Figure 2.
Irradiance response curves for ‘steady state pupil size’ in young and old mice. (A) Consensual pupil constrictions to white light demonstrated a shift in sensitivity between young (n=8) and old mice (n=8). Following curve fit analysis (A) the LogEC50 was greater in the aged group (p<0.05); thus, aged animals show an overall decrease in sensitivity to light relative to their younger counterparts. Representative pupil images (B) show stable dark-adapted pupil sizes in both young and aged animals, with decreasing pupil areas when exposed to intermediate (Log10 photons/cm2/s) and bright (Log14 photons/cm2/s) irradiances.