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Sayantan Biswas, Muralidharan Arumugam Ramachandran, Veluchamy A Barathi, Wan Yu Shermaine Low, Joanna Fianza Busoy, Dan Milea, Noel A Brennan, Raymond Najjar; The drive for myopia control: interactions between bright light and optical refocus. Invest. Ophthalmol. Vis. Sci. 2021;62(8):1339.
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© ARVO (1962-2015); The Authors (2016-present)
To evaluate the synergetic impact of bright light (BL) and optical refocus (RF) on myopia development in a chicken model of lens induced myopia (LIM).
One day old chicks (Golden Comet/White Leghorn) were assigned to 7 groups of 13 chicks each. Chicks were housed for 7 days in a temperature-controlled enclosure under a 12/12h light-dark cycle (150 lux). Myopia was induced randomly in one eye from the day of hatching (BSL) until day 7 post-hatching (D7) using -10D lenses. The fellow eye was used as uncovered control. Six groups were exposed every day to continuous 4 hours (h) or 6h of either BL (15,000 lux); RF (removal of -10D lens); or both (BL+RF). One group served as control without BL or RF interventions. On BSL and D7, ocular axial length (AL), refractive status and choroid thickness were measured using ultrasonography, infra-red refractometry and optical coherence tomography, respectively. Outcome measures were expressed as the difference between the experimental and control eyes in each animal, and compared between groups and across days using a 2-way repeated measures ANOVA.
By D7, LIM led to significant increases in AL (0.36±0.15 mm) and myopic refraction (-8.51±1.35 D), as well as choroid thinning (-62.1±61.1 µm) in the control group (all, P<0.001). Both 4h and 6h of BL or RF reduced axial elongation and myopic refraction induced by LIM (Fig. 1) while only 6h of BL or RF prevented choroid thinning (Fig. 1F; P<0.05). RF was more effective than BL in preventing axial elongation and myopic refraction development (Fig 1). BL+RF (4h) was less effective in slowing LIM compared to RF (P=0.04; Fig. 1B), while 6h of BL+RF stopped axial elongation, refractive error development and choroid thinning induced by LIM, compared to BL (P<0.001) and RF (P=0.03).
Daily exposure to 4 or 6 hours of BL or RF slows LIM in chickens. Combined with RF, only 6h of BL can stop LIM. The synergetic effect of BL and RF is dependent on the duration of the intervention.
This is a 2021 ARVO Annual Meeting abstract.
Fig. 1. Changes in AL, refraction and choroid thickness (expressed as LIM eye – control eye) in groups exposed to 4h (A, B, C) or 6h (D, E, F) of BL, RF or both (BL+RF). All groups are significantly different from the LIM group (P<0.05) # or from each other (P<0.05) ‡. *: P<0.05.
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