Abstract

As part of a study of the relationship between the optical quality of low-vision aids and the quality of vision provided by these devices we wanted to measure their modulation transfer functions (MTF). We present our apparatus for measuring the MTF of low-power telescopes and telemicroscopes (instruments that are nominally afocal in image space). We can test at spatial frequencies up to 100 cycles/deg in object space. MTF tests may be made across the field of vision, through focus, at 0°, 45°, 90°, and 135° scan azimuths, with white light or passband filters, and with artificial pupils. A computerized data acquisition and analysis system corrects digital data for noise, and computes and plots the MTF curves. MTFs of some commonly prescribed telescopic aids are shown and compared.

© 1985 Optical Society of America