Degenerative myopia: mechanical theories revisited

The article discusses the early abandonment of mechanical theories about eye enlargement in degenerative myopia at the turn of the 20th century.At that time,the number of theories about myopia grew unrestricted,but with scant support from the experimental field.The mechanical theories vanished as a new wave of metabolism-based theories appeared,propelled by the huge advances in molecular biology.Modern techniques allow reconsidering those theories and to put them to test with higher confidence.

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.

ATP-binding cassette transporters as possible targets for the intervention of neurodegenerative diseases

ATP-binding cassette(ABC)transporters are ubiquitous membrane-bound proteins that are responsible for the translocation of a broad spectrum of substrates across cellular membranes,including lipids,amino acids,nucleosides,sugars,and xenobiotics.Interestingly,ABC transporters are highly expressed in the brain.While their functions in the brain still need to be elucidated,several members are implicated in the pathogenesis of neurodegenerative diseases,including Alzheimer’s disease(AD),Parkinson’s disease(PD),and frontotemporal dementia.In this perspective,we will review current knowledge of ABC transporters in the central nervous system in terms of physiological functions and pathology in neurodegeneration.Furthermore,we will explore the possibilities of ABC transporters as potential targets in the development of therapeutics for neurodegenerative diseases.

Advancements in personalized stem cell models for aging-related neurodegenerative disorders

Neurodegenerative diseases(NDDs)are a class of disorders characterized by the gradual loss or malfunction of specific cell populations in the nervous system,which can be triggered by genetic or environmental factors.As a result,patients often experience a decline in mobility,sensation,memory,and cognition,which can ultimately lead to a fatal outcome.The global incidence of NDDs,including Alzheimer’s disease,Parkinson’s disease,Huntington’s disease,amyotrophic lateral sclerosis(ALS),and multiple sclerosis,is increasing.

Inducing neuronal regeneration and differentiation via the BDNF/ TrkB signaling pathway: a key target against neurodegenerative diseases?

Brain-derived neurotrophic factor(BDNF)is one of the neurotrophins,a specific polypeptide growth factor,which plays a crucial role in the proliferation,differentiation,survival,and death of neurons and non-neuronal cells.It is not only essential to maintain the balance between death on one side and survival of neurons on the other,but also it mediates additional higher-order activities such as learning,memory,and behavior.It is initially synthesized as a precursor protein,proBDNF,that can be secreted as it is or it can be cleaved intracellularly by furin and proconvertases,or extracellularly by extracellular proteases such as matrix metalloprotease-9 and matrix metalloprotease-2,or plasmin to give mature BDNF.

Stress granules: friend or foe in neurodegenerative disorders?

Neurodegenerative diseases,such as Alzheimer’s disease,Parkinson’s disease,and amyotrophic lateral sclerosis,despite the diversity in clinical symptoms,share a striking feature at the cellular level:the accumulation of insoluble aggregates of misfolded proteins that are sequestered in intraneuronal inclusion bodies.Besides mutations in disease-associated proteins that render them aggregation-prone,the decline of protein homeostasis(i.e.proteostasis)with aging is also believed to be a contributing factor to the accumulation of protein aggregates.

Current controversies in glia-to-neuron conversion therapy in neurodegenerative diseases

Loss of neurons and disruption of neural circuits are associated with many neurological diseases,including neurodegenerative diseases and mental disorders.The most prevalent pathological feature of neurodegenerative diseases is the aggregate loss of certain neuronal populations.For example,the loss of dopamine(DA)neurons in the substantia nigra pars compacta has been defined as a pathological hallmark of Parkinson’s disease(PD;Kamath et al.,2022).

Advances in non-invasive imaging of proteinopathies in animal models of neurodegenerative diseases

Neurodegenerative diseases,including Alzheimer's disease(AD),frontotemporal dementia,Parkinson's disease,and dementia with Lewy bodies,represent tremendous unmet clinical needs.A common feature of these diseases is the aberrant cerebral accumulation of pathological protein aggregates,affecting selectively vulnerable circuits in a disease-specific pattern.Earlier studies have established a relationship between abnormal aggregation and neuronal dysfunction or loss,suggesting multifactorial pathogenesis mechanisms in these neurodegenerative disorders.

Mitochondrial therapeutics and mitochondrial transfer for neurodegenerative diseases and aging

Mitochondrial dysfunction and neurodegeneration:Progressive neurodegenerative diseases affect a significant proportion of the population;in a single year,there are as many as 276 million disabilities and 9 million deaths as a result of neurological diseases.

Cognition and movement in neurodegenerative disorders:a dynamic duo

People with neurodegenerative disorders often experience problems across a variety of functional domains,including cognition,movement,and psychosocial functioning.The classification of these disorders is based on the phenotypical manifestations that represent the most prominent clinical features.For example,Parkinson's disease and Huntington's disease are typically regarded as movement disorders,whereas Alzheimer's disease(AD) and other dementias are regarded as cognitive disorders.

Exploring the synergy of the eyebrain connection:neuromodulation approaches for neurodegenerative disorders through transcorneal electrical stimulation

The connection and interaction between the eye and the brain are crucial to understanding brain disorders(Marchesi et al.,2021).Both the eye and the brain have a limited regenerative capacity as there are few progenitor cells,and nerve cells do not replicate.Hence,neurodegeneration implicates irreversible damage to the central nervous system,as observed in several neurodegenerative diseases(Marchesi et al.,2021).

Microglial dysfunction and genetic risk for neurodegenerative disease

Neurodegenerative disorders such as Alzheimer's and Parkinson's diseases a re increasing in prevalence as world populations age.While tremendous progress has been made,our understanding of the mechanisms that underlie the development of these diseases remains far from com plete.More troubling,despite the growing emotional and financial toll being to ken by neurodegenerative disorders,existing treatment options are limited almost exclusively to those that help manage symptoms but that lack the ability to alter the progression of the disease(Liu et al.,2022).

New insights into astrocyte diversity from the lens of transcriptional regulation and their implications for neurodegenerative disease treatments

Astrocytes are a major glial cell type in the central nervous system,and they provide trophic and metabolic support to neurons.In addition to these roles,they play crucial roles in modulating synaptic functions,development,and pruning(Brandebura et al.,2023).Astrocytes become reactive(activated)by undergoing morphological,molecular,and functional alterations in response to neuropathology such as in injuries and neurodegenerative diseases(NDs)(Escartin et al.,2021).

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.

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.

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.

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.

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.

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.