Abstract
Purpose :
Given the potential role of light and its wavelength on ocular growth, this study aimed to investigate the effect of short-term exposure to short, middle, and long-wavelength on axial elongation in presence of ocular defocus.
Methods :
A total of 7 young adults (4 emmetropes, 3 myopes) were exposed to long (red-623nm), middle (green-521 nm), and short-wavelength of light (blue-460 nm) for a period of 60 minutes each on 3 separate days (between 9 to 11 am). During the light exposure, monocular (right eye) hyperopic defocus of 3D was induced to the right eye with the fellow eye experience normal view (no defocus). The mean (± SD) age of the participants was 23 ± 3 years and spherical equivalent refractive error ranged from -+0.50 to +-2.50 D). Smart LED Bulb ((Wipro Enterprises Ltd., Shezhen,PRC, China) was used in a 3x3x3 meters closed room while the participants were asked to watch the video placed at 3 meters from the eye for the experiment period of 60 minutes. Axial length was recorded pre and post the defocus (in less than a minute) using Lenstar non-contact biometer. Participants were asked to score asthenopic symptoms (headache, eye strain, eye discomfort, eye fatigue, dizziness) after the experiment as none, slight, moderate, severe, intolerable.
Results :
There was a small but significant increase in axial length from baseline in the right eye (with defocus) after 1- hour exposure to longer (13±4 µ, p =0.02) and middle wavelength of light (16±5 µ, p = 0.01), but not with the shorter wavelength (0±4 µ, p= 0.49). Emmetropes showed greater axial elongation compared to myopes in both red and green light conditions. Exposure to middle wavelength alone lead to significant changes in axial length in the left eye (9±2 µ, p = 0.01). None of the participants experienced/complained of any asthenopic symptoms during or after the experiment.
Conclusions :
One hour exposure to the shorter wavelength of light did not lead to axial elongation, while the middle and longer wavelengths induced small but significant changes in presence of the hyperopic defocus indicating the potential role of chromatic cues on ocular growth and myopiogenesis. Given that short-term exposure to different wavelengths of light did not induce any asthenopic symptoms, the impact of such specific wavelength exposure on children and its application in myopia control warrants further investigations.
This is a 2021 ARVO Annual Meeting abstract.