Distometer Set Complete
The Distometer is designed to measure the distance between the cornea and spectacle or trial lenses (vertex distance). A change in vertex distance results in a change in the effective power of the lens. This becomes especially sensitive above plus or minus five diopters. A conversion scale is supplied with each distometer instrument, which allows you to quickly and accurately calculate the new correction necessary in the spectacle lens, to obtain the same visual acuity as was achieved with the trial lens.
Please also see alternate Distometer.