A number of analytical formulas have been proposed for the MTF or PSF (Artal & Navarro, 1994; Deeley, Drasdo, & Charman, 1991; Geisler, 1984; Guirao et al., 1999; IJspeert, van den Berg, & Spekreijse, 1993; Jennings & Charman, 1997; Krueger & Moser, 1973; Navarro, Artal, & Williams, 1993; Williams, Brainard, McMahon, & Navarro, 1994). Of these, only two provide formulas for various pupils and white light (Deeley et al., 1991; IJspeert et al., 1993).