Credit: Cottonbro Studio

Researchers in China have found 15 minutes of intense sunlight exposure restored fundus blood flow perfusion (BFP) in young myopes following an hour of indoor near-work.

Altered fundus blood flow is believed to play a role in the pathogenesis of myopia and can serve as a predictive indicator for myopia development, said researchers. “Clinical studies have demonstrated that individuals with myopia often exhibit diminished choroidal and retinal BFP, contributing to scleral hypoxia and subsequent myopia progression.”

Writing in the British Journal of Ophthalmology, the researchers at Shanghai’s Tongji University recruited 81 students aged 7-15 with spherical equivalent refraction between -2.00 and +3.00 diopters. After an hour of indoor reading, participants were randomly exposed to either low-illuminance (4k lux) or high-illuminance (10k lux) for 15 minutes. Within the first five minutes of sunlight exposure, the 10k lux group showed a tendency for decreased BFP, particularly in the choroid, while the 4k lux group exhibited an increase, the team reported.

Noting duration was critical, they concluded exposure to continuous higher intensity sunlight could efficiently contribute to the recovery of BFP after near work. “BFP in the retina and choroid gradually returned to their pre-reading status after continuous exposure to sunlight for 15 minutes, particularly notable in the choroid BFP for both the 10k-lux and 4k-lux groups.”