Fig. 3.

Effects of flickering light emitted from white LEDs on choroidal thickness over the day. With 400 Hz flicker at 20 lx (green; seen as continuous light by the chicks), the choroid became rapidly thinner over the first few hours but then remained constant. When 20 lx light was flickered, the choroid became thicker both at 1 Hz (blue) and 10 Hz (red) but did not reach the thickness that was developed under brighter laboratory lighting (470 lx, yellow line) (n = 6 chickens at 1 Hz, 10 Hz, and 400 Hz respectively; n = 8 chickens under laboratory lighting). The blue and yellow bars in the bottom denote diurnal dark and light cycles. Colors of the asteriks match the colors of the interrupted lines denoting which data were compared. Two-way repeated measures ANOVA with Tukey–Kramer post hoc test;*p < 0.05, **p < 0.01