Mechanisms of emmetropization and what might go wrong in myopia

Vision Research, Journal Year: 2024, Volume and Issue: 220, P. 108402 - 108402

Published: May 4, 2024

Studies in animal models and humans have shown that refractive state is optimized during postnatal development by a closed-loop negative feedback system uses retinal image defocus as an error signal, mechanism called emmetropization. The sensor to detect its sign resides the retina itself. and/or pigment epithelium (RPE) presumably releases biochemical messengers change choroidal thickness modulate growth rates of underlying sclera. A central question arises: if emmetropization operates system, why does it not stop myopia development? Recent experiments young human subjects (1) emmetropic can perfectly distinguish between real positive simulated defocus, trigger transient axial eye shortening or elongation, respectively. (2) Strikingly, myopic has reduced ability inhibit when imposed. (3) bi-directional response elicited with low spatial frequency information below 8 cyc/deg, which makes unlikely optical higher-order aberrations play role. (4) for detection involves comparison blur blue (S-cone) red end spectrum (L + M-cones) but, again, responsive, at least short-term experiments. This suggests cannot fully inhibitory arm loop. As result, open loop, becomes "open-loop".

Language: Английский

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Choroidal thickness, myopia, and myopia control interventions in children: a Meta-analysis and systemic review

International Journal of Ophthalmology, Journal Year: 2023, Volume and Issue: 16(3), P. 453 - 464

Published: March 3, 2023

AIM: To investigate changes of choroidal thickness (ChT) in children with myopia and the effect current control interventions on ChT. METHODS: Major literature databases were searched for studies relevant to children. All used swept-source optical coherence tomography (SS-OCT) or enhanced depth imaging (EDI-OCT) measure ChT value. The weighted mean difference (WMD) 95% confidence interval (CI) pooled evaluate RESULTS: A total 11 eligible articles, including 1693 myopic 1132 non-myopic eyes, included first Meta-analysis. sub-foveal (SFCT; WMD=-40.06, 95%CI, -59.36 -20.75, P<0.001) at other sectors significantly thinner eyes compared eyes. Meta-analysis revealed that decreased horizontally from temporal sector toward nasal pediatric population. Another reporting second relationship between treatments SFCT increased after orthokeratology (OK) treatment OK combined 0.01% atropine (OKA) (WMD=19.47, 15.96 22.98, P<0.001; WMD=21.81, 12.92 29.70, P<0.001, respectively). forest plots showed changed little receiving (P=0.30). Furthermore, had a stronger value as (WMD=9.86; -0.21 19.93, P=0.05). There is no OKA (P=0.37). CONCLUSION: than Myopia lead thickening, but such did not show an increase

Language: Английский

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An Evidence-Based Narrative Review of Scleral Hypoxia Theory in Myopia: From Mechanisms to Treatments

International Journal of Molecular Sciences, Journal Year: 2025, Volume and Issue: 26(1), P. 332 - 332

Published: Jan. 2, 2025

Myopia is one of the dominant causes visual impairment in world. Pathological myopia could even lead to other serious eye diseases. Researchers have reached a consensus that be caused by both environmental and genetic risk factors. Exploring pathological mechanism can provide scientific basis for developing measures delay progression or treat it. Recent advances highlight scleral hypoxia an important factor promoting myopia. In this review, we summarized role pathology also provided interventions target directly indirectly. We hope review will aid development novel therapeutic strategies drugs

Language: Английский

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Choroidal thickening and retinal dopamine increase in mice at high altitude

Experimental Eye Research, Journal Year: 2025, Volume and Issue: 251, P. 110241 - 110241

Published: Jan. 13, 2025

Language: Английский

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GABAB Receptor Activation Affects Eye Growth in Chickens with Visually Induced Refractive Errors

Biomolecules, Journal Year: 2023, Volume and Issue: 13(3), P. 434 - 434

Published: Feb. 24, 2023

This study aims to explore the role of GABAB receptors in development deprivation myopia (DM), lens-induced (LIM) and hyperopia (LIH). Chicks were intravitreally injected with 25 µg baclofen (GABABR agonist) one eye saline into fellow eye. Choroidal thickness (ChT) was measured via OCT before 2, 4, 6, 8, 24 h after injection. ChT decreased strongly at 6 8 injection returned back baseline level h. Moreover, chicks monocularly treated translucent diffusers, −7D or +7D lenses randomly assigned treatment. DM daily both eyes, while LIM LIH lens-wearing for 4 days. Refractive error, axial length Dopamine its metabolites analyzed HPLC. Baclofen significantly reduced myopic shift growth eyes. However, it did not change compared respective saline-injected On other hand, inhibited hyperopic choroidal thickening All baclofen-injected eyes showed lower vitreal DOPAC content. Since GABA is an inhibitory ubiquitous neurotransmitter, interfering signaling affects spatial retinal processing therefore refractive error diffusers lenses.

Language: Английский

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Increase in choroidal thickness after blue light stimulation of the blind spot in young adults

Bioelectronic Medicine, Journal Year: 2024, Volume and Issue: 10(1)

Published: June 3, 2024

Abstract Background Blue light activates melanopsin, a photopigment that is expressed in intrinsically photosensitive retinal ganglion cells (ipRGCs). The axons of ipRGCs converge on the optic disc, which corresponds to physiological blind spot visual field. Thus, blue stimulus aligned with captures at disc. This study examined potential changes choroidal thickness and axial length associated stimulation melanopsin-expressing spot. It was hypothesized adults increases thickness. Methods spots both eyes 10 emmetropes myopes, mean age 28 ± 6 years (SD), were stimulated locally for 1-minute flickering 460 nm peak wavelength. Measurements collected from left eye before over 60-minute poststimulation period. At similar time day, measured under sham control condition all participants, while subset 3 myopes after red wavelength 620 nm. Linear mixed model analyses performed examine light-induced between refractive groups. Results Compared (2 1 μm, n = 20) (−1 2 6) stimulation, subfoveal increased within 60 min (7 20; main effect light, p < 0.001). Significant thickening occurred (10 0.001) but not (4 > 0.05). Choroidal greater fovea, diminishing parafoveal perifoveal regions. There no significant or by error interaction stimulation. Conclusions These findings demonstrate stimulating young adults. has implications regulating growth.

Language: Английский

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Advances in the study of the influence of photoreceptors on the development of myopia

Experimental Eye Research, Journal Year: 2024, Volume and Issue: 245, P. 109976 - 109976

Published: June 17, 2024

Language: Английский

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Refractive Development and Choroidal Vascularity in the Form-Deprivation Pigmented Rabbit Model

Translational Vision Science & Technology, Journal Year: 2025, Volume and Issue: 14(2), P. 18 - 18

Published: Feb. 13, 2025

Purpose: This study assessed the characteristics of refractive development and choroidal vasculature in form-deprivation (FD) pigmented rabbit model. Methods: Monocular FD was performed three-week-old rabbits (n = 18 for FD, n 12 control). Throughout eight-week rearing period, errors, corneal curvature radius (CCR), ocular biometric parameters, retinal thickness (RT), (ChT) were measured every two weeks using cycloplegic retinoscopy, keratometer, A-scan ultrasonography, optical coherence tomography (OCT). The vascularity index (CVI) calculated from OCT images by measuring total area (TCA), stromal (SA), luminal (LA). At end form deprivation, vitreous dopamine level an enzyme-linked immunosorbent assay kit. Results: Relatively myopic refraction induced eyes after two, four, six, eight (interocular differences: −1.48 ± 0.88, −1.92 0.90, −1.95 0.80, −2.00 0.83 diopter; P < 0.001). Furthermore, showed significantly longer axial length (AL) chamber depth weeks, with mean differences 0.32 0.03 0.05 mm, respectively (P There no significant anterior depth, lens thickness, CCR, RT among three groups through intervention (all > 0.05). After average ChT thinner than contralateral (−19.37 7.01 µm; Additionally, TCA, SA, LA smaller 0.05, week 8: 0.3697 0.0639 vs. 0.4272 0.0968, 0.1047 0.0221 0.1233 0.0328, 0.2650 0.0459 0.3039 0.0659 mm2, respectively). However, CVI difference Finally, concentration lower eyes, compared control eyes: 0.18 0.20, 0.40 0.67, 0.33 0.06 ng/mL, Conclusions: Form deprivation led to a relatively shift decrease levels. In addition, lengthening AL, choroid thinned, but remained unchanged. Translational Relevance: Our offered data about investigate myopia mechanisms. modified method imaged inferior species more clearly, achieving exploring changes vivo.

Language: Английский

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Topical review: Potential mechanisms of atropine for myopia control

Optometry and Vision Science, Journal Year: 2025, Volume and Issue: unknown

Published: March 31, 2025

SIGNIFICANCE: Atropine is effective at slowing myopia progression in children, but the mechanism of action by which it controls remains unclear. This article an evidenced-based review potential receptor-based mechanisms atropine may act to slow myopia. The rising number individuals with worldwide and association between vision-threatening ocular pathologies have made control treatments one fastest growing areas ophthalmic research. High-concentration (1%) most treatment for date; low concentrations (≤0.05%) appear partially are currently being used children. While significant progress has been past few decades understanding fundamental myopia, precise characterization how works incomplete. It plausible that slows via its affinity muscarinic receptors influence on accommodation, animal studies suggest this likely not case. Other shown that, addition receptors, can also bind, or affect of, dopamine, alpha-2-adrenergic, gamma-aminobutyric acid, cytokine progression. summarizes atropine’s effects different receptor pathways tissues discusses these contribute Given relatively broad array implicated a single mode unlikely; rather be exerting directly indirectly several multiple levels tissues, all trigger response same direction inhibit eye growth

Language: Английский

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Clinical observation and experimental study on the role of choroid‐to‐retina volume ratio in diabetic retinopathy

Diabetes Obesity and Metabolism, Journal Year: 2025, Volume and Issue: unknown

Published: May 7, 2025

Abstract Aims The retinal blood supply system reserve (RBSSR) reflects the vascular system's capacity to meet increased metabolic demands and may be critical in pathogenesis of diabetic retinopathy (DR). This study aimed clinically measure experimentally validate choroid‐to‐retina volume ratio (CRVR) as an indicator RBSSR DR. Materials Methods Diabetic patients were divided into NDR group (no apparent retinopathy, 134 eyes) DR (nonproliferative DR, 125 cross‐sectional survey. Optical coherence tomography angiography (OCTA) 12 × mm 2 fovea‐centred scans performed on subjects. Retinal choroidal parameters automatically measured, CRVR was analysed. Atropine eye drops used for C57BL/6J mice modelling, examined by OCTA. Early mouse models subsequently induced streptozotocin, fundus structural changes well apoptosis examined. Results exhibited significantly lower than (all p < 0.05). Logistic regression analysis area under ROC curve (AUC) indicate that low is a risk factor with all AUC values exceeding 0.70. Compared controls, atropine mice. Additionally, eyes treated fewer punctate hyperfluorescent lesions, tighter arrangement outer nuclear layer (ONL), reduced ONL pigment epithelium early models. Conclusions supports existence suggests can serve potential RBSSR, highlighting its role pathogenesis.

Language: Английский

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