The role of temporal contrast and blue light in emmetropization

Abstract

A previous experiment showed that blue light (as a component of white light) protected against low temporal frequency dependent eye growth. This experiment investigated the role of temporal contrast. White leghorn chicks were exposed to white (with blue) or yellow (without blue) LED lighting modulated at either low (0.2Hz) or high (10Hz) temporal frequencies. Four cone contrast conditions were used: low (16%), medium (32%), medium-high (60%) and very-high (80%). Chicks were exposed to the lighting condition for 3days (mean 680lux). Exposure to high temporal frequencies, with very high temporal contrast, reduced eye growth, regardless of spectral content. However, at low temporal frequencies, eye growth was dependent on the illuminant. At lower temporal contrast levels, growth increased regardless of temporal or spectral characteristics. To conclude, very high temporal contrast, white light, provides a "stop" signal for eye growth that overrides temporal cues for growth that manifest in yellow light.

A review on the epidemiology of myopia in school children worldwide

“…Genetic observations add credence to the current notion that myopia is caused by a retina-to-sclera signaling cascade that induces scleral remodeling in response to light stimuli [56]. However, it is possible that other variables may influence emmetropization, including ultraviolet light [57] or blue-light [58]. Moreover, a recent systematic review found that lower blood vitamin D concentrations are associated with increased risk of myopia; on the other hand serum vitamin D levels may be just a proxy for time outdoors [59].…”

Probing the Potency of Artificial Dynamic ON or OFF Stimuli to Inhibit Myopia Development

“…However, it also should be kept in mind that choroidal and scleral growth mechanisms can be partially dissociated with flickered spectral stimuli (i.e., Refs. [31][32][33][34][35][36]. Also, Nickla and Totonelly 37 found that the relationship between choroidal thickening and eye growth inhibition may be disrupted when eye growth was experimentally altered.…”

“…48 In chickens, it was found that 1, 2, and 4 Hz flicker light induced more myopic refractions with deeper anterior and vitreous chambers in the eyes. 49 Rucker and colleagues 35,36 found that the blue light can suppress the effects of flicker light on emmetropization in chickens. Furthermore, they found that dynamic chromatic noise stimulation promotes myopia in chickens, which let the authors conclude that ''emmetropization is further disrupted when randomized color information is combined with randomized luminance information'' (Taylor CP, Rucker FJ.…”

Wavelength Defocus and Temporal Sensitivity Affect Refractive Development in Guinea Pigs

“…At high temporal frequencies, refractions were more hyperopic in yellow light (without blue) than in white light (with blue) in chicks. 39,48 This may be because blue light stimulates the koniocellular color pathway in addition to intrinsically photosensitive retinal ganglion cells. 49 In contrast, at low temporal frequencies, chicks demonstrated a more myopic shift in yellow light compared with white light.…”