[Cartographic errors in perimetry]. / Der kartographische Fehler in der Perimetrie.
Klin Monbl Augenheilkd
; 198(2): 108-11, 1991 Feb.
Article
in De
| MEDLINE
| ID: mdl-2041363
ABSTRACT
Cartography in perimetry repeats the problem of the cartography of the globe it is impossible to transfer the image properly without a distortion of either angles, distances or areas. The projection type mostly used in perimetry leads to an enlargement and a tangential deformation that increases overproportionally towards the periphery (30 degrees +5%, 60 degrees +20%, 90 degrees +57%). A circular scotoma, for example, is charted as en ellipse. In the opposite case, when a test point pattern is transferred from the perimetric chart to a perimetric sphere, there is a deformation, too. The distances between the test points are reduced in tangential direction, compared to the chart. A test grid with equidistant points on the chart appears in a rhomboid or rectangular distortion. This phenomenon has to be considered in the design of test point patterns for automatic static perimeters.
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Collection:
01-internacional
Database:
MEDLINE
Main subject:
Scotoma
/
Computer Graphics
/
Signal Processing, Computer-Assisted
/
Visual Field Tests
Limits:
Humans
Language:
De
Journal:
Klin Monbl Augenheilkd
Year:
1991
Document type:
Article