Aberrant TGF-β1 signaling activation by MAF underlies pathological lens growth in high myopia

Polystyrene nanoplastics chronic exposure cause zebrafish visual neurobehavior toxicity through TGFβ-crystallin axis

The ubiquitous presence of micro-and nanoplastics (MNPs) in the environment and everyday products has attracted global attention for their hazardous risks. However, the effects and underling mechanisms of MNPs chronic exposure on behavioral/visual changes of the adult and offspring remain unclear. The present study investigated the impact of polystyrene (PS) nanoplastics of 80, 200 and 500 nm diameters on zebrafish visual behaviors at an environmentally relevant concentration of 0.1 mg/L. Exposure to PS resulted in zebrafish hyperactivity, enhanced aggression, compacted shoaling and less sociability, and especially suppressed the adult optokinetic response (OKR) and offspring larval phototactic behavior, with the 500 nm PS being the most detrimental. Histopathological analysis showed 500 nm PS caused significant structural damage to the retina's pigment epithelium (RPE), photoreceptor cells (PRC), and crystalline lens. Fluorescence observation found PS accumulation in retinal layers correlated with reduced oligodendrocyte transcription factor 2 (Olig2) in optic nerve. Further transcriptomic analysis of the adult eye tissue revealed that 500 nm PS affected the transforming growth factor β (TGFβ) and phototransduction signaling pathways, dysregulated visual perception and lens development, potentially leading to dysopia in zebrafish. Specifically, TGFβ and its regulated-extracellular matrix/inflammatory factors and crystallin genes were increased, but the visual perception genes were decreased, suggesting the TGFβ-crystallin axis disorders contribute to the eye dysfunction induced by PS exposure. Collectively, our results provide new evidence revealing the molecular mechanisms of PS-induced visual toxicity and neurobehavioral changes highlighting that MNPs may pose a risk to vision health.

Crosstalk between signaling pathways (Rho/ROCK, TGF-β and Wnt/β-Catenin Pathways/ PI3K-AKT-mTOR) in Cataract: A Mechanistic Exploration and therapeutic strategy

Cataract are a leading cause of visual impairment that is characterized by clouding or lens opacification of the healthy clear lens of the eye or its capsule. It can be classified based on their etiology and clinical presentation such as congenital, age-related, and secondary cataracts. Clinically, it may be further classified as a cortical or nuclear cataract. Cortical cataracts are responsible for opacification of the lens cortex, while nuclear cataracts cause age-related degeneration of the lens nucleus. This review aims to explore the molecular mechanism associated with various signaling pathways underlying cataract formation. Additionally, explore the potential therapeutic strategies for the management of cataracts. A comprehensive literature search was performed utilizing different keywords such as cataract, pathogenesis, signaling pathways, therapeutic approaches, RNA therapeutics, and surgery. Electronic databases such as PubMed, Google Scholar, Springer Link, and Web of Science were used for the literature search. The cataract formation is responsible for protein aggregation, primarily of γ-crystallin, and causes disruptions in signaling pathways. Key pathways include Rho/ROCK, TGF-β, Wnt/β-catenin, NF-κB, and PI3K-AKT-mTOR. Signaling pathways governing lens epithelial cell differentiation and epithelial-to-mesenchymal transition (EMT) are essential for maintaining lens transparency. Disruptions in these pathways, often caused by genetic mutations in genes like MIP, TDRD7, PAX6, FOXE3, HSF4, MAF, and PITX3 lead to cataract formation. While surgical intervention remains the primary treatment, pharmacological therapies and emerging RNA-based strategies offer promising strategies for the prevention and management of cataracts. A deeper understanding of the underlying molecular mechanisms is essential to develop innovative therapeutic strategies and improve the quality of life for individuals affected by cataracts.

Capsular Tension Ring Implantation for Intraocular Lens Power Calculation in Highly Myopic Eyes: Secondary Analysis of a Randomized Clinical Trial

Importance

Capsular tension ring (CTR) implantation has been shown to reduce intraocular lens (IOL) decentration and tilt in high myopia. However, the effect of CTR implantation in highly myopic eyes on IOL power calculation remains unclear, particularly in new-generation formulas.

Objective

To evaluate the influence of CTR implantation on IOL power calculation in highly myopic eyes.

Design, Setting, and Participants

This is a prespecified secondary analysis of outcomes of a randomized clinical trial conducted between November 2021 and September 2023 at the Zhongshan Ophthalmic Center in Guangzhou, China. Cataract patients with an axial length (AL) of 26 mm or longer were enrolled and stratified into 3 strata based on AL (stratum 1: AL 26-<28 mm; stratum 2: AL 28-<30 mm; stratum 3: AL ≥30 mm).

Interventions

Participants were stratified based on AL and randomized to the CTR group (a C-loop IOL combined with a CTR) or the control group (only a C-loop IOL) within each stratum.

Main Outcomes and Measures

Predictive outcomes of 6 new-generation formulas and 4 traditional formulas were evaluated. The arithmetic and absolute prediction error (PE) and the percentages of eyes within ±0.25 diopter (D), ±0.50 D, ±0.75 D, and ±1.00 D of PE were analyzed.

Results

A total of 186 eyes of 186 participants were randomized into the CTR group (93 eyes [50%]) or control group (93 eyes [50%]). Excluding a withdrawal case and 24 eyes with best-corrected visual acuity less than 20/40, 80 eyes in the CTR group (86.0%) and 81 eyes in the control group (87.1%) were analyzed. Of 161 participants analyzed, overall mean (SD) participant age was 56.7 (10.5) years, and 100 participants (62.1%) were female. No differences were observed in arithmetic PE between the CTR and control groups in any strata. The CTR group showed smaller absolute PE in all new-generation formulas and higher percentage of PE within ±0.50 D in the Emmetropia Verifying Optical 2.0, Hoffer QST, LISA, and Pearl-DGS formulas only for eyes with an AL of 30 mm or longer compared with the control group. In traditional formulas, no differences were observed between the 2 groups in any strata.

Conclusions and Relevance

In this secondary analysis, CTR implantation in highly myopic eyes did not affect the target refraction and can improve the prediction accuracy of new-generation IOL calculation formulas in eyes with AL of 30 mm or longer. These findings support use of CTR implantation in eyes with an AL of 30 mm or longer.

Trial Registration

ClinicalTrials.gov Identifier: NCT05161520.

TGF-β1-induced m6A modifications accelerate onset of nuclear cataract in high myopia by modulating the PCP pathway

High myopia is an important cause of visual impairment worldwide, characterized by early-onset nuclear cataracts, whose underlying mechanisms remain largely unexplained. Here, we identify conspicuously polarized and compacted lens fiber alignment, along with a simultaneous rise in N6-methyladenosine (m6A) modifications in patients with highly myopic cataracts (HMC), which is confirmed to be induced by elevated transforming growth factor-β1 (TGF-β1) in lens. Mechanistically, methyltransferase METTL3 and m6A reader insulin-like growth factor 2 mRNA binding protein 3 synergistically enhance planar cell polarity (PCP) signaling by affecting mRNA stability of dishevelled 2. This, in turn, alters proliferation, migration, and polarity formation of human lens epithelial cells. Moreover, Mettl3 conditional knockdown in mice leads to disrupted lens fiber arrangement and alleviates TGF-β1-induced increase in lens nuclear density. Collectively, these findings highlight the significance of m6A-modified PCP pathway in regulating postnatal lens fiber organization, which may hold great promise as a therapeutic target for HMC.

Proteomic signatures of retinal pigment epithelium-derived exosomes in myopic and non-myopic tree shrew eyes

Purpose

The retinal pigment epithelium (RPE) transmits growth signals from the neural retina to the choroid in the emmetropization pathway, but the underlying molecular mechanisms remain poorly understood. Here, we compared the proteomic profiles of RPE-derived exosomes between myopic and non-myopic eyes of tree shrews, dichromatic mammals closely related to primates.

Methods

Four myopic (159-210 days of visual experience, DVE) and seven non-myopic eyes (156-210 DVE) of tree shrews were included. Non-cycloplegic refractive error was measured with Nidek autorefractor, and axial ocular component dimensions were recorded with LenStar. Tissue was collected, yielding RPE-lined eyecups, which were subsequently incubated in L-15 culture media for 2 h. The RPE-derived exosomes were then enriched and purified from the incubation media by double ultracentrifugation and characterized by imaging and molecular methods. Exosomal proteins were identified and quantified with mass spectrometry, examined using GO and KEGG analyses, and compared between myopic and non-myopic samples.

Results

Out of 506 RPE exosomal proteins identified, 48 and 41 were unique to the myopic and non-myopic samples, respectively. There were 286 differentially expressed proteins in the myopic samples, including 79 upregulated and 70 downregulated. The top three upregulated proteins were Histone H4 (Fold Change, FC = 3.04, p = 0.09), PTB 1 (FC = 2.59, p = 0.08) and Histone H3.1 (FC = 2.59, p = 0.13), while the top three downregulated proteins were RPS5 (FC = -2.41, p=0.004), ACOT7 (FC=-2.15, p = 0.04) and CRYBB2 (FC = -2.14, p = 0.05). Other differentially expressed proteins included LUM, VCL, SEPTIN11, GPX3, SPTBN1, SEPTIN7, RPL10A, KCTD12, FGG, and FMOD. Proteomic analysis revealed a low abundance of ATP6V1B2 and crystallin beta B2, and a significant depletion of the crystallin protein family (crystallin A2, A3, and B3 subunits) in the myopic samples. The enrichment analyses showed extracellular matrix, cytoskeletal dynamic, and cell-matrix adhesion as the primary components associated with the RPE exosomal proteins in myopic eyes.

Conclusion

Using standard molecular and imaging techniques, this study provides the first demonstration of the ex-vivo RPE exosome biogenesis from tree shrew eyes. The results showed distinct differential expressions of the RPE exosomal proteins between the myopic and non-myopic eyes, with several proteins unique to each group. Future targeted proteomic studies of identified candidate exosomal protein signatures could elucidate the molecular mechanism of RPE exosome-mediated growth signal transmission in the emmetropization pathway.

Covariation of scleral remodeling and PI3K/Akt signaling pathway in experimental myopia

The present study aimed to investigate the role of the PI3K/Akt signaling pathway in scleral remodeling in the development of negative lens-induced myopia (LIM). The change of scleral morphology in experimental myopic guinea pigs was observed by transmission electron microscopy, Masson staining, and TUNEL assay, respectively. Meanwhile, the levels of the PI3K/AKT signaling pathway- and scleral remodeling-related molecules in scleral tissues were determined by real-time quantitative PCR (qPCR), enzyme-linked immunosorbent assay (ELISA), immunofluorescence, immunohistochemical staining, and western blot, respectively. We found that 2-week myopic induction can elevate PIK3R3 and AKT2 levels and activate the PI3K/Akt signaling pathway, enhance the expression of E-cadherin and matrix metallopeptidase 2 (MMP2), and decrease the level of transforming growth factor-beta 1 (TGF-β1), tissue inhibitor of matrix metalloproteinase-2 (TIMP2), and collagen (COLI) in the scleral tissue of myopic guinea pigs, thereby leading to scleral remolding. However, 4-week myopic induction could inhibit the PI3K/AKT signaling pathway and induce apoptosis, accompanied by increased MMP2, E-cadherin, and decreased TGF-β1, TIMP2, and COLI. Results reveal that the disturbed PI3K/AKT signaling plays a role in scleral remodeling in the experimental myopia through orchestrating apoptosis.

In Vivo Brillouin Analysis of Lens Nucleus and Cortex in Adult Myopic Eyes and Their Correlation With Accommodation

Purpose

The purpose of this study was to investigate the in vivo biomechanical properties of crystalline lens nucleus and cortex in adults with myopia, their potential influences, and the correlation between these properties and ocular accommodation.

Methods

The study included 195 right eyes of 195 participants, divided into 4 groups based on spherical equivalent: emmetropia (37 eyes), low myopia (41 eyes), moderate myopia (59 eyes), and high myopia (58 eyes). Participants underwent comprehensive ophthalmological examinations, including intraocular pressure, axial length, cycloplegic refraction, lens morphology, accommodation measurements, and Brillouin optical scanning of the lens. Additionally, demographic information, such as age and sex, was recorded. Normality tests were performed on the data using the Kolmogorov-Smirnov test. Between-group differences were examined using the Kruskal-Wallis test. Correlation and multiple regression analyses were conducted to analyze the factors associated with lens biomechanical properties and accommodation.

Results

The mean longitudinal modulus of the crystalline lens nucleus (LMN), anterior cortex (LMAC), and posterior cortex (LMPC) was 3.395 ± 0.027 GPa, 3.030 ± 0.066 GPa, and 2.990 ± 0.066 GPa, respectively, in adult myopia and 3.342 ± 0.024 GPa, 3.015 ± 0.0488 GPa, and 2.978 ± 0.049 GPa, respectively, in emmetropia. LMN was significantly higher in myopia (difference = 0.047, 95% confidence interval [CI] = 0.037 to 0.057, P < 0.001) and increased significantly with higher degrees of myopia (standardized β = -0.712, P < 0.001). No statistical differences in the LMAC or LMPC were observed between myopia and emmetropia. Lens densitometry on the centerline was the only lens parameter independently correlated with LMN (standardized β = -0.282, P < 0.01). Increased LMN in myopia was independently correlated with increased amplitude of accommodation (AMP) and decreased accommodative facility (AF; standardized β = 0.198, -0.237, all P < 0.05).

Conclusions

LMN was significantly higher in adult patients with myopia than in emmetropia and increased with increasing myopia. Increased LMN in myopia significantly correlated with decreased AF and increased AMP. High LMN may be an important biological alteration during the development of adult myopia, especially high myopia, providing new insights into myopia pathogenesis.

Identifying pathological myopia associated genes with GenePlexus in protein-protein interaction network

Introduction

Pathological myopia, a severe form of myopia, is characterized by an extreme elongation of the eyeball, leading to various vision-threatening complications. It is broadly classified into two primary types: high myopia, which primarily involves an excessive axial length of the eye with potential for reversible vision loss, and degenerative myopia, associated with progressive and irreversible retinal damage.

Methods

Leveraging data from DisGeNET, reporting 184 genes linked to high myopia and 39 genes associated with degenerative myopia, we employed the GenePlexus methodology in conjunction with screening tests to further explore the genetic landscape of pathological myopia.

Results and discussion

Our comprehensive analysis resulted in the discovery of 21 new genes associated with degenerative myopia and 133 genes linked to high myopia with significant confidence. Among these findings, genes such as ADCY4, a regulator of the cAMP pathway, were functionally linked to high myopia, while THBS1, involved in collagen degradation, was closely associated with the pathophysiology of degenerative myopia. These previously unreported genes play crucial roles in the underlying mechanisms of pathological myopia, thereby emphasizing the complexity and multifactorial nature of this condition. The importance of our study resides in the uncovering of new genetic associations with pathological myopia, the provision of potential biomarkers for early screening, and the identification of therapeutic targets.

Understanding cataract development in axial myopia: The contribution of oxidative stress and related pathways

Myopia is an evolving global health challenge, with estimates suggesting that by 2050 it will affect half of the world's population, becoming the leading cause of irreversible vision loss. Moreover, myopia can lead to various complications, including the earlier onset of cataracts. Given the progressive aging of the population and the increase in life expectancy, this will contribute to a rising demand for cataract surgery, posing an additional challenge for healthcare systems. The pathogenesis of nuclear and posterior subcapsular cataract (PSC) development in axial myopia is complex and primarily involves intensified liquefaction of the vitreous body, excessive production of reactive oxygen species, impaired antioxidant defense, and chronic inflammation in the eyeball. These factors contribute to disruptions in mitochondrial homeostasis, abnormal cell signaling, lipid peroxidation, protein and nucleic acid damage, as well as the induction of adverse epigenetic modifications. Age-related and oxidative processes can cause destabilization of crystallins with subsequent protein accumulation, which finally drives to a lens opacification. Moreover, an altered redox status is one of the major contributors to the pathogenesis of PSC. This review aims to summarize the mechanisms known to be responsible for the accelerated development of cataracts in axial myopia and to enhance understanding of these relationships.

Enhanced ferroptosis sensitivity promotes the formation of highly myopic cataract via the DDR2-Hippo pathway

Highly myopic cataract (HMC) is a leading cause of blindness among the working-age individuals, with its pathogenesis poorly understood. This study aimed to elucidate the role of ferroptosis in HMC development as well as the underlying mechanisms. In HMC lens epithelia, levels of Fe2+ and lipid peroxidation were found elevated, with increased vulnerability towards ferroptosis as revealed by transmission electron microscopy. Mechanistically, RNA sequencing of HMC lens epithelial samples identified up-regulated expression of discoidin domain receptor tyrosine kinase 2 (DDR2) as a key factor, which could enhance ferroptosis sensitivity via the Src-Hippo pathway. Specifically, DDR2 interacted with Src kinase, leading to the nuclear translocation of homologous transcriptional regulators (yes-associated protein 1 [YAP1] and WW domain containing transcription regulator 1 [WWTR1]) of the Hippo pathway, which altered the expression level of ferroptosis-related genes. Notably, highly myopic eyes of mice exhibited higher sensitivity to RSL3, a ferroptosis inducer, manifested as more severe nuclear lens opacities both in vitro and in vivo compared with the contralateral control eyes, which could be alleviated by inhibitors of either ferroptosis or DDR2. Altogether, these findings highlighted the role of DDR2 in mediating ferroptosis in HMC formation, providing a novel insight for therapeutic interventions.

Comprehensive bioinformatics analysis of metabolism‑related microRNAs in high myopia in young and old adults with age‑related cataracts

High myopia and age‑related cataracts are prevalent ocular disorders that compromise visual acuity. The molecular mechanisms underlying these conditions remain largely unclear. Here, microRNA (miRNA or miR) sequencing was performed on aqueous humor samples obtained from individuals with age‑related cataracts and high myopia (AH, n=9), young patients with high myopia (YH, n=9) and a control group of elderly patients with age‑related cataracts, matched in terms of sex and age (AN, n=9). miRNA sequencing and differential expression were performed. Intersecting miRNAs were identified, as well as metabolism‑related genes from MsigDB were intersected with miRNA target genes. Functional enrichment was performed and disease targets predicted using DisGeNET. A protein‑protein interaction network was built with STRING, and hub genes were identified via Cytoscape. GeneMANIA analyzed hub genes, while drug predictions were made using Comparative Toxicogenomics Database. Long non‑coding RNAs and transcription factors were predicted via mirNet and ChEA3. Results were validated by RT‑qPCR. A total of 18 miRNAs were significantly differential expressed between AH and AN group, of which eight were up‑ and 10 were downregulated. A total of 23 miRNAs were significantly differential expressed between the YH and AN group, of which six were up‑ and 17 were downregulated. hsa‑miR‑490‑3p, hsa‑miR‑4423‑3p and hsa‑miR‑4485‑3p may serve as characteristic miRNAs. A total of 289 target genes were predicted. Functional enrichment analysis yielded 169 terms, with 'herpes simplex virus 1 infection' the most significantly enriched. There were 19 metabolism‑associated target genes linked with these miRNAs, suggesting a potential role of metabolic processes in pathogenesis of these conditions. The biosynthetic process of carbohydrate derivatives may serve a key role during the development of high myopia. There were 10 hub genes and Propionyl‑CoA Carboxylase Subunit β could potentially serve as a biomarker. Drugs that could modulate their function were predicted; cyclosporine, tretinoin and acetaminophen may exert a broad influence on these hub genes. Hub gene networks based on the miRNAs were constructed to predict 44 associated long non‑coding RNAs and 98 transcription factors. The present findings offer novel insights into the molecular mechanisms of age‑related cataracts and high myopia and propose potential therapeutic targets.

Understanding how the immune system environment is controlled in high myopia cases

High myopia (HM) is characterized by a significant extension of the eye axis; it has emerged as a serious global public health issue recently. In addition to causing severe visual impairment, HM is associated with several problems that may compromise an individual's vision. Although genetic and environmental factors in HM have been extensively investigated, increasing evidence implicates the immune system and its microenvironment in its pathogenesis. In this review, we explore the complex interactions between cytokines, immune cells, and the eye environment to elucidate the complex processes controlling the immune response in HM. Furthermore, we investigated treatments modulating the immune response and alleviating the progression of HM and its complications. Through a review of the current relevant studies, we highlight the critical functions of the immune system in the multifactorial development of HM. With the evolving understanding of the immune system's involvement in HM, this review provides a valuable resource to clinicians and researchers to develop targeted interventions and personalized treatments for individuals with this vision-threatening condition.

Spatial and morphologic features of lenses with different axial lengths in cataract patients: a swept-source optical coherence tomography-based study

BACKGROUND

To investigate the spatial and morphologic features of lenses with different axial length (ALs) in cataract patients using swept-source optical coherence tomography (SS-OCT).

METHODS

Totally 105 eyes of 105 patients scheduled to have cataract surgery were included. Eyes were divided into the control (AL < 24.5 mm), moderate myopia (MM, 24.5 ≤ AL < 26 mm) and high myopia (HM, AL ≥ 26 mm) groups. Spatial features including lens vault (LV) and iris-to-lens distance (ILD), and morphologic features including radii of curvature of anterior and posterior surface (Ra, Rp), lens diameter (LD) and lens thickness (LT) were measured in eight directions by SS-OCT.

RESULTS

Spatially, the HM group had larger LV and ILD than the control group (both P < .05). LV and ILD were negatively correlated with AL, respectively (LV: r = -.484, P < .0001; ILD: r = -.656, P < .0001). Morphologically, both MM and HM groups had greater Ra and Rp than the control group. Ra was positively correlated with AL (r = .622, P < .0001), while the relationship between Rp and AL was non-linear. Moreover, the MM and HM groups had larger LD than the control group (both P < .001). Anterior LT was thinner in the HM than in the MM group (P = .026), while posterior LT between these two groups was similar. When compared in eight directions, similar trends were seen in Ra, Rp and LD, and the HM group showed a greater difference in Ra between horizontal and vertical directions.

CONCLUSIONS

This SS-OCT-based study showed that longer axial length is associated with a flatter lens, which was mainly attributed to the increase of Ra and LD. Longitudinal studies would be necessary to establish a causal relationship and temporal progression.

Morphologic features of iris in highly myopic eyes based on a novel swept-source optical coherence tomography

BACKGROUND

To investigate the morphologic features of iris in the highly myopic (HM) eyes using a novel swept-source optical coherence tomography (SS-OCT).

METHODS

In this retrospective case-control study, 100 eyes of 100 patients scheduled to have cataract surgery were included, categorized into the control (22 mm< AL < 24.5 mm) and HM (AL ≥ 26 mm) groups. Iris volume (IV), area of anterior iris surface (IS), area of posterior IS, and average iris thickness (IT), as well as anterior chamber volume (ACV) and trabecular-iris space at 500 µm (TISA 500) were evaluated using SS-OCT. The associated factors with morphologic features of iris were also investigated.

RESULTS

The HM group showed significantly larger IV and area of anterior and posterior IS than the control group (all P < 0.001), while no difference was identified in IT between the groups. Similar trend in IV was seen in the superior and nasal segments, and area of anterior and posterior IS showed similar trends in all segments except the temporal segment. The IV, area of anterior and posterior IS were all positively correlated with AL (all P < 0.001). Multivariate linear regression revealed that a larger IV was associated with greater ACV. Both larger areas of anterior IS and posterior IS were associated with male, longer AL, greater ACV, and smaller TISA 500.

CONCLUSIONS

The HM eyes showed larger IV and area of IS than the control eyes, indicating a coronal expansion of the iris with AL. Iris morphology correlated with anterior chamber angle configuration.

Animal modeling for myopia

Background

Myopia is one of the most common eye diseases globally, and has become an increasingly serious health concern among adolescents. Understanding the factors contributing to the onset of myopia and the strategies to slow its progression is critical to reducing its prevalence.

Main text

Animal models are key to understanding of the etiology of human diseases. Various experimental animal models have been developed to mimic human myopia, including chickens, rhesus monkeys, marmosets, mice, tree shrews, guinea pigs and zebrafish. Studies using these animal models have provided evidences and perspectives on the regulation of eye growth and refractive development. This review summarizes the characteristics of these models, the induction methods, common indicators of myopia in animal models, and recent findings on the pathogenic mechanism of myopia.

Conclusions

Investigations using experimental animal models have provided valuable information and insights into the pathogenic mechanisms of human myopia and its treatment strategies.

Nonlinear pathological trajectory of a high-myopia C57/BL6J mouse model induced by form deprivation

Introduction

To establish a high myopia model in C57BL/6J mice with monocular form deprivation myopia (FDM) and investigate its ocular structure pathological trajectory.

Methods

Healthy 3-week-old C57BL/6J mice were divided into an FDM group (n = 36) and a control group (n = 24). The left eyes of the FDM group were patched, while the right eyes served as controls. Biometric parameters and fundus morphology were assessed at baseline and after 4, 8, and 12 weeks of form deprivation.

Results

Significant differences were observed in the deprived eyes, including longer axial length, higher refractive power, deeper vitreous chambers, thinner retina, choroid, and sclera, and smaller scleral fibers' diameters under a transmission electron microscope. Retinal vascular area proportion in covered eyes decreased significantly (P < 0.05), with a decline rate of 11% from weeks 4 to 8 and a faster decline of 19% from weeks 8 to 12, while this proportion increased significantly in control eyes.

Discussion

This study successfully induced a high myopia model in mice with long-term form deprivation. The axial length grew dramatically in FDM in the first 8 weeks, while the pathological progress of the fundus accelerated from weeks 8 to 12.

Insights into Myopia from Mouse Models

Animal models are critical for understanding the initiation and progression of myopia, a refractive condition that causes blurred distance vision. The prevalence of myopia is rapidly increasing worldwide, and myopia increases the risk of developing potentially blinding diseases. Current pharmacological, optical, and environmental interventions attenuate myopia progression in children, but it is still unclear how this occurs or how these interventions can be improved to increase their protective effects. To optimize myopia interventions, directed mechanistic studies are needed. The mouse model is well-suited to these studies because of its well-characterized visual system and the genetic experimental tools available, which can be combined with pharmacological and environmental manipulations for powerful investigations of causation. This review describes aspects of the mouse visual system that support its use as a myopia model and presents genetic, pharmacological, and environmental studies that significantly contribute to our understanding of the mechanisms that underlie myopigenesis.

Gut microbiota-derived indole-3-acetic acid suppresses high myopia progression by promoting type I collagen synthesis

High myopia (HM) is a leading cause of blindness worldwide with currently no effective interventions available. A major hurdle lies in its often isolated perception as a purely ocular morbidity, disregarding potential systemic implications. Recent evidence suggests the existence of a gut-eye axis; however, the role of gut microbiota in the pathogenesis of HM remains largely unexplored. Herein, we provide a potential crosstalk among HM's gut dysbiosis, microbial metabolites, and scleral remodeling. Utilizing 16S rRNA gene sequencing, we observed an altered gut microbiota profile in HM patients with a significant reduction in probiotic abundance compared with healthy controls. Subsequent targeted metabolic profiling revealed a notable decrease in plasma levels of the gut microbiota-derived metabolite indole-3-acetic acid (3-IAA) among HM patients, which is closely associated with the reduced probiotics, both negatively correlated with HM severity. Genetic analyses determined that gut microbiota are causally associated with myopia risk. Importantly, when mice subjected to HM modeling receive fecal microbiota transplantation from healthy donors, there is an increase in 3-IAA plasma levels and simultaneous retardation of HM progression along with better maintenance of collagen type I alpha 1 (COL1A1) expression in the sclera. Furthermore, 3-IAA gavage achieves similar effects. Mechanistic investigations confirm the transcriptional activation of COL1A1 by 3-IAA via promoting the enrichment of SP1 to its promoter. Together, our findings provide novel insights into the gut microbiota-eye axis in the pathogenesis of HM and propose new strategies for HM intervention by remodeling the gut microbiota and indole supplementation.

Complications of high myopia: An update from clinical manifestations to underlying mechanisms

Background

High myopia is one of the major causes of visual impairment and has an ever-increasing prevalence, especially in East Asia. It is characterized by excessive axial elongation, leading to various blinding complications that extend beyond mere refractive errors and persist immovably after refractive surgery, presenting substantial public health challenge.

Main text

High myopia-related complications include lens pathologies, atrophic and tractional maculopathy, choroidal neovascularization, peripheral retinal degenerations and retinal detachment, and glaucoma and heightened susceptibility to intraocular pressure (IOP) elevation. Pathological lens changes characteristic of high myopia include early cataractogenesis, overgrowth of lens, weakened zonules, and postoperative capsular contraction syndrome, possibly driven by inflammatory pathogenesis, etc. Dome-shaped macula and cilioretinal arteries are two newly identified protective factors for central vision of highly myopic patients. These patients also face risks of open-angle glaucoma and IOP spike following intraocular surgery. Morphologic alternations of optic nerve in high myopia can complicate early glaucoma detection, necessitating comprehensive examinations and close follow-up. Anatomically, thinner trabecular meshwork increases this risk; conversely lamina cribrosa defects may offer a fluid outlet, potentially mitigating the pressure. Notably, anxiety has emerged as the first recognized extra-ocular complication in high myopia, with an underlying inflammatory pathogenesis that connects visual stimulus, blood and brain.

Conclusions

High myopia induces multiple ocular and potential mental health complications, underscoring the need to develop more effective strategies to improve both physical and emotional well-being of these patients, among which anti-inflammation might possibly represent a promising new target.

Changes in Subfoveal Choroidal Thickness after Orthokeratology in Myopic Children: A Systematic Review and Meta-Analysis

AIMS

This study aimed to synthesize the variations in subfoveal choroidal thickness (SFCT) observed at different follow-up intervals in myopic children undergoing orthokeratology treatment.

MATERIALS AND METHODS

Relevant articles were systematically retrieved from databases such as PubMed, EMBASE, Web of Science, and Cochrane Library. The retrieval period extended from the inception of these databases to November 2023. Means and standard deviations (SD) of baseline and post-treatment SFCT were selected as the results for analysis and calculation.

RESULTS

A total of eight articles involving 478 eyes fulfilled the inclusion criteria. At 1 month, 3 months, and 6 months intervals, the SFCT demonstrated significant increases by 16.74 μm (95% CI: 8.66, 24.82; p < 0.0001), 13.41 μm (95% CI: 4.36, 22.45; p = 0.004), and 17.57 μm (95% CI: 8.41, 26.73; p = 0.0002), respectively. Besides, children treated with orthokeratology exhibited a notably thicker change of SFCT in comparison with children with single-vision spectacles (SVL) (WMD = 13.50, 95% CI: 11.69, 15.13; p < 0.0001).

CONCLUSION

Myopic children undergoing orthokeratology treatment experience a discernible increase in SFCT at 1 month, 3 months, and 6 months. Furthermore, compared to children utilizing SVL, those undergoing orthokeratology manifest a more pronounced thickening of SFCT.

Circulating Autoantibody Profiling Identifies LIMS1 as a Potential Target for Pathogenic Autoimmunity in pathologic Myopia

High myopia is a leading cause of blindness worldwide, among which pathologic myopia, characterized by typical myopic macular degeneration, is the most detrimental. However, its pathogenesis remains largely unknown. Here, using a HuProt array, we first initiated a serological autoantibody profiling of high myopia and identified 18 potential autoantibodies, of which anti-LIMS1 autoantibody was validated by a customized focused microarray. Further subgroup analysis revealed its actual relevance to pathologic myopia, rather than simple high myopia without myopic macular degeneration. Mechanistically, anti-LIMS1 autoantibody predominantly belonged to IgG1/IgG2/IgG3 subclasses. Serum IgG obtained from patients with pathologic myopia could disrupt the barrier function of retinal pigment epithelial cells via cytoskeleton disorganization and tight junction component reduction, and also trigger a pro-inflammatory mediator cascade in retinal pigment epithelial cells, which were all attenuated by depletion of anti-LIMS1 autoantibody. Together, these data uncover a previously unrecognized autoimmune etiology of myopic macular degeneration in pathologic myopia.

Aggravated visual toxicity in zebrafish larvae upon co-exposure to titanium dioxide nanoparticles and bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate

The bioavailability and toxicity of organic pollutants in aquatic organisms can be largely affected by the co-existed nanoparticles. However, the impacts of such combined exposure on the visual system remain largely unknown. Here, we systematically investigated the visual toxicity in zebrafish larvae after single or joint exposure to titanium dioxide nanoparticles (n-TiO2) and bis(2-ethylhexyl)-2,3,4,5-tetrabromophthalate (TBPH) at environmentally relevant levels. Molecular dynamics simulations revealed the enhanced transmembrane capability of the complex than the individual, which accounted for the increased bioavailability of both TBPH and n-TiO2 when combined exposure to zebrafish. Transcriptome analysis showed that co-exposure to n-TiO2 and TBPH interfered with molecular pathways related to eye lens structure and sensory perception of zebrafish. Particularly, n-TiO2 or TBPH significantly suppressed the expression of βB1-crystallin and rhodopsin in zebrafish retina and lens, which was further enhanced after co-exposure. Moreover, we detected disorganized retinal histology, stunted lens development and significant visual behavioral changes of zebrafish under co-exposure condition. The overall results suggest that combined exposure to water borne n-TiO2 and TBPH increased their bioavailability, resulted in severer damage to optic nerve development and ultimately abnormal visual behavior patterns, highlighting the higher potential health risks of co-exposure to aquatic vertebrates.

Analysis and validation of potential ICD-related biomarkers in development of myopia using machine learning

PURPOSE

We aimed to identify and verify potential biomarkers in the development of myopia associated with immunogenic cell death (ICD).

METHODS

We download high myopia (HM) dataset GSE136701 from Gene Expression Omnibus. Differentially expressed genes in HM were identified to overlapped with ICD-related genes. Least absolute shrinkage and selection operator were used to select the Hub genes. Furthermore, the correlation between the hub genes and immune infiltration, immune response activities, and hub genes Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways analysis was investigated using Spearman's rank correlation. Prediction of the miRNAs upstream of the Hub genes was based on the TargetScan database. We used guinea pig lens-induced myopia model's scleral tissues performed quantitative real-time polymerase chain reaction.

RESULTS

We identified overlapped with ICD-related genes (LY96, IL1A, IL33, and AGER) and two genes (LY96 and AGER) as hub genes. Single sample gene set enrichment analysis and Spearman's rank correlation revealed that hub gene expression levels in HM were significantly correlated with the infiltration percentages of CD56dim natural killer cells, macrophages, immature B cells, and the immune response activities of APC co-stimulation and Kyoto Encyclopedia of Genes and Genomes pathways, such as terpenoid backbone biosynthesis, aminoacyl-trna biosynthesis, Huntington's disease, oxidative phosphorylation; there were a few additional signaling pathways compared to normal samples. Additionally, several miRNA were predicted as upstream regulators of LY96 and AGER. LY96 was identified as a significantly differentially expressed biomarker in myopia guinea pig's scleral tissues, as verified by qPCR.

CONCLUSION

LY96 was identified and verified as a ICD-related potential myopia biomarker. Molecular mechanisms or pathways involved in myopia development by LY96 requires further research.

Effects on radius of curvature and refractive power of the cornea and crystalline lens by atropine 0.01% eye drops

PURPOSE

The morphological changes in the cornea and crystalline lens have not been closely evaluated after the administration of atropine 0.01%. This study aims to evaluate the radii of curvature and refractive power of the cornea and lens in myopic eyes during atropine 0.01% treatment.

METHODS

Children aged 6-14 years with myopia <-6.0 D were randomized to receive atropine 0.01% once nightly with single vision lenses or simply wear single vision lenses. Ocular biometric parameters were measured using the IOLMaster 700 biometry and the radii of corneal and lenticular curvature were simulated using a customized program.

RESULTS

At the 9-month visit, 69 atropine-treated eyes and 50 control eyes were included in the final analyses. In atropine-treated eyes, the posterior corneal surface steepened (-0.05 ± 0.13 mm) and the anterior lenticular surface flattened (0.20 ± 0.69 mm) significantly within 3-6 months, whereas the posterior corneal surface and anterior lenticular surface gradually flattened (0.07 ± 0.23 and 0.32 ± 0.80 mm respectively) in the control eyes over 9 months. The difference in the change of corneal refractive power was significant between groups (-0.03 ± 0.18 D vs. 0.11 ± 0.24 D, p = 0.001), while that in the change of lenticular refractive power was statistically insignificant (0.01 ± 0.92 D vs. -0.22 ± 0.86 D, p = 0.161).

CONCLUSIONS

The administration of atropine 0.01% exhibited a clinically short and subtle impact on the cornea and lens, which may shed light on new targets of action for atropine in inhibiting myopia.

A framework for Frizzled-G protein coupling and implications to the PCP signaling pathways

The ten Frizzled receptors (FZDs) are essential in Wnt signaling and play important roles in embryonic development and tumorigenesis. Among these, FZD6 is closely associated with lens development. Understanding FZD activation mechanism is key to unlock these emerging targets. Here we present the cryo-EM structures of FZD6 and FZD3 which are known to relay non-canonical planar cell polarity (PCP) signaling pathways as well as FZD1 in their G protein-coupled states and in the apo inactive states, respectively. Comparison of the three inactive/active pairs unveiled a shared activation framework among all ten FZDs. Mutagenesis along with imaging and functional analysis on the human lens epithelial tissues suggested potential crosstalk between the G-protein coupling of FZD6 and the PCP signaling pathways. Together, this study provides an integrated understanding of FZD structure and function, and lays the foundation for developing therapeutic modulators to activate or inhibit FZD signaling for a range of disorders including cancers and cataracts.

FOXM1 Participates in Scleral Remodeling in Myopia by Upregulating APOA1 Expression Through METTL3/YTHDF2

Purpose

Apolipoprotein A1 (APOA1) is a potential crucial protein and treatment goal for pathological myopia in humans. This study set out to discover the function of APOA1 in scleral remodeling in myopia and its underlying mechanisms.

Methods

A myopic cell model was induced using hypoxia. Following loss- and gain-of function experiments, the expression of the myofibroblast transdifferentiation-related and collagen production-related factors Forkhead box M1 (FOXM1), APOA1, and methyltransferase-like 3 (METTL3) in the myopic cell model was examined by quantitative reverse transcription polymerase chain reaction (RT-qPCR) and western blotting. The proliferation and apoptosis were determined by Cell Counting Kit-8 assay and flow cytometry, respectively. Chromatin immunoprecipitation (ChIP) was employed to examine FOXM1 enrichment in the METTL3 promoter, methylated RNA immunoprecipitation (Me-RIP) to examine the N6-methyladenosine (m6A) modification level of APOA1, and photoactivatable ribonucleoside-enhanced crosslinking and immunoprecipitation (PAR-CLIP) to examine the binding between METTL3 and APOA1.

Results

Hypoxia-induced human scleral fibroblasts (HSFs) had high APOA1 and FOXM1 expression and low METTL3 expression. FOXM1 knockdown elevated METTL3 expression and downregulated APOA1 expression. FOXM1 was enriched in METTL3 promoter. APOA1 or FOXM1 knockdown or METTL3 overexpression reversed the hypoxia-induced elevation in vinculin, paxillin, and α-smooth muscle actin (α-SMA) levels and apoptosis and the reduction in collagen, type I, alpha 1 (COL1A1) level and cell proliferation in HSFs. METTL3 or YTH N6-methyladenosine RNA binding protein F2 (YTHDF2) knockdown or APOA1 overexpression reversed the impacts of FOXM1 knockdown on vinculin, paxillin, α-SMA, and COL1A1 expression and cell proliferation and apoptosis.

Conclusions

FOXM1 elevated the m6A methylation level of APOA1 by repressing METTL3 transcription and enhanced APOA1 mRNA stability and transcription by reducing the YTHDF2-recognized m6A methylated transcripts.

Gut microbiome and plasma metabolome alterations in myopic mice

Background

Myopia is one of the most common eye diseases leading to blurred distance vision. Inflammatory diseases could trigger or exacerbate myopic changes. Although gut microbiota bacteria are associated with various inflammatory diseases, little is known about its role in myopia.

Materials and methods

The mice were randomly divided into control and model groups, with the model group being attached-30D lens onto the eyes for 3 weeks. Then, mouse cecal contents and plasma were collected to analyze their intestinal microbiota and plasma metabolome.

Results

We identified that the microbial composition differed considerably between the myopic and non-myopic mice, with the relative abundance of Firmicutes phylum decreased obviously while that of Actinobacteria phylum was increased in myopia. Furthermore, Actinobacteria and Bifidobacterium were positively correlated with axial lengths (ALs) of eyeballs while negatively correlated with refractive diopters. Untargeted metabolomic analysis identified 141 differentially expressed metabolites, and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis revealed considerable enrichment mainly in amino acid metabolism pathways. Notably, pathways involved glutamate metabolism including "Glutamine and D-glutamate metabolism" and "Alanine, aspartate and glutamate metabolism" was changed dramatically, which presented as the concentrations of L-Glutamate and L-Glutamine decreased obviously in myopia. Interestingly, microbiome dysbiosis and metabolites alternations in myopia have a disrupting gut barrier feature. We further demonstrated that the gut barrier function was impaired in myopic mice manifesting in decreased expression of Occludin, ZO-1 and increased permeation of FITC-dextran.

Discussion

Myopic mice had obviously altered gut microbiome and metabolites profiles compared to non-myopic mice. The dysbiosis and plasma metabolomics shift in myopia had an interrupting gut barrier feature. Our study provides new insights into the possible role of the gut microbiota in myopia and reinforces the potential feasibility of microbiome-based therapies in myopia.

Actual lens positions of three intraocular lenses in highly myopic eyes: an ultrasound biomicroscopy-based study

AIM

To evaluate the actual lens positions (ALPs) of three intraocular lenses (IOLs) in highly myopic eyes and to identify relevant factors using ultrasound biomicroscopy (UBM).

METHODS

Ninety-three highly myopic eyes (93 patients) that underwent uneventful cataract surgery were included: 36 eyes were implanted with Zeiss 409MP IOLs, 27 with Rayner 920H IOLs and 30 with HumanOptics MCX11 IOLs. The prediction error (PE), ALP determined by UBM and the factors associated with ALP at 3 months after surgery were evaluated.

RESULTS

The eyes in the MCX11 IOL group had a more hyperopic PE (0.67±0.45 diopters (D)) and greater ALP (4.86±0.39 mm) than those in the 409MP and 920H IOL groups at 3 months after surgery (PE: -0.25±0.54 and -0.16±0.65 D, respectively; ALP: 4.34±0.26 and 4.14±0.32 mm, respectively). The MCX11 IOLs showed more backward bending deformation after surgery than 409MP and 920H IOLs. The radius of curvature of the IOL was negatively correlated with ALP (r=-0.532, p=0.002) in the MCX11 IOL group, but not in the other two groups. Multivariate analysis showed that MCX11 IOLs were more prone to bending in highly myopic eyes with a smaller anterior capsular opening (β=0.236, p=0.023) and lower implanted power (β=0.542, p=0.001).

CONCLUSION

In highly myopic eyes, IOLs with good capsular support show less backward bending, which result in a more stable lens position and refractive status postoperatively. Severe capsular contraction and low implanted power are risk factors for bending of certain IOLs.

Effects of inflammation on myopia: evidence and potential mechanisms

As the most common type of refractive error, myopia has become one of the leading causes of visual impairment. With the increasing prevalence of myopia, there is a growing need to better understand the factors involved in its development. Inflammation, one of the most fundamental pathophysiological processes in humans, is a rapid response triggered by harmful stimuli and conditions. Although controlled inflammatory responses are necessary, over-activated inflammation is the common soil for many diseases. The impact of inflammation on myopia has received rising attention in recent years. Elevated inflammation may contribute to myopia progression either directly or indirectly by inducing scleral remodeling, and myopia development may also increase ocular inflammation. This article provides a comprehensive review of the interplay between inflammation and myopia and the potential biological mechanisms, which may present new targets for understanding the pathology of myopia and developing myopia therapies.

Tear inflammatory cytokines as potential biomarkers for myopic macular degeneration

Previous studies have reported that inflammatory cytokine levels increase in the intraocular fluids (aqueous humor and vitreous) of highly myopic eyes, However, there has been currently no study revealing the levels of inflammatory cytokines in tear. Therefore, this study aimed to determine tear cytokine levels of highly myopic eyes, and their relationships with myopic macular degeneration (MMD). This case-control study screened inflammatory cytokines of tear samples from 132 highly myopic and 105 emmetropic eyes using a multiplex cytokine antibody array, and cytokines showing significant intergroup differences were further validated using ProQuantum immunoassays in tear samples from another 60 highly myopic and 60 emmetropic eyes. Ultra-widefield fundus photographs of eyes were classified according to the meta-analyses of the Pathologic Myopia Classification. Associations between tear cytokine levels and MMD category were investigated. As a result, tear levels of interleukin (IL)-6, IL-13 and monocyte chemoattractant protein (MCP)-1 were screened significantly higher in highly myopic eyes than in emmetropic controls (IL-6: 11.70 ± 16.81 versus 8.22 ± 10.76 pg/mL; MCP-1: 63.60 ± 54.40 versus 33.87 ± 43.82 pg/mL; both P < 0.05). Validation assays further demonstrated the elevated concentrations of IL-6 and MCP-1 (IL-6: 13.97 ± 8.41 versus 8.06 ± 7.94 pg/mL, P < 0.001; MCP-1: 32.69 ± 8.41 versus 18.07 ± 8.41 pg/mL, P = 0.003). Tear levels of IL-6 and MCP-1 differed significantly among MMD categories (both P < 0.05). The area under receiver operating characteristic curve were 0.783 and 0.682 respectively (both P < 0.05), when using tear IL-6 and MCP-1 levels to predict the presence of MMD (category ≥2). The ordered logistic regression model also indicated that longer axial length, and higher IL-6 and MCP-1 tear levels were independent predictors of higher MMD category. In our study, highly myopic eyes presented significantly higher levels of tear IL-6 and MCP-1, which may also serve as potential biomarkers for MMD.

Mechanism of Chinese botanical drug Dizhi pill for myopia: An integrated study based on bioinformatics and network analysis

To identify the active constituents, core targets, immunomodulatory functions and potential mechanisms of Dizhi pill (DZP) in the treatment of myopia. The active constituents and drug targets of DZP were searched in the TCMSP, Herb databases and correlational studies. The targets of myopia were searched in the TTD, Genecards, OMIM and Drugbank databases. Gene expression profile data of GSE136701 were downloaded from the GEO database and subjected to WGCNA and DEG analysis to screen for significant modules and targets of myopia. Intersectional targets of myopia and DZP and core targets of myopia were analyzed through the String database. The GO and KEGG enrichment analyses of the interested targets were conducted. Cibersort algorithm was used for immune infiltration analysis to investigate the immunomodulatory functions of DZP on myopia. Autodock was used to dock the important targets and active constituents. Eight targets (STAT3, PIK3CA, PIK3R1, MAPK1, MAPK3, HSP90AA1, MIP, and LGSN) and 5 active constituents (Quercetin, Beta-sitosterol, Diincarvilone A, Ferulic acid methyl ester, and Naringenin) were identified from DZP. In pathways identified by the GO and KEGG enrichment analyses, "ATP metabolic process" and "AGE-RAGE diabetes complication signaling" pathways were closely related to the mechanisms of DZP in the treatment of myopia. Molecular docking showed that both the intersectional targets and core targets of myopia could bind stably and spontaneously with the active constituents of DZP. This study suggested that the mechanisms of DZP in the treatment of myopia were related to active constituents: Quercetin, Beta-sitosterol, Diincarvilone A, Ferulic acid methyl ester and Naringenin, intersectional targets: STAT3, PIK3CA, PIK3R1, MAPK1, MAPK3, and HSP90AA1, core targets of myopia: MIP and LGSN, AGE-RAGE signaling pathway, positive regulation of ATP metabolic process pathway and immunomodulatory functions.

Challenges of refractive cataract surgery in the era of myopia epidemic: a mini-review

Myopia is the leading cause of visual impairment in the world. With ever-increasing prevalence in these years, it creates an alarming global epidemic. In addition to the difficulty in seeing distant objects, myopia also increases the risk of cataract and advances its onset, greatly affecting the productivity of myopes of working age. Cataract management in myopic eyes, especially highly myopic eyes is originally more complicated than that in normal eyes, whereas the growing population of cataract with myopia, increasing popularity of corneal and lens based refractive surgery, and rising demand for spectacle independence after cataract surgery all further pose unprecedented challenges to ophthalmologists. Previous history of corneal refractive surgery and existence of implantable collamer lens will both affect the accuracy of biometry including measurement of corneal curvature and axial length before cataract surgery, which may result in larger intraocular lens (IOL) power prediction errors and a compromise in the surgical outcome especially in a refractive cataract surgery. A prudent choice of formula for cataract patients with different characteristics is essential in improving this condition. Besides, the characteristics of myopic eyes might affect the long-term stability of IOL, which is important for the maintenance of visual outcomes especially after the implantation of premium IOLs, thus a proper selection of IOL accordingly is crucial. In this mini-review, we provide an overview of the impact of myopia epidemic on treatment for cataract and to discuss new challenges that surgeons may encounter in the foreseeable future when planning refractive cataract surgery for myopic patients.

CCL2-mediated inflammatory pathogenesis underlies high myopia-related anxiety

High myopia is a leading cause of blindness worldwide. It may lead to emotional defects that rely closely on the link between visual sensation and the central nervous system. However, the extent of the defects and its underlying mechanism remain unknown. Here, we report that highly myopic patients exhibit greater anxiety, accompanied by higher CC chemokine ligand 2 (CCL2) and monocyte levels in the blood. Similar findings are found in the mouse model of high myopia. Mechanistic evaluations using GFP-positive bone marrow chimeric mice, parabiotic mouse model, enhanced magnetic resonance imaging, etc., show that highly myopic visual stimulation increases CCL2 expression in eyes, aggravates monocyte/macrophage infiltration into eyes and brains, and disrupts blood-ocular barrier and blood-brain barrier of mice. Conversely, Ccl2-deficient highly myopic mice exhibit attenuated ocular and brain infiltration of monocytes/macrophages, reduced disruption of the blood-ocular barrier and blood-brain barrier, and less anxiety. Substantial alleviation of high myopia-related anxiety can also be achieved with the administration of CCL2-neutralizing antibodies. Our results establish the association between high myopia and anxiety, and implicate the CCL2-mediated inflammatory pathogenesis as an underlying mechanism.

Long-Term Outcomes of Posterior Capsular Opacification in Highly Myopic Eyes and Its Influencing Factors

INTRODUCTION

The purpose of this study was to evaluate the long-term outcomes of posterior capsular opacification (PCO) in highly myopic eyes and its influencing factors.

METHODS

Patients undergoing phacoemulsification with intraocular lens implantation and followed up for 1-5 years were included in this prospective cohort study. The severity of PCO was evaluated using EPCO2000 software system, with the area of central 3.0 mm (PCO-3 mm) and within the capsulorhexis (PCO-C) both being analyzed. Percentage of eyes after Nd:YAG capsulotomy, as well as clinically significant PCO (defined as eyes with visual-impairing PCO or after capsulotomy), were also included as outcome variables.

RESULTS

A total of 673 highly myopic eyes [axial length (AL) ≥ 26 mm] and 224 control eyes (AL < 26 mm) were analyzed. The mean follow-up time was 34.0 ± 9.0 months. PCO was more severe in highly myopic eyes compared with controls with regard to higher EPCO scores (P < 0.001 for both PCO-3 mm and PCO-C), higher capsulotomy rate (P = 0.001), higher clinically significant PCO rate (P < 0.001) and shorter PCO-free survival time (P < 0.001). Extreme myopia (AL ≥ 28 mm) would further aggravate PCO in terms of higher EPCO scores (PCO-3 mm: P = 0.017; PCO-C: P = 0.013) and higher clinically significant PCO rate (P = 0.024) compared with other myopic eyes. In highly myopic eyes, AL [odds ratio (OR) 1.124, P = 0.004] and follow-up duration (OR 1.082, P < 0.001) were independent risk factors for clinically significant PCO after cataract surgery.

CONCLUSION

Highly myopic eyes had more severe PCO in the long term. Longer AL and follow-up duration were associated with higher risk of PCO.

CLINICAL TRIAL REGISTRATION

The study was registered at ClinicalTrials.gov (NCT03062085).

Association of Behavioral and Clinical Risk Factors With Cataract: A Two-Sample Mendelian Randomization Study

Purpose

To investigate the association of genetically determined primary open-angle glaucoma (POAG), myopic refractive error (RE), type 2 diabetes (T2D), blood pressure (BP), body mass index (BMI), cigarette smoking, and alcohol consumption with the risk of age-related cataract.

Methods

To assess potential causal effects of clinical or behavioral factors on cataract risk, we conducted two-sample Mendelian randomization analyses. Genetic instruments, based on common genetic variants associated with risk factors at genome-wide significance (P < 5 × 10-8), were derived from published genome-wide association studies (GWAS). For age-related cataract, we used GWAS summary statistics from our previous GWAS conducted in the Genetic Epidemiology Research on Adult Health and Aging (GERA) cohort (28,092 cataract cases and 50,487 controls; all non-Hispanic whites) or in the UK Biobank (31,852 cataract cases and 428,084 controls; all European-descent individuals). We used the inverse-variance weighted (IVW) method as our primary source of Mendelian randomization estimates and conducted common sensitivity analyses.

Results

We found that genetically determined POAG and mean spherical equivalent RE were significantly associated with cataract risk (IVW model: odds ratio [OR] = 1.04; 95% confidence interval [CI], 1.01-1.08; P = 0.018; per diopter more hyperopic: OR = 0.92; 95% CI, 0.89-0.93; P = 6.51 × 10-13, respectively). In contrast, genetically determined T2D, BP, BMI, cigarette smoking, or alcohol consumption were not associated with cataract risk (P > 0.05).

Conclusions

Our results provide evidence that genetic risks for POAG and myopia may be causal risk factors for age-related cataract. These results are consistent with previous observational studies reporting associations of myopia with cataract risk. This information may support population cataract risk stratification and screening strategies.

Building prediction models of clinically significant intraocular lens tilt and decentration for age-related cataract

PURPOSE

To explore the risk factors and construct nomogram models to predict the risks of clinically significant intraocular lens (IOL) tilt and decentration after cataract surgery in patients with age-related cataract.

SETTING

Zhongshan Ophthalmic Center, Guangzhou, China.

DESIGN

Prospective cohort study.

METHODS

207 patients (207 eyes) who underwent phacoemulsification combined with IOL implantation were enrolled in the study. Casia2 was used to measure the tilt and decentration of crystalline lenses and IOLs before and 3 months after surgery. Univariate and multivariate logistic regression analyses were used to determine the risk factors of clinically significant IOL tilt and decentration, and nomogram prediction models were constructed according to the results of the multivariate logistic regression analysis.

RESULTS

Two hundred and seven patients were included in analysis. 24 eyes (11.59%) and 16 eyes (7.73%) had clinically significant IOL tilt and decentration at 3 months after cataract surgery. Multivariate logistic regression analysis revealed that preoperative crystalline lens tilt and decentration were the risk factors for clinically significant IOL tilt (odds ratio [OR], 3.519, P < .001) and decentration (OR, 410.22, P = .001), respectively. Axial length was another association factor for clinically significant IOL decentration (OR, 2.155, P = .019). The risk models demonstrated good calibrations and discriminations for the predictions of clinically significant IOL tilt (receiver operating characteristic [ROC] area = 0.833, cutoff value = 6.5) and decentration (ROC area = 0.757, cutoff value = 0.08).

CONCLUSIONS

The good performances of our models suggested that they may be useful risk prediction tools for postoperative IOL tilt and decentration. The measurement of preoperative crystalline lens tilt and decentration should be one of the routine examinations before cataract surgery, especially for toric and multifocal IOLs.

Applications of Genomics and Transcriptomics in Precision Medicine for Myopia Control or Prevention

Myopia is a globally emerging concern accompanied by multiple medical and socio-economic burdens with no well-established causal treatment to control thus far. The study of the genomics and transcriptomics of myopia treatment is crucial to delineate disease pathways and provide valuable insights for the design of precise and effective therapeutics. A strong understanding of altered biochemical pathways and underlying pathogenesis leading to myopia may facilitate early diagnosis and treatment of myopia, ultimately leading to the development of more effective preventive and therapeutic measures. In this review, we summarize current data about the genomics and transcriptomics of myopia in human and animal models. We also discuss the potential applicability of these findings to precision medicine for myopia treatment.

Prevalence and Characteristics of Myopia in Adult Rhesus Macaques in Southwest China

Purpose

To investigate the prevalence of myopia in a large cohort of adult rhesus macaques at Yunnan Province in southwest China and describe the characteristics of myopic rhesus macaque eyes.

Methods

A total of 219 rhesus macaques 14.07 ± 2.72 years old (range, 8-21) were randomly recruited for this study. We performed fundus photography and measurements of cycloplegic refractive error (RE) and axial length (AL) on macaques.

Results

A total of 429 eyes of 219 macaques were examined. The median RE was -1.25 diopters (D), and the median AL was 18.69 mm. The prevalence of myopia was 62.47%, and one-third of the myopic eyes were highly myopic. The presence of fundus tessellations was higher in myopic eyes than non-myopic eyes (42.54% vs. 6.21%). The cutoff value for the presence of tessellations was -3.52 D for RE and 19.38 mm for AL. In myopic eyes, there were significant differences between grade 1 and grade 3 fundus tessellations on RE (-5.57 ± 2.97 D vs. -8.13 ± 3.51 D) and AL (19.66 ± 0.55 mm vs. 20.60 ± 1.06 mm). Beta-peripapillary atrophy (β-PPA) was found in 48.10% of myopic eyes and 6.83% of non-myopic eyes. The presence of β-PPA is associated with the presence of fundus tessellations, AL, and RE. The presence of β-PPA was higher in grade 3 than grade 1 fundus tessellations (94.4% vs. 76%).

Conclusions

More than half of adult rhesus macaques in southwest China are myopic, and one-third of the myopic ones are highly myopic. Similar to humans, tessellated fundi and β-PPA are the characteristic signs of myopic rhesus macaques. Adult rhesus macaques are optimal animal models for research on the pathogenesis of myopia.

Translational Relevance

This study not only provides a reference for the refractive state and AL in myopic rhesus macaques but also indicates that adult rhesus macaques with spontaneous myopia are optimal animal models for research on the pathogenesis of myopia.

C1Q labels a highly aggressive macrophage-like leukemia population indicating extramedullary infiltration and relapse

Extramedullary infiltration (EMI) is a concomitant manifestation that may indicate poor outcome of acute myeloid leukemia (AML). The underlying mechanism remains poorly understood and therapeutic options are limited. Here, we employed single-cell RNA sequencing on bone marrow (BM) and EMI samples from a patient with AML presenting pervasive leukemia cutis. A complement C1Q+ macrophage-like leukemia subset, which was enriched within cutis and existed in BM before EMI manifestations, was identified and further verified in multiple patients with AML. Genomic and transcriptional profiling disclosed mutation and gene expression signatures of patients with EMI that expressed high levels of C1Q. RNA sequencing and quantitative proteomic analysis revealed expression dynamics of C1Q from primary to relapse. Univariate and multivariate analysis demonstrated adverse prognosis significance of C1Q expression. Mechanistically, C1Q expression, which was modulated by transcription factor MAF BZIP transcription factor B, endowed leukemia cells with tissue infiltration ability, which could establish prominent cutaneous or gastrointestinal EMI nodules in patient-derived xenograft and cell line-derived xenograft models. Fibroblasts attracted migration of the C1Q+ leukemia cells through C1Q-globular C1Q receptor recognition and subsequent stimulation of transforming growth factor β1. This cell-to-cell communication also contributed to survival of C1Q+ leukemia cells under chemotherapy stress. Thus, C1Q served as a marker for AML with adverse prognosis, orchestrating cancer infiltration pathways through communicating with fibroblasts and represents a compelling therapeutic target for EMI.

Single-cell RNA sequencing: Inhibited Notch2 signalling underlying the increased lens fibre cells differentiation in high myopia

High myopia is the leading cause of blindness worldwide. It promotes the overgrowth of lens, which is an important component of ocular refractive system, and increases the risks of lens surgery. While postnatal growth of lens is based on the addition of lens fibre cells (LFCs) supplemented by proliferation and differentiation of lens epithelial cells (LECs), it remains unknown how these cellular processes change in highly myopic eyes and what signalling pathways may be involved. Single-cell RNA sequencing was performed and a total of 50,375 single cells isolated from the lens epithelium of mouse highly myopic and control eyes were analysed to uncover their underlying transcriptome atlas. The proportion of LFCs was significantly higher in highly myopic eyes. Meanwhile, Notch2 signalling was inhibited during lineage differentiation trajectory towards LFCs, while Notch2 predominant LEC cluster was significantly reduced in highly myopic eyes. In consistence, Notch2 was the top down-regulated gene identified in highly myopic lens epithelium. Further validation experiments confirmed NOTCH2 downregulation in the lens epithelium of human and mouse highly myopic eyes. In addition, NOTCH2 knockdown in primary human and mouse LECs resulted in enhanced differentiation towards LFCs accompanied by up-regulation of MAF and CDKN1C. These findings indicated an essential role of NOTCH2 inhibition in lens overgrowth of highly myopic eyes, suggesting a therapeutic target for future interventions.

The lens epithelium as a major determinant in the development, maintenance, and regeneration of the crystalline lens

The crystalline lens is a transparent and refractive biconvex structure formed by lens epithelial cells (LECs) and lens fibers. Lens opacity, also known as cataracts, is the leading cause of blindness in the world. LECs are the principal cells of lens throughout human life, exhibiting different physiological properties and functions. During the embryonic stage, LECs proliferate and differentiate into lens fibers, which form the crystalline lens. Genetics and environment are vital factors that influence normal lens development. During maturation, LECs help maintain lens homeostasis through material transport, synthesis and metabolism as well as mitosis and proliferation. If disturbed, this will result in loss of lens transparency. After cataract surgery, the repair potential of LECs is activated and the structure and transparency of the regenerative tissue depends on postoperative microenvironment. This review summarizes recent research advances on the role of LECs in lens development, homeostasis, and regeneration, with a particular focus on the role of cholesterol synthesis (eg., lanosterol synthase) in lens development and homeostasis maintenance, and how the regenerative potential of LECs can be harnessed to develop surgical strategies and improve the outcomes of cataract surgery (Fig. 1). These new insights suggest that LECs are a major determinant of the physiological and pathological state of the lens. Further studies on their molecular biology will offer possibility to explore new approaches for cataract prevention and treatment.

Altered time-varying local spontaneous brain activity pattern in patients with high myopia: a dynamic amplitude of low-frequency fluctuations study

PURPOSE

To investigate the abnormal time-varying local spontaneous brain activity in patients with high myopia (HM) on the basis of the dynamic amplitude of low-frequency fluctuations (dALFF) approach.

METHODS

Age and gender matching were performed based on resting-state functional magnetic resonance imaging data from 86 HM patients and 87 healthy controls (HCs). Local spontaneous brain activities were evaluated using the time-varying dALFF method. Support vector machine combined with the radial basis function kernel was used for pattern classification analysis.

RESULTS

Inter-group comparison between HCs and HM patients has demonstrated that dALFF variability in the left inferior frontal gyrus (orbital part), left lingual gyrus, right anterior cingulate and paracingulate gyri, and right calcarine fissure and surrounding cortex was decreased in HM patients, while increased in the left thalamus, left paracentral lobule, and left inferior parietal (except supramarginal and angular gyri). Pattern classification between HM patients and HCs displayed a classification accuracy of 85.5%.

CONCLUSION

In this study, the findings mentioned above have suggested the association between local brain activities of HM patients and abnormal variability in brain regions performing visual sensorimotor and attentional control functions. Several useful information has been provided to elucidate the mechanism-related alterations of the myopic nervous system. In addition, the significant role of abnormal dALFF variability has been highlighted to achieve an in-depth comprehension of the pathological alterations and neuroimaging mechanisms in the field of HM.

Lrpap1 deficiency leads to myopia through TGF-β-induced apoptosis in zebrafish

BACKGROUND

Frameshift mutations in LRPAP1 are responsible for autosomal recessive high myopia in human beings but its underlying mechanism remains elusive. This study aims to investigate the effect of LRPAP1 defect on ocular refractive development and its involved mechanism.

METHODS

A lrpap1 mutant zebrafish line with homozygous frameshift mutation was generated by CRISPR/Cas9 technology and confirmed by Sanger sequencing. The ocular refractive phenotype was analyzed by calculating the relative refractive error (RRE) with vivo photography and histological analysis at different development stages, together with examining ocular structure change via transmission electron microscopy. Further, RNA sequencing and bioinformatics analysis were performed. The potentially involved signaling pathway as well as the interacted protein were investigated in vivo.

RESULTS

The lrpap1 homozygous mutant zebrafish line showed myopic phenotype. Specifically, the mutant lines showed larger eye axial length-to-body length in one-month old individuals and a myopic shift with an RRE that changed after two months. Collagen fibers became thinning and disordered in the sclera. Further, RNA sequencing and bioinformatics analysis indicated that apoptosis signaling was activated in mutant line; this was further confirmed by acridine orange and TUNEL staining. Moreover, the expression of TGF-β protein was elevated in the mutant lines. Finally, the treatment of wild-type embryos with a TGF-β agonist aggravated the degree of eyeball apoptosis; conversely, the use of a TGF-β inhibitor mitigated apoptosis in mutant embryos.

CONCLUSION

The study provides functional evidence of a link between lrpap1 and myopia, suggesting that lrpap1 deficiency could lead to myopia through TGF-β-induced apoptosis signaling. Video abstract.

Genome-wide methylation analyses of human sperm unravel novel differentially methylated regions in asthenozoospermia

Aims & objectives: To investigate DNA methylation patterns in asthenozoospermic and normozoospermic sperm and to explore the potential roles of differential methylations in the etiology of the disease. Materials & methods: The authors performed whole-genome bisulfite sequencing analysis between normozoospermic controls and asthenozoospermic individuals. Results: The authors identified 238 significant differentially methylated regions. These differentially methylated regions were annotated to 114 protein-coding genes, with many genes showing associations with spermatogenesis, sperm motility etc. Conclusion: There are plenty of genomic regions exhibiting altered DNA methylation in asthenozoospermia, a number of which are located within or adjacent to sperm-related genes, suggesting novel methylation markers of asthenozoospermia and potential epigenetic regulation mechanisms through DNA methylation in the disease.

Corneal Biometric Features and Their Association With Axial Length in High Myopia

PURPOSE

To characterize the morphologic features of corneal parameters and their correlation with axial length (AL) elongation in patients with high axial myopia.

DESIGN

Cross-sectional comparative study.

METHODS

A total of 299 eyes with high myopia (299 patients) and 266 eyes of age- and sex-matched control subjects (266 patients) were examined by anterior segment swept-source optical coherence tomography (SS-OCT) and an IOL Master. Central corneal thickness (CCT), thinnest corneal thickness (TCT), corneal volume (CV), and anterior corneal curvature (CC), posterior CC, and total CC were obtained, and their correlation with AL was investigated using multiple linear regression model.

RESULTS

The CCT, TCT, CV, and anterior, posterior, and total CC of patients with high myopia were smaller than those of the control subjects. The CCT, TCT, and CV had a continuous downward trend with AL. However, CC decreased rapidly with AL when AL was <26 mm and the slope decreased when AL was 26 to 28 mm. This linear association was absent when AL was >28 mm. Multiple linear regression showed that the CCT (β = -1.98, P = .007), TCT (β = -1.63, P = .019), and CV (β = -0.13, P = .001) were associated with AL. Anterior, posterior, and total CCs were negatively associated with AL when AL was <26 mm (all P < .001) and when AL was between 26 and 28 mm (all P < .05).

CONCLUSIONS

CC decreases may serve as a refractive compensation on myopia when AL is <28 mm. However, this effect does not exist when AL is >28 mm. Consideration should be given to the special distribution of cornea curvature for IOL calculations in subjects with high myopia.

Next-Generation Sequencing Screening of 43 Families with Non-Syndromic Early-Onset High Myopia: A Clinical and Genetic Study

Early-onset high myopia (EoHM) is a disease that causes a spherical refraction error of ≥-6 diopters before 10 years of age, with potential multiple ocular complications. In this article, we report a clinical and genetic study of 43 families with EoHM recruited in our center. A complete ophthalmological evaluation was performed, and a sample of peripheral blood was obtained from proband and family members. DNA was analyzed using a customized next-generation sequencing panel that included 419 genes related to ophthalmological disorders with a suspected genetic cause, and genes related to EoHM pathogenesis. We detected pathogenic and likely pathogenic variants in 23.9% of the families and detected variants of unknown significance in 76.1%. Of these, 5.7% were found in genes related to non-syndromic EoHM, 48.6% in genes associated with inherited retinal dystrophies that can include a syndromic phenotype, and 45.7% in genes that are not directly related to EoHM or retinal dystrophy. We found no candidate genes in 23% of the patients, which suggests that further studies are needed. We propose a systematic genetic analysis for patients with EoHM because it helps with follow-up, prognosis and genetic counseling.

Identification of the Potential Key Genes and Pathways Involved in Lens Changes of High Myopia

Aim

Methods

Results

Conclusion

Geometry of Acrylic, Hydrophobic IOLs and Changes in Haptic-Capsular Bag Relationship According to Compression and Different Well Diameters: A Bench Study Using Computed Tomography

Introduction

Characteristics of the haptics and optic–haptic junction (OHJ) of an intraocular lens (IOL) affect IOL position in the capsular bag, positional stability, and the development of posterior capsule opacification. Therefore, the haptics and OHJ have a role in determining initial and long-term visual outcomes after cataract surgery. Understanding differences in the haptics and OHJ of available IOLs and in the relationships between the haptics of each IOL and the capsular bag across a range of capsular bag sizes might inform selection of an IOL model for individuals.

Purpose

To evaluate the geometry of five currently marketed, commonly used one-piece hydrophobic acrylic monofocal IOLs and changes in haptic–capsular bag relationships according to capsular bag size using a range of compression well diameters.

Methods

AcrySof SN60WF, CT LUCIA 621PY, enVista MX60, TECNIS ZCB00, and Vivinex XY1 IOLs were scanned with computed tomography (CT) in a dry, uncompressed state for quantitative analyses of haptic and OHJ dimensions and qualitative assessment of geometry. CT scanning was done after IOL placement into a series of compression wells (11.5, 11.0, 10.0, and 9.0 mm) for analyses of haptic angle of contact (AoC) and capsular bag contact (CBC). IOL axial alignment and haptic–capsular bag relationships were assessed on side-view and 3-dimensional top-view images, respectively.

Results

The qualitative and quantitative evaluations highlighted differences in haptic and OHJ geometry and dimensions across the five IOLs. All haptic dimensions (length, thickness, surface area, volume) and all OHJ dimensions (surface area and volume) were greatest for the CT LUCIA 621PY IOL. Compared to the IOL that had the smallest measurement for each parameter, the value for the CT LUCIA 621PY IOL was 31–91% larger. The lens with the largest OHJ surface area and volume showed values that were 500% and 240% greater than the corresponding values for the lens with the smallest OHJ surface area and OHJ volume. The AoC and CBC values decreased with increasing well size for all IOLs. The CT LUCIA 621PY had the greatest AoC and CBC values for all well sizes and the smallest percentage change in AoC and CBC comparing the values from the 9.0 mm and 11.5 mm wells.

Conclusion

The in vitro evaluations in this study highlight differences in the haptic and OHJ geometric characteristics of the five IOLs studied. The collected evidence refutes opinions that all hydrophobic acrylic one-piece IOLs are the same and supports the idea that individual IOLs can have relative advantages and disadvantages that depend on the individual case. We believe the knowledge of geometry is necessary for the surgeon to have the opportunity to select the best “customized” option in the individual case as a result of anatomical conditions and secondary diagnoses. Our bench study shows how big the differences are in currently available monofocal hydrophobic acrylic lenses.

Advances in biomedical study of the myopia-related signaling pathways and mechanisms

Myopia has become one of the most critical health problems in the world with the increasing time spent indoors and increasing close work. Pathological myopia may have multiple complications, such as myopic macular degeneration, retinal detachment, cataracts, open-angle glaucoma, and severe cases that can cause blindness. Mounting evidence suggests that the cause of myopia can be attributed to the complex interaction of environmental exposure and genetic susceptibility. An increasing number of researchers have focused on the genetic pathogenesis of myopia in recent years. Scleral remodeling and excessive axial elongating induced retina thinning and even retinal detachment are myopia's most important pathological manifestations. The related signaling pathways are indispensable in myopia occurrence and development, such as dopamine, nitric oxide, TGF-β, HIF-1α, etc. We review the current major and recent progress of biomedicine on myopia-related signaling pathways and mechanisms.