halo

1. A reddish yellow ring surrounding the optic disk, due to a widening of the scleral ring making the deeper structures visible. 2. An annular flare of light surrounding a luminous body or a depigmented ring around a mole. See h. nevus. 3. SYN: areola (4). 4. A circular metal band used in a h. cast or h. brace, attached to the skull with pins. [G. halos, threshing floor on which oxen trod a circle; the h. round the sun or moon]

- anemic h. pale, relatively avascular areas in the skin seen around vascular spiders, cherry angiomas, and sometimes in acute macular eruptions.

- glaucomatous h. 1. a yellowish white ring surrounding the optic disk, indicating atrophy of the choroid in glaucoma; SYN: glaucomatous ring. 2. a h. surrounding lights, caused by corneal edema in glaucoma. SYN: rainbow symptom.

- senile h. circumpapillary h. seen in choroidal atrophy of the aged.

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Halotestin

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ha·lo 'hā-(.)lō n, pl halos or haloes

1) a circle of light appearing to surround a luminous body esp one seen as the result of the presence of glaucoma

2) a differentiated zone surrounding a central object <the \halo around a boil>

3) the aura of glory, veneration, or sentiment surrounding an idealized person or thing

4) an orthopedic device used to immobilize the head and neck (as to treat fracture of neck vertebrae) that consists of a metal band placed around the head and fastened to the skull usu. with metal pins and that is attached by extensions to an inflexible vest called also halo brace

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ha·lo (haґlo) [L., from Gr. halōs disk of the sun or moon] 1. a luminous or colored circle, such as the colored circle seen around a light in glaucoma. 2. a ring seen around the macula luteae in ophthalmoscopical examination. 3. the imprint of the ciliary processes upon the vitreous body. 4. a metal or plastic band that encircles the head or neck, providing support and stability as part of a halo device.