effectivePupilArea computes the effective area of the illuminated pupil from its diameter.
diameter in mm
Pupil effective area in mm^2
#Smith, VC, Pokorny, J, and Yeh, T: The Farnsworth-Munsell 100-hue test in cone excitation space. Documenta Ophthalmologica Proceedings Series 56:281-291, 1993.
# Pupil area in mm^2 for diameter = 2 mm ## Not run: effectivePupilArea(2)