Red-free filter | definition of red-free filter by Medical dictionary
red-free filter Gynecology A green or blue filter used in colposcopy, which ↑ contrast between blood vessels and background, improving evaluation of superficial vessels. See Colposcopy.
McGraw-Hill Concise Dictionary of Modern Medicine. © 2002 by The McGraw-Hill Companies, Inc.
References in periodicals archive
This machine has an ultra-widefield lens, alongside a red-free filter
, which means that more of the peripheral part of the fundus can be seen.
* The red-free filter
(green light) can be used to visually enhance lost nerve fibre bundles in glaucoma, or to give greater contrast to haemorrhages and the retinal vasculature
Choroidal naevus: Mildly elevated lesion with a feathery margin and consistent pigmentation, which disappears with a red-free filter