Light Intensity in Nursery Schools: A Possible Factor in Refractive Development

Abstract

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 AE 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 AE 2.64 lux (range 264-431), 490 AE 2.21 lux (range 432-574), and 670.76 AE 3.73 lux (range 578-804), respectively. Mean spherical equivalent (SE) was þ0.56 AE 0.03D for the low-intensity group, þ0.73 AE 0.03D for the medium-intensity group, and þ0.89 AE 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.

Association between whole-grain intake and myopia in chinese children: a cross-sectional epidemiological study

“…Among the associated factors for myopia in the multivariable logistic regression analysis, we were particularly surprised by the markedly lower prevalence of myopia in the participants where classroom curtains were often open. This would be consistent with the light effects reported by Cohen and Iribarren [ 33 ]. The link between light exposure and the prevalence of myopia has not been fully elucidated; however, the proposed reasons include factors such as variations in chromatic light composition, higher light intensities, and increased release of dopamine from the retina, which can slow axial elongation [ 34 – 38 ].…”

China Turns to School Reform to Control the Myopia Epidemic: A Narrative Review

“…46 One paper from China has reported major preventive effects of increasing light intensities in classrooms, 47 and one of the papers in this special issue reports on the deleterious effects of low light intensities in kindergarten classrooms. 48 If confirmed, these observations offer some simple interventions to control myopia, ranging from a prototype bright classroom, 49 to systematic upgrades of schoolroom lighting. Light intensity may not be the only important parameter, and a recent paper has reported that repeated exposure to low-level red-light in a clinical situation also has the ability to prevent the progression of myopia.…”

“…The importance of light exposures during time outdoors has revived interest in lighting conditions in schoolrooms 46 . One paper from China has reported major preventive effects of increasing light intensities in classrooms, 47 and one of the papers in this special issue reports on the deleterious effects of low light intensities in kindergarten classrooms 48 . If confirmed, these observations offer some simple interventions to control myopia, ranging from a prototype bright classroom, 49 to systematic upgrades of schoolroom lighting.…”

Refractive development I: Biometric changes during emmetropisation

“…7 Much remains unclear about how the retinal image quality is integrated over time into growth signals that may vary locally between different parts of the retina. 334 Here, the environmental luminosity 335 and spatial frequencies 336 play an essential role as the optical quality of a system is best estimated using a brightly lit, high-contrast target.…”