halo /ha·lo/ (ha´lo)
1. a luminous or colored circle, as the colored circle seen around a light in glaucoma.
2. a ring seen around the macula lutea in ophthalmoscopic examinations.
3. the imprint of the ciliary processes on the vitreous body.
4. a metal or plastic band that encircles the head or neck, providing support and stability to an orthosis.
Fick's halo a colored circle appearing around a light due to the wearing of contact lenses.
halo glaucomato´sus , glaucomatous halo peripapillary atrophy seen in severe or chronic glaucoma.
senile halo a zone of variable width around the optic papilla, due to exposure of various elements of the choroid as a result of senile atrophy of the pigmented epithelium.
ha·lo (h  l )n. pl. ha·los or ha·loes 1. A reddish yellow ring surrounding the optic disk, caused by an expansion of the scleral ring that makes the deeper structures visible. 2. Glaucomatous halo. 3. A ring of light surrounding a luminous body. |
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.
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