Application of the polychromatic defocus transfer function to multifocal lenses

PURPOSE: To model the performance of multifocal lenses in polychromatic lighting. METHODS: The defocus transfer function (DTF) is a mathematical technique for illustrating the optical transfer function for all levels of defocus at a given wavelength. A polychromatic version of the DTF is developed that accounts for changes in cutoff frequency, reduction in diffraction efficiency, ocular chromatic aberration, and photoreceptor spectral sensitivity. The differences between the monochromatic and polychromatic DTF are illustrated with a diffractive multifocal intraocular lens. RESULTS: Polychromatic analysis shows an increase in depth of field of diffractive lenses relative to assessment at a single wavelength. CONCLUSIONS: The polychromatic DTF is a useful tool for analyzing presbyopia treatments under "white-light" viewing conditions and provides feedback to lens designers on anticipated performance.