α-opic flux models based on the five fundus photoreceptors for prediction of light-induced melatonin suppression

Light is effective to suppress the melatonin and affects the non-visual responses. The relationship between light conditions and melatonin suppression is significant when designing light environments. Based on the alpha-opic illuminances of five fundus photoreceptors, various previous models are built to fit and predict the experimental melatonin suppression. In this study, we present models based on alpha-opic fluxes, which are products of alpha-opic illuminances and pupil areas, to improve the fitting results of the experimental melatonin suppression. For 30 -and 90-min light exposures, the alpha-opic flux models present higher adjusted R-squared and lower root mean square of error (RMSE) when fitting the experimental melatonin suppression, regardless of pupil dilation or not. The alpha-opic flux models also explain the spectral opponency on melatonin suppression. According to the residuals between predicable and experimental melatonin suppression, the effects of pupil dilation, type of light source, and subject's age are further discussed. The subject's age has little effect on the melatonin suppression. The alpha-opic flux models decrease the fitting residuals under different conditions, improving the applicability of the fitting models on melatonin suppression.