halo
[ha´lo] a circular structure, such as a luminous circle seen surrounding an object or light.
Fick's halo a colored circle appearing around a light, experienced by wearers of contact lenses.
halo glaucomato´sus (glaucomatous halo) a narrow light zone surrounding the optic disk in glaucoma.
senile halo a zone of variable width around the optic disk, due to exposure of various elements of the choroid as a result of senile atrophy of the pigmented epithelium.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.
ha·lo
(hā'lō), 1. A reddish yellow ring surrounding the optic disc, due to a widening of the scleral ring making the deeper structures visible.
2. An anular flare of light surrounding a luminous body or a depigmented ring around a mole.
4. A circular metal band used in a halo cast or halo brace, attached to the skull with pins.
[G. halōs, threshing floor on which oxen trod a circle; the halo round the sun or moon]
Farlex Partner Medical Dictionary © Farlex 2012
ha·lo
(hā'lō) 1. A reddish yellow ring surrounding the optic disc, due to a widening of the scleral ring making the deeper structures visible.
2. An anular flare of light surrounding a luminous body or a depigmented ring around a mole.
See:
halo nevus 4. A circular metal band used in a halo cast or halo brace, attached to the skull with pins.
[G. halōs, threshing floor on which oxen trod a circle; the halo round the sun or moon]
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
halo
A coloured ring of light seen around a light source as a result of aberrations, internal reflections, diffraction or scattering. It also appears when the eye is diseased and the cornea is oedematous, as in glaucoma.
Millodot: Dictionary of Optometry and Visual Science, 7th edition. © 2009 Butterworth-Heinemann