| annular scleritis | An often protracted inflammation of the anterior portion of the sclera, forming a ring around the corneoscleral limbus. (05 Mar 2000) |
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| annular sphincter | A short thickening of circular muscular fibres, similar to a ring; a ring-shaped sphincter as opposed to a segmental sphincter. (05 Mar 2000) |
| annular staphyloma | A staphyloma extending around the periphery of the cornea. (05 Mar 2000) |
| annular stop | <microscopy> The opaque ring-shaped stop with a small central opening usually placed in the objective back focal plane to provide dispersion staining. (05 Aug 1998) |
| annular stricture | A ringlike constriction encircling the wall of a canal. (05 Mar 2000) |
| annular synechia | Adhesion of the entire pupillary margin of the iris to the capsule of the lens. (05 Mar 2000) |
| annular syphilid | Cutaneous lesions of secondary syphilis in which the papules form annular lesions with raised papular borders and clear central portions. (05 Mar 2000) |
| Gerlach's annular tendon | fibrocartilaginous ring of tympanic membrane |
| absolute scotoma | A scotoma in which there is no perception of light. (05 Mar 2000) |
| arcuate scotoma | A scotoma extending from the blind spot and arching into the nasal field following the lines of retinal nerve fibres. (05 Mar 2000) |
| Bjerrum's scotoma | A comet-shaped scotoma, occurring in glaucoma, attached at the temporal end to the blind spot or separated from it by a narrow gap; the defect widens as it extends above and nasally curves around the fixation spot, and then extends downward to end exactly at the nasal horizontal meridian. Synonym: Bjerrum's sign, sickle scotoma. (05 Mar 2000) |
| caecocentral scotoma | A scotoma involving the optic disk area (blind spot) and the papillomacular fibres; there are three forms: 1) the caecocentral defect which extends from the blind spot toward or into the fixation area; 2) angioscotoma; 3) glaucomatous nerve-fibre bundle scotoma, due to involvement of nerve-fibre bundles at the edge of the optic disk. See: Bjerrum's scotoma, Ronne's nasal step. (05 Mar 2000) |
| paracentral scotoma | A scotoma adjacent to the fixation point. (05 Mar 2000) |
| glaucomatous nerve-fibre bundle scotoma | See: caecocentral scotoma. (05 Mar 2000) |
| relative scotoma | A scotoma in which there is visual depression but not complete loss of light perception. (05 Mar 2000) |