The Effect of Sun-like Spectrum With Different Spectrum Composition on Retinal Blood Flow

The Effect of Sun-like Spectrum With Different Spectrum Composition on Retinal Blood Flow in School Students: a Randomized Controlled Trial

In 2020, the overall myopia rate among children and adolescents was 52.7% in China. The COVID-19 pandemic has increased students' time of indoor eye-using, and it showed that the light exposure intensity of myopic students is lower than that of non-myopia students. Studies have found that in addition to exposure to light intensity, the occurrence and development of myopia is also related to the color temperature and wavelength band of light. The sun-like spectrum refers to the spectrum with continuous wavelength bands. Animal experiments suggest that sun-like artificial lighting can prevent myopia, but the relationship between sun-like artificial lighting with different color temperatures and myopia is unknown. Clinical trials suggest that artificial lighting with a sun-like spectrum can delay fundus blood flow decline. One hypothesis is that reduced choroidal blood flow leads to scleral hypoxia and promotes the development of myopia. This study aims at comparing the effects of sun-like spectrum artificial lighting with different dominant wavelengths on the human eye, and providing clues for the prevention and control of myopia.

In 2018, eight departments including the Ministry of Education jointly issued the Implementation Plan for Comprehensive Prevention and Control of Myopia in Children and Adolescents. As of 2020, the overall myopia rate among children and adolescents was 52.7% in China. The COVID-19 pandemic has increased students' time of indoor eye-using, and it showed that the light exposure intensity of myopic students is lower than that of non-myopia students. Studies have found that in addition to exposure to light intensity, the occurrence and development of myopia is also related to the color temperature and wavelength band of light. Animal experiments showed that the bandwidth of light had a significant effect on the emmetropia of the eye, and white light can promote emmetropia more than monochromatic light; longer-wavelength light and shorter-wavelength light can promote and inhibit the development of myopia through hyperopia and myopic defocus, respectively. At present, the artificial lighting methods on the market are mainly light emitting diode (LED), whose light spectrum is discontinuous. With the advancement of related research and lighting technology, multiple LED emission peaks and "sun-like spectrum" desk lamps have gradually appeared. The sun-like spectrum refers to the spectrum with continuous wavelength bands. Animal experiments suggest that sun-like artificial lighting can prevent myopia, but the relationship between sun-like artificial lighting with different color temperatures and myopia is unknown. Clinical trials suggest that artificial lighting with a sun-like spectrum can delay fundus blood flow decline. Fundus blood flow is sensitive to myopia stimuli, and is a short-term effect indicator of the relationship between light environment and myopia. One hypothesis is that reduced choroidal blood flow leads to scleral hypoxia and promotes the development of myopia. Therefore, in this study fundus blood flow was selected as the main research indicator, aiming to compare the effects of sun-like spectrum artificial lighting with different dominant wavelengths on the human eye, and provide clues for the prevention and control of myopia.

The participants were randomly divided into the following three groups: Sun-like spectrum, color temperature of 5000K, shorter-wavelength dominant; Sun-like spectrum, color temperature of 5000K, wavelength proportion similar to the sunlight; Sun-like spectrum, color temperature of 5000K, longer-wavelength dominant.

Data were collected from AcomoREF2 (AMF mode, record distance and high-frequency component), for the dominant eye. And the Accommodative response value was documented for further analysis.

Inclusion Criteria: School students aged from 7 to 15, regardless of sex or gender; Diopter between -2.0D and 3.0D, and astigmatism not exceed 0.75D; No organic disease and in good general condition; Have obtained the consent of their parents or guardians, and can cooperate. Exclusion Criteria: Suffering from amblyopia, strabismus, color weakness, congenital cataract, glaucoma and other eye diseases; Other circumstances judged by the investigator to be unsuitable to participate in the research.

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