| Seidel's scotoma | A form of Bjerrum's scotoma. See: Seidel's sign. (05 Mar 2000) |
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| Schweigger-Seidel, Franz | <person> German physiologist, 1834-1871. See: sheath of Schweigger-Seidel. (05 Mar 2000) |
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| Seidel | Erich, German ophthalmologist, 1882-1946. See: Seidel's scotoma, Seidel's sign. (05 Mar 2000) |
| Seidel's sign | <clinical sign> A sickle-shaped scotoma appearing as an upward or downward extension of the blind spot. (05 Mar 2000) |
| sheath of Schweigger-Seidel | <geometry> A solid, all plane sections of which are ellipses or circles. See Conoid, 2 . The ellipsoid has three principal plane sections, a, b, and c, each at right angles to the other two, and each dividing the solid into two equal and symmetrical parts. The lines of meeting of these principal sections are the axes, or principal diameters of the ellipsoid. The point where the three planes meet is the center. Ellipsoid of revolution, a spheroid; a solid figure generated by the revolution of an ellipse about one of its axes. It is called a prolate spheroid, or prolatum, when the ellipse is revolved about the major axis, and an oblate spheroid, or oblatum, when it is revolved about the minor axis. Origin: Ellipse: cf. F. Ellipsoide. Source: Websters Dictionary (01 Mar 1998) |
| absolute scotoma | A scotoma in which there is no perception of light. (05 Mar 2000) |
| annular scotoma | A circular scotoma surrounding the centre of the field of vision. See: ring scotoma. (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) |
| central scotoma | A scotoma involving the fixation point. (05 Mar 2000) |
| mental scotoma | Absence of insight into, or inability to comprehend, items relative to a subject whose content is highly emotional to the individual. Synonym: blind spot. (05 Mar 2000) |
| pericentral scotoma | A scotoma that surrounds the fixation point more or less symmetrically. (05 Mar 2000) |