Limited bandwidth short-wavelength light produces slowly-developing myopia in tree shrews similar to human juvenile-onset myopia

Khanal, Safal; Norton, Thomas T.; Gawne, Timothy J.

doi:10.1016/j.visres.2022.108161

Cited by 10 publications

(3 citation statements)

References 80 publications

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“…Of further concern, digital devices emit high levels of narrow band shortwavelength light, 46 which results in instability in refraction trending to myopia. 47 In the present study, premyopia was strongly associated with parental myopia, whereas myopia was not. This finding is unexpected as early-onset myopia is typically considered genetic.…”

Section: Discussionsupporting

confidence: 39%

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The association between time spent on screens and reading with myopia, premyopia and ocular biometric and anthropometric measures in 6‐ to 7‐year‐old schoolchildren in Ireland

Harrington

O’Dwyer

2023

Ophthalmic Physiologic Optic

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More time spent on near tasks has consistently been associated with the promotion of myopia. The World Health Organization advises limiting daily screentime to less than 2 h for children aged five and over. This study explored the relationship between time spent on screens and reading/writing with refractive status, ocular biometric and anthropometric factors in 6-to 7-year-olds in Ireland. Methods: Participants were 723 schoolchildren (377 boys [51.8%]), mean age 7.08 (0.45) years. The examination included cycloplegic autorefraction (1% cyclopentolate hydrochloride), ocular biometry (Zeiss IOLMaster), height (cm) and weight (kg). Screentime and reading/writing time were reported by parents/legal guardians by questionnaire. Myopia (≤−0.50D) and premyopia (>−0.50D ≤ 0.75D) risk assessments were performed using logistic regression, and multivariate linear regression was used to analyse continuous variables. Results: Reported daily screentimes were 31% <1 h, 49.5% 1-2 h, 15.6% 2-4 h and 3.9% >4 h. Reading/writing times were 42.2% frequently, 48.0% infrequently and 9.8% seldom/never. Linear regression, controlling for age and ethnicity, revealed >2 h/day on screens was associated with a more myopic spherical equivalent [β = −1.15 (95% confidence intervals {CIs}: 1.62-0.69, p < 0.001)], increased refractive astigmatism (β = 0.29, CI: 0.06-0.51, p = 0.01), shorter corneal radius (β = 0.12, CI: 0.02-0.22, p = 0.02), higher axial length/corneal radius (β = 0.06, CI: 0.03-0.09, p < 0.001), heavier weight (β = 1.60, CI: 0.76-2.45, p < 0.001) and higher body mass index (BMI) (β = 1.10, CI: 0.28-1.12, p < 0.001). Logistic regression, controlling for age and ethnicity, revealed daily screentime >2 h was associated with myopia (OR = 10.9, CI: 4.4-27.2, p = 0.01) and premyopia (OR = 2.4, CI: 1.5-3.7, p < 0.001). Frequent reading/writing was associated with screentime ≤2 h/day (OR = 3.2, CI: 1.8-5.8, p < 0.001). Conclusion: Increased screentime was associated with a more myopic refraction, higher axial length/corneal radius ratio, increased odds of myopia, premyopia, higher degrees of astigmatism, increased weight, BMI and decreased reading/writing time. Dedicated education programmes promoting decreased screentime in children are vital to prevent myopia and support eye and general health.

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Section: Discussionsupporting

confidence: 39%

“…Hence, those in the higher screentime categories may be more susceptible to myopia development during the period of faster axial elongation around 8–11 years. Of further concern, digital devices emit high levels of narrow band short‐wavelength light, 46 which results in instability in refraction trending to myopia 47 …”

Section: Discussionmentioning

confidence: 99%

The association between time spent on screens and reading with myopia, premyopia and ocular biometric and anthropometric measures in 6‐ to 7‐year‐old schoolchildren in Ireland

Harrington

O’Dwyer

2023

Ophthalmic Physiologic Optic

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“…We have hypothesized that in children developing myopia, the spatial/chromatic/temporal visual environment across the day is not sufficient to allow the retina to generate quite enough STOP to prevent a slow drift into myopia. 66 This could explain why under-correction of a prescription does not seem to work 67 , 68 : if the visual environment is impairing the ability of emmetropization to evaluate focus, it will do so across the range of defocus. Current optical anti-myopia therapies, such as multifocal contact lenses, 9 seem to require wearing during a large fraction of the day, but these therapies only slightly alter the retinal image.…”

Section: Discussionmentioning

confidence: 99%

The Parameters Governing the Anti-Myopia Efficacy of Chromatically Simulated Myopic Defocus in Tree Shrews

She,

Gawne

2024

Trans. Vis. Sci. Tech.

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Purpose We previously showed that exposing tree shrews ( Tupaia belangeri , small diurnal mammals closely related to primates) to chromatically simulated myopic defocus (CSMD) counteracted small-cage myopia and instead induced hyperopia (approximately +4 diopters [D]). Here, we explored the parameters of this effect. Methods Tree shrews were exposed to the following interventions for 11 days: (1) rearing in closed ( n = 7) or open ( n = 6) small cages; (2) exposed to a video display of Maltese cross images with CSMD combined with overhead lighting ( n = 4); (3) exposed to a video display of Maltese cross images with zero blue contrast (“flat blue,” n = 8); and (4) exposed to a video display of black and white grayscale tree images with different spatial filtering (blue pixels lowpass <1 and <2 cycles per degree [CPD]) for the CSMD. Results (1) Tree shrews kept in closed cages, but not open cages, developed myopia. (2) Overhead illumination reduced the hyperopia induced by CSMD. (3) Zero-blue contrast produced hyperopia but slightly less than the CSMD. (4) Both of the CSMD tree images counteracted small cage myopia, but the one low pass filtering blue <1 CPD was more effective at inducing hyperopia. Conclusions Any pattern with reduced blue contrast at and below approximately 1 CPD counteracts myopia/promotes hyperopia, but maximal effectiveness may require that the video display be the brightest object in the environment. Translational Relevance Chromatically simulated myopic blur might be a powerful anti-myopia therapy in children, but the parameter selection could be critical. Issues for translation to humans are discussed.

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Animal models as windows into the pathogenesis of myopia: Illuminating new directions for vision health

Chi,

Jiao,

et al. 2024

Biochemical and Biophysical Research Communications

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Limited bandwidth short-wavelength light produces slowly-developing myopia in tree shrews similar to human juvenile-onset myopia

Cited by 10 publications

References 80 publications

The association between time spent on screens and reading with myopia, premyopia and ocular biometric and anthropometric measures in 6‐ to 7‐year‐old schoolchildren in Ireland

The association between time spent on screens and reading with myopia, premyopia and ocular biometric and anthropometric measures in 6‐ to 7‐year‐old schoolchildren in Ireland

The Parameters Governing the Anti-Myopia Efficacy of Chromatically Simulated Myopic Defocus in Tree Shrews

Animal models as windows into the pathogenesis of myopia: Illuminating new directions for vision health

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