halo

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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.

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.
3. Synonym(s): areola (4)
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]

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

(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
3. Synonym(s): areola (4) .
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]

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.
References in periodicals archive ?
Parhelion won six times over hurdles for Derek who served his time with the late and great Harry Wragg.
Beaubrav had no trouble following up his recent course win under top weight in the 1m5f handicap, with the fiveyear-old scoring in style by two and a half lengths from Parhelion.
There was also a close call in the following 1m4f handicap with Hel's Angel, ridden by Seb Sanders, holding on by a short head from Parhelion to give trainer Ann Duffield her first winner for 56 days.
Another of Johnston's recent winners, Manxman, will also be going hurdling with Murphy after making pounds 24,000, while Parhelion, who broke his duck in a Wolverhampton maiden last month, will head to Wales after being knocked down to Vaughan for pounds 35,000.
William Hill: 7-2 Alamshar, 5 Brian Boru, 8 Refuse To Bend, 10 Hold That Tiger, 16 Alberto Giacometti, Muqbil, New South Wales, 20 Chevalier, Lateen Sails, 25 Ikhtyar, Powerscourt, Songlark, 33 Almushahar, Bourbonnais, Big Bad Bob, Battle Chant, Graikos, Parhelion, Saturn, Shield, Tomahawk, 40 bar.
Bin Suroor, who also runs Bourbonnais, Anasheed, Parhelion and Songlark, said: "Inamorato won his first race in America over five and a half furlongs, and he won very easily on his first race for me.
lKen White is in treble form at Wolverhampton, beginning with Parhelion (Derek Haydn Jones), who takes the two-and-a-half- mile hurdle from Idro (Ray Peacock/Martin Blackshaw).