Lawton T B
Jet Propulsion Laboratory, California Institute of Technology, Pasadena 91109.
Ophthalmic Physiol Opt. 1992 Apr;12(2):193-200. doi: 10.1111/j.1475-1313.1992.tb00289.x.
As people age, so do their photoreceptors; many photoreceptors in central vision stop functioning when a person reaches their late sixties or early seventies. Low vision observers with losses in central vision, those with age-related maculopathies, were studied. Low vision observers no longer see high spatial frequencies, being unable to resolve fine edge detail. We developed image enhancement filters to compensate for the low vision observer's losses in contrast sensitivity to intermediate and high spatial frequencies. The filters work by boosting the amplitude of the less visible intermediate spatial frequencies. The lower spatial frequencies. These image enhancement filters not only reduce the magnification needed for reading by up to 70%, but they also increase the observer's reading speed by 2-4 times. A summary of this research is presented.