Figure 1.

An illustration of the pupilogram and the associated PLR parameters. The optical stimulus is given at time zero. The baseline and minimal pupil diameters are calculated as ${\mathrm{D}}_0=2\sqrt{{\mathrm{A}}_0/\pi }\text{ and }{\mathrm{D}}_{\mathrm{m}}=2\sqrt{{\mathrm{A}}_{\mathrm{m}}/\pi }$, respectively. The relative constriction amplitude is obtained as A_% = A₀−A_m /A₀. The constriction and redilation velocities are calculated as v_C=D₀ − D_m /2t_C and v_R= D₀ − D_m /4t_R, respectively.