Clinical trial NCT05594732: The Effects of Different Outdoor Light Exposure Modes on Retinal Blood Flow
Official title: The Effects of Different Outdoor Light Exposure Modes on Retinal Blood Flow in School Students: a Randomized Controlled Trial
Study type: INTERVENTIONAL
Overall status: COMPLETED
Phase: NA
Conditions: Myopia
Keywords: myopia
retinal blood flow
accommodative micro-fluctuation
outdoor light exposure
Lead sponsor: Shanghai Eye Disease Prevention and Treatment Center
Sponsor class: OTHER
First posted: 2022-10-26
Enrollment: 81
Sex: ALL
Minimum age (years): 7
Maximum age (years): 15
Standard ages: CHILD
Accepts healthy volunteers: no
Allocation: RANDOMIZED
Intervention model: PARALLEL
Intervention model description: The participants were randomly divided into the following two groups:

1. 4000Lux natural light exposure;
2. 10000Lux natural light exposure.
Primary purpose: PREVENTION

Brief summary: In 2020, the overall myopia rate among children and adolescents in my country was 52.7%. 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 the light wave bandwidth has a significant impact on the emmetropization of the eye, and white light can promote emmetropia more than monochromatic light. It shows that outdoor exercise has a protective effect on the occurrence and development of myopia in children and adolescents, but the specific mechanism is still unclear. Retinal blood flow is sensitive to myopic stimuli, and is a short-term indicator of the relationship between light environment and myopia. This study selected retinal blood flow as the primary outcome, aiming to compare the effects of different outdoor light exposure modes on retinal blood flow after 1 hour of intense eye use, and provide clues for the prevention and control of myopia.

Detailed description: 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 in my country was 52.7%. 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 the light wave bandwidth has a significant impact on the emmetropization of the eye, and white light can promote emmetropia more than monochromatic light. It shows that outdoor exercise has a protective effect on the occurrence and development of myopia in children and adolescents, but the specific mechanism is still unclear. Retinal blood flow is sensitive to myopic stimuli, and is a short-term indicator of the relationship between light environment and myopia. Also, there is a theory that reduced choroidal blood flow causes scleral hypoxia, which leads to the development of myopia. Therefore, this study selected retinal blood flow as the primary outcome, aiming to compare the effects of different outdoor light exposure modes on retinal blood flow after 1 hour of intense eye use, and provide clues for the prevention and control of myopia.

Eligibility criteria: 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.

Primary outcomes:
measure: Retinal blood flow density after relaxing for 15 minutes
timeFrame: Exposing to sunlight for 15 minutes
Secondary outcomes:
measure: Retinal blood flow density changes between relaxing for 5 and 15 minutes
timeFrame: Retinal blood flow density after relaxing for 5 and 15 minutes
Other outcomes:
Locations:
city: Shanghai
country: China
facility: Shanghai Eye Disease Prevention and Treatment Center
state: Shanghai
Study officials:
affiliation: Shanghai Eye Hospital
name: Xiangui He
role: PRINCIPAL_INVESTIGATOR
References:
citation: Mirhajianmoghadam H, Pina A, Ostrin LA. Objective and Subjective Behavioral Measures in Myopic and Non-Myopic Children During the COVID-19 Pandemic. Transl Vis Sci Technol. 2021 Sep 1;10(11):4. doi: 10.1167/tvst.10.11.4.
citation: Rucker F. Monochromatic and white light and the regulation of eye growth. Exp Eye Res. 2019 Jul;184:172-182. doi: 10.1016/j.exer.2019.04.020. Epub 2019 Apr 21.
citation: Xiong S, Sankaridurg P, Naduvilath T, Zang J, Zou H, Zhu J, Lv M, He X, Xu X. Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. Acta Ophthalmol. 2017 Sep;95(6):551-566. doi: 10.1111/aos.13403. Epub 2017 Mar 2.
citation: Liu Y, Wang L, Xu Y, Pang Z, Mu G. The influence of the choroid on the onset and development of myopia: from perspectives of choroidal thickness and blood flow. Acta Ophthalmol. 2021 Nov;99(7):730-738. doi: 10.1111/aos.14773. Epub 2021 Feb 7.