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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.
1. a yellowish white ring surrounding the optic disc, indicating atrophy of the choroid in glaucoma; Synonym(s): glaucomatous ring
2. a halo surrounding lights, caused by corneal edema in glaucoma. Synonym(s): rainbow symptom
glau·co·ma·tous ha·lo(glaw-kō'mă-tŭs hā'lō)
1. A yellowish white ring surrounding the optic disc, indicating atrophy of the choroid in glaucoma.
2. A halo surrounding lights, caused by corneal edema in closed-angle granule closure glaucoma.