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Light Intensity in Nursery Schools: A Possible Factor in Refractive Development
Yuval Cohen1,2, Rafael Iribarren3, Hadas Ben-Eli4,5
1Department of Ophthalmology, Ziv Medical Center, Safed, Israel.
Insights
Lower indoor nursery light intensity in preschool children was linked to less hyperopic refractive error. This finding suggests a potential avenue for myopia prevention strategies through light modulation.
Area of Science:
- Ophthalmology
- Pediatric Optometry
- Environmental Health
Background:
- Increased outdoor light exposure is causally linked to reduced myopia rates.
- Understanding indoor light's impact on refractive error is crucial for early-life eye health.
Purpose of the Study:
- To investigate the association between indoor nursery school light intensity and refractive error in preschool children.
- To assess if indoor illumination levels influence the refractive status of young children in Israel.
Main Methods:
- 1596 preschool children (4-5 years) from 27 nursery schools participated.
- Light intensity was measured in lux indoors and outdoors.
- Non-cycloplegic refractions were obtained using the PlusOptix A09 screening device.
Main Results:
- Mean spherical equivalent (SE) was +0.56D (low light), +0.73D (medium light), and +0.89D (high light).
- Lower light intensity groups showed a higher percentage of children with zero or less refractive error (42.1% vs 19.3%).
- Significant differences in refractive error across light intensity groups were observed (ANOVA P < 0.001).
Conclusions:
- Lower indoor illumination levels in nursery schools correlated with less hyperopic refractive error.
- A reduced hyperopic reserve is a known risk factor for myopia development.
- Further research is needed to confirm causality and explore light modulation for myopia prevention.
Purpose:
Increased levels of outdoor light have been found to be associated causally with decreased rates of myopia. The goal of this study was to measure the effect of indoor nursery school light intensity on refraction of preschool children in Israel.
Methods:
A total of 1596 children aged 4 to 5 years from 27 nursery schools were examined. Light intensity was tested with a luxmeter device (Lux) inside and outside the nursery school. Noncycloplegic refractions were measured with the PlusOptix vision A09 screening device. Data analysis was performed using Pearson coefficients, chi-square tests for proportions and ANOVA tests by tertiles of illuminance.
Results:
This study included 1131 kindergarten children with a mean age of 4.87 ± 0.33 years, of which 571 were female (50.5%). The mean light intensity of the low, medium, and high intensity groups differed significantly (ANOVA P < 0.001) at 359 ± 2.64 lux (range 264-431), 490 ± 2.21 lux (range 432-574), and 670.76 ± 3.73 lux (range 578-804), respectively. Mean spherical equivalent (SE) was +0.56 ± 0.03D for the low-intensity group, +0.73 ± 0.03D for the medium-intensity group, and +0.89 ± 0.03D for the high-intensity group (ANOVA P < 0.001). The low-intensity group had 42.1% of children with zero refraction or less, while the high-intensity group had 19.3%.
Conclusions:
In the nursery schools, lower amounts of illumination were associated with less hyperopic refractive error. As the low hyperopic reserve is a risk factor for developing myopia, this finding needs to be followed up to establish whether this association reflects a causal relationship, which could be modulated for the prevention of myopia.
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