Topogon lens

Topogon lens

[′täp·ə‚gän ¦lenz]
(optics)
A periscopic lens with supplementary thick menisci to permit the correction of aperture aberrations for a moderate aperture and a large field; one or two plane-parallel plates are sometimes added to correct distortion.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.