Abstract

The reduced schematic eye (the "water eye") accurately describes the magnitude of both transverse and longitudinal chromatic aberration of the human eye.¹ The modulation transfer function (MTF) of this model, including the effects of diffraction, is easily calculated for monochromatic light and the results integrated across wavelength to produce a white-light MTF. We investigated how sensitive this MTF is to changes of wavelength-in-focus (i.e., the mean refractive error) and to changes in pupil diameter for a typical (2800 K tungsten) white source. The results indicate that both parameters have significant impact and clear maxima exist. For this source, 570 nm is the optimal wavelength-in-focus for any pupil diameter and a 3-mm pupil is optimal for any wavelength-in-focus. These results are understandable as follows. Although the model is emmetropic for 590 nm, the weight of the luminous efficiency curve shifts the optimal wavelength-in-focus towards shorter wavelengths. The optimal 3-mm pupil balances the tradeoff between the effects of diffraction for small pupils and chromatic blur for large pupils.

© 1990 Optical Society of America