Abstract
The disagreement between physical and psychophysical estimates of human optical performance is discussed. Recent measurements of the eye's modulation transfer functions in white light for several pupil sizes are used to compare the eye with an ideal optical system in terms of normalized modulation transfer functions, point image profiles, and Strehl ratios. Several simple fundal-image profiles are derived from the measured modulation transfer functions, and the importance of these importance of these profiles to psychophysical measurements is discussed. Glare is considered as the extension of point spread functions to large angles: experimental measurements are compared with theories for the special case of an annular target.