tear combined with round hole were detected in 3,3,2,and 1 eye(s),respectively,with maculaoff in eyes.Eight patients received surgical treatment,and one patient was treated by retinal laser photocoagulation alone.The ICL was preserved in 7 eyes.At the last followup,the mean best corrected visual acuity(BCVA)improved significantly from 1.76±1.06 logMAR at presentation to 0.81±1.01 logMAR(P=0.035),and no case of recurrent retinal detachment was found.CONCLUSION:The morphological presentation of retinal breaks is diverse in this study.The ICL can be preserved in most cases during the course of retinal detachment repair surgery in our data,companied with acceptable visual and anatomical outcomes.

Long-term vision-threatening complications of phakic intraocular lens implantation for high myopia

AIMTo report the long-term vision-threatening complications in patients who underwent phakic intraocular lens (pIOLs) implantation for high myopia.

Diagnostic ability of ganglion cell complex thickness to detect glaucoma in high myopia eyes by Fourier domain optical coherence tomography

AIM：To evaluate the ability of macular ganglion cell complex（GCC） thickness using Fourier domain optical coherence tomography（FD-OCT） to detect glaucoma in highly myopic eyes.METHODS：Cross-sectional study.A total of 114 participants,consecutively were enrolled.Macular GCC thickness and peripapillary retinal nerve fiber layer（RNFL） thickness were obtained with RTVue FD-OCT.Receiver operating characteristics curves were constructed for each measurement parameter,and areas under the curves（AUCs） were compared.RESULTS：Both the average GCC and average RNFL thickness showed negative correlations with axial length（rGCC=-0.404,P=0.001;rRNFL=-0.561,P〈0.001）.The largest AUCs from GCC,and RNFL parameters were 0.968 [global loss volume（GLV）],and 0.855（average RNFL）,respectively.GLV was significantly better for detecting high myopic glaucoma than average RNFL（P〈0.001）.CONCLUSION：Macular GCC thickness has higher diagnostic power than peripapillary RNFL thickness to discriminate glaucoma patients from non-glaucoma subjects in high myopia.

Comparison axial length measurements from three biometric instruments in high myopia

AIM： To compare the axial lengths （ALs） measured with Lenstar, IOLMaster and A-scan contact ultrasound （Ultrasound） in normal and high myopia （HM）. METHODS： Eighty-four normal eyes and 49 HM eyes were included. Three consecutive measurements were performed on each eye in the following order： Lenstar, IOLMaster, and Ultrasound. The repeatabilities of the AL measurements for each instrument were assessed by calculating the pooled coefficients of variation （CVs） of 18 eyes in each group. Comparisons between the HM and normal groups were made with independent sample t-tests. The inter-device agreements were evaluated with Bland-Altman analyses and paired two-tailed t-tests. RESULTS： For normal group, the CVs of the AL measurements taken with the Lenstar, IOLMaster and Ultrasound were 0.001%, 0.01% and 0.14%, respectively. The corresponding CVs for the HM group were 0.005%, 0.02% and 0.15%, respectively. There was significant difference between the Lenstar and the IOLMaster in normal group （P=0.031） but not in HM group （n=0.100）. In the two groups, the Lenstar and the IOLMaster produced higher values than did the Ultrasound （all P〈 0.001）. All three instruments exhibited good agreement in terms of AL values. For the intraocular lens （IOL） power calculation using SRK II formula, the Lenstar and the IOLMaster showed 0.5 D higher than Ultrasound in both groups （all P〈0.001）. No significant difference existed between the Lenstar and the IOLMaster for the IOL power calculation in both normal （n=0.474） and HM group （P= 0.103）. CONCLUSION： The three devices exhibited excellent intra-visit repeatabilities in the AL measurements. The AL and IOL power difference between partial coherence interferometry and ultrasound instruments should be noticed.

The association of lumican polymorphisms and high myopia in a Southern Chinese population

AIM：To investigate the correlation between lumican（LUM）gene and high myopia in a Southern Chinese population.METHODS：The study comprised of 95 high myopia patients with a spherical equivalent≤-6.5 diopters（D）.The control group recruited 95 individuals with a spherical equivalent ranging from-0.5 D to＋0.5 D.Direct sequencing was used to detect the single nucleotide polymorphisms（SNPs）of LUM gene in coding region.Genotype distributions were tested for Hardy-Weinberg disequilibrium.Genotypic and allelic frequencies were analyzed through Chi-square test or Fisher’s exact test.RESULTS：We identified 3 SNPs of the LUM gene：LUM c.32（rs577456426）,LUM c.507（rs17853500）and LUM c.849（rs181915277）.Among the three SNPs,the genotype and allele frequencies of rs17853500 showed a significant difference between patients and control subjects（P〈0.05）.However,there were no significant differences in rs181915277and rs577456426 between the two groups（P〉0.05）.CONCLUSION：LUM c.507 polymorphism may be a risk factor for the pathogenesis of high myopia in the Southern Chinese population.

High myopia as a risk factor in primary open angle glaucoma

Glaucoma, one of the leading causes of irreversible blindness in the adult population worldwide, is a progressive optic neuropathy. Primary open angle glaucoma (POAG) is the most commonly reported type of glaucoma in population based prevalence studies worldwide. Elevated intraocular pressure is a well-known major risk factor for POAG. In addition, there is growing evidence that other risk factors like age, gender, race, refractive error, heredity and systemic factors may play a role in glaucoma pathogenesis. Many studies found that high myopia has been associated with POAG, however, direct and convincing evidences are still lacking. The aim of this review is to summarize the evidences implicating high myopia as a risk factor in the pathogenesis of POAG.

Association between lumican gene-1554 T/C polymorphism and high myopia in Asian population:a meta-analysis

AIMTo investigate the association between lumican gene -1554 T/C polymorphism and high myopia susceptibility.

Genetic association of COL1A1 polymorphisms with high myopia in Asian population: a Meta-analysis

AIM: To comprehensively evaluate the potential association of COL1A1 polymorphisms with high myopia by a systematic review and Meta-analysis. METHODS: All association studies on COL1A1 and high myopia reported up to June 10, 2014 in PubMed, Embase, Web of Science, and the Chinese Biomedical Database were retrieved. Odds ratios (ORs) and 95% confidence intervals (95% CIs) were analyzed for single-nucleotide polymorphisms (SNPs) using fixed- and random - effects models according to between-study heterogeneity. Publication bias analyses were conducted by Eggers test. RESULTS: A total of four studies from reported papers were included in this analysis. The Meta-analyses for COL1A1 rs2075555, composed of 2304 high myopia patients and 2272 controls, failed to detect any significant association with high myopia. A total of 971 cases and 649 controls were tested for COL1A1 rs2269336. The association of COL1A1 rs2269336 with high myopia was observed in recessive model (CC vs CG+GG, P = 0.03) and in heterozygous model (CG vsGG, P = 0.04), but not in other models. CONCLUSION: This Meta-analysis shows that COL fill rs2269336 (CC vs CG +GG) affects individual susceptibility to high myopia, whereas there is no association detected between SNPs rs2075555 and high myopia. Given the limited sample size, further investigations including more ethnic groups are required to validate the association.

Five-year results of refractive outcomes and visionrelated quality of life after SMILE for the correction of high myopia

AIM:To evaluate the long-term visual,refractive outcomes and vision-related quality of life after small incision lenticule extraction(SMILE)for the correction of high myopia.METHODS:Thirty patients(60 eyes)with high myopia who underwent SMILE more than 5y were selected as the SMILE group.Another 30 high myopia patients(60 eyes)who had worn corrective spectacles for more than 5y were selected as the control group.In SMILE group,the postoperative follow-up time were 3,6 mo,1 and 5y.Uncorrected distance visual acuity(UDVA),corrected distance visual acuity(CDVA),spherical equivalent(SE),and ocular axial length(AL)were analyzed.The Chinese version of the National Eye Institute Visual Function Questionnaire-25(CHI-NEI-VFQ-25)was used to evaluate the vision-related quality of life in the SMILE group and the control group.RESULTS:In SMILE group,the mean preoperative SE was-7.29±0.87 D(range-6.00 to-9.125 D).At 5-year follow up,the efficacy index and safety index of SMILE were 1.09±0.18 and 1.19±0.12,respectively.Five years postoperatively,44 eyes(73%)obtained a visual acuity of 20/20 or better.There were no eyes with CDVA loss of one or more Snellen lines.Forty-nine eyes(82%)and 57 eyes(95%)were within±0.50 and±1.00 D of attempted correction at 5-year follow-up,respectively.Forty-eight eyes(80%)had astigmatism<0.50 D at 5-year followup.The postoperative mean SE values at 3,6 mo,1,and 5y were 0.11±0.44,0.07±0.45,-0.02±0.41,and-0.15±0.46 D,respectively.No significant change was observed in the ocular AL from before operation to 5y postoperatively(26.08±0.96 mm vs 26.01±0.94 mm,P=0.068).Compared to the control group,the SMILE group showed a significantly higher total score on the CHI-NEI-VFQ-25(90.14 vs 81.43,P<0.001).CONCLUSION:In the present study,in a long-term follow-up we demonstrate that correcting high myopia with SMILE is safe,effective,and predictable.Vision-related quality of life after SMILE is better in the SMILE group than in the control group who wore corrective spectacles.

Measurements of the parapapillary atrophy area and other fundus morphological features in high myopia with or without posterior staphyloma and myopic traction maculopathy

AIM:To investigate the affecting factors of parapapillary gamma and delta zones and other fundus morphological features in high myopia.METHODS:Seventy high myopia patients were included in this retrospective observational study and 47 patients were female.Patients were divided into three groups:no posterior staphyloma(no PS),PS with myopic traction maculopathy(PS with MTM),and PS without MTM using 3-dimensional magnetic resonance imaging and optical coherence tomography.MTM patients were fur ther classified into three types[epiretinal membrane,macular hole,and macular retinoschisis(MRS)].Diameters of the gamma and delta zones were measured among other morphometric variables using fundus photographs.RESULTS:Of the 70 individuals(127 eyes),the mean age was 57.46±13.56y.In univariate analysis,morphological features changed most dramatically in PS with MTM patients,who had the largest gamma zone diameters,the largest disk-fovea distance(DFD)and disk-fovea angle,and the smallest angle kappa and vertical distance of temporal arterial arcade.However,their horizontal delta zone diameter was smaller than in the patients with PS yet without MTM.In multivariate analysis,with axial length(AL)and age adjusted,the horizontal diameter in the delta zone of the PS without MTM group was still significantly larger than in the PS with MTM group(P=0.024).Comparing the three subtypes of MTM patients,the diameters of the gamma zone and DFD in MRS group were the largest.CONCLUSION:The characteristics of the gamma and delta zones change inconsistently in different stages of high myopia.These changes may be associated with anatomical changes caused by local traction.Factors such as PS,AL and age play an important role.These findings may provide a hint about the pathogenesis of traction in high myopia.

Trends in research related to high myopia from 2010 to 2019:a bibliometric and knowledge mapping analysis

AIM:To evaluate the global trends in and explore hotspots of high myopia(HM)research.METHODS:This bibliometric analysis was used to reveal the publication trends in HM research field based on the Web of Science Core Collection(WoSCC).VOSviewer version 1.6.13 software was used to analyze the data and construct a knowledge map including the yearly publication number,journals,countries,international collaborations,authors,research hotspots,and intellectual base in HM.RESULTS:The search engine found 3544 peer-reviewed publications on HM between 2010 and 2019,and the yearly research output substantially elevated over the past decade.China is the top publishing country,and Sun Yatsen University was the most active academic institution.Jonas JB is the top publishing scientist,and Investigative Ophthalmology and Visual Science(IOVS)was the most productive journal.The highest cited references mainly focused on epidemiology and management.The keywords formed 6 clusters:1)refractive surgery;2)etiology and clinical characteristics;3)the mechanism of eye growth;4)management for myopic maculopathy;5)vitrectomy surgical treatment;6)myopia-associated glaucoma-like optic neuropathy.CONCLUSION:The evaluation of development trends based on the data extracted from WoSCC can provide valuable information and guidance for ophthalmologists and public health researchers to improve management procedures in HM field.

Abnormal resting-state functional network centrality in patients with high myopia： evidence from a voxel-wise degree centrality analysis

AIM： To investigate the functional networks underlying the brain-activity changes of patients with high myopia using the voxel-wise degree centrality（DC） method.METHODS： In total, 38 patients with high myopia（HM）（17 males and 21 females）, whose binocular refractive diopter were-6.00 to-7.00 D, and 38 healthy controls（17 males and 21 females）, closely matched in age, sex, and education levels, participated in the study. Spontaneous brain activities were evaluated using the voxel-wise DC method. The receiver operating characteristic curve was measured to distinguish patients with HM from healthy controls. Correlation analysis was used to explore the relationship between the observed mean DC values of the different brain areas and the behavioral performance.RESULTS： Compared with healthy controls, HM patients had significantly decreased DC values in the right inferior frontal gyrus/insula, right middle frontal gyrus, and right supramarginal/inferior parietal lobule（P〈0.05）. In contrast, HM patients had significantly increased DC values in the right cerebellum posterior lobe, left precentral gyrus/postcentral gyrus, and right middle cingulate gyrus（P〈0.05）. However, no relationship was found between the observed mean DC values of the different brain areas and the behavioral performance（P〉0.05）.CONCLUSION： HM is associated with abnormalities in many brain regions, which may indicate the neural mechanisms of HM. The altered DC values may be used as a useful biomarker for the brain activity changes in HM patients.

Clinical outcomes of transepithelial photorefractive keratectomy versus femtosecond laser assisted keratomileusis for correction of high myopia in South Egyptian population

AIM: To evaluate the safety and efficacy of transepithelial photorefractive keratectomy(t-PRK) with adjuvant mitomycin C(MMC) versus femtosecond laser assisted keratomileusis(Femto-LASIK) in correction of high myopia.METHODS: Prospective randomized comparative study including 156 eyes of 156 patients with high myopia and a spherical equivalent refraction(SER) <-6.00 D. They were divided randomly into two groups: Group A included 72 eyes treated with t-PRK with adjuvant MMC and Group B included 84 eyes treated with Femto-LASIK. Visual acuity, SER, corneal topography, pachymetry and keratometry were assessed for 12 mo postoperatively.RESULTS: The preoperative mean SER was-8.86±1.81 and-9.25±1.70 D in t-PRK MMC group and Femto-LASIK respectively(P=0.99) which improved to-0.65±0.43 D and-0.69±0.50 D at 12 mo follow up. Mean SER remained stable during the 12 mo of follow-up, with no statistically significant difference between the two groups(P=0.64). In t-PRK MMC group, only six eyes needed retreatment after six months of follow up. And two eyes showed haze(one reversible haze grade 2, while the other had dense irreversible haze grade 4).CONCLUSION: t-PRK MMC provides safe and satisfactory visual outcomes and acceptable risk as Femto-LASIK in patients with high myopia.