Fig. 3 Normal ranges of light reflex amplitude for long and for short flashes. Shaded area (left bracket) is normal range for 3-second flashes; stippled area is normal range for 0.8-second flashes. The numbers above the abscissa indicate the number of subjects per age group. Note early peak, followed by decline with age for reactions to long light flashes. In contrast, reflexes elicited by short flashes show relatively flat age curve. (Reprinted with permission from Loewenfeld IE: Pupillary changes related to age. In: Thompson HS, Daroff RB, Frisen L, et al (eds): Topics in Neuro-Ophthalmology. Baltimore: Williams Wilkins, 1979:137)