Abstract
Purpose :
To evaluate the impact of broad spectrum, high correlated color temperature (CCT), light emitting diodes (LEDs) mimicking sunlight on ocular growth and refractive error development in a chicken model of myopia.
Methods :
A total of 27, 1-day old chicks (Lohmann Brown) were randomly assigned into 2 groups. Animals were housed for 28 days in a light-tight enclosure, under a 12/12h light/dark cycle of isoluminant (~285 Lux) fluorescent [n = 18, FL, 4000K] or SunLike LED [n = 9, SL, 6900K] white lights. Myopia was induced monocularly in all chicks by random occlusion of one eye with a frosted diffuser from day 1 post-hatching (D1) until D14. At D14, diffusers were removed and chicks were monitored for recovery from myopia under both light conditions. Axial length (AxL), choroid thickness and refractive status, were respectively recorded using ultrasonography, posterior segment optical coherence tomography and infra-red refractometry on D1, 7, 14, 22 and 28. Outcome measures were compared between eyes and groups using a 2-way repeated measures ANOVA.
Results :
AxL and myopic refraction increased in the form deprived (FDEP) eyes of both groups compared to control (CTR) eyes (D7 and D14, P<0.001). FDEP eyes of animals raised under SL had shorter AxL and displayed a faster recovery from aberrant axial elongation compared to animals raised under FL on D22 and 28 (Fig. 1). Correspondingly, only the FDEP eyes of animals raised under SL, recovered to a similar refractive status as CTR eyes by D28. There was no significant difference between FDEP eyes of both groups in either AxL or refraction on D1, 7 and 14. A significant thickening of the choroid was observed on D22 and 28 in the FDEP eyes compared to CTR eyes, under both light conditions. Choroid thickening was significantly higher on D22 in the SL group (515.6±23.9 µm) compared to the FL group (428.4±123.8 µm) (P=0.01).
Conclusions :
Our preliminary results suggest that compared to fluorescent light, moderate intensities of broad-spectrum LEDs of high CCT can accelerate recovery from form-deprivation myopia in chickens, potentially through increasing choroid thickness. Further studies are necessary to evaluate the impact of CCT-matched lights with different spectral distribution on ocular growth and myopia.
This is a 2020 ARVO Annual Meeting abstract.