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Spatial tuning affects diagnostic efficacy of pseudoisochromatic plates
Author(s) -
KRASTEL H,
KALTAKJI F,
LEERS S,
JERCHEL N,
JONAS JB
Publication year - 2012
Publication title -
acta ophthalmologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.534
H-Index - 87
eISSN - 1755-3768
pISSN - 1755-375X
DOI - 10.1111/j.1755-3768.2012.f064.x
Subject(s) - standard illuminant , viewing angle , luminance , visual angle , computer vision , artificial intelligence , camouflage , optics , mathematics , computer science , optometry , physics , medicine , liquid crystal display
Purpose To demonstrate that the diagnostic efficacy of pseudoisochromatic plates is reduced by oversized and by undersized angles of observation. Methods Pseudoisochromatic “C” and “E” plates accounting for equal demands on color vision in repeated exams were presented to 7 daltonian and 10 normal observers. An illuminant D 65 source (Unity Color Light2go) rendered 170 cd/m2 of luminance. The standard viewing time was 3 s, the viewing angles were 33.4°, 7.4° and 1.8°. Results Daltonians failed to recognize the plates at 7.4° of visual angle which correspondes to the recommended standard viewing distance. At a viewing angle of 33.4° the plates were recognized by 4 of 7 Daltonians. At a viewing angle of 1.8° the plates were recognized by 3 of 7 Daltonians. With 1.8° of viewing angle, normal observers claimed fusion of i) those various pseudoisochromatic picture elements which are on the red side of yellow, and of ii) those various elements which are on the green side. Conclusion A standardized observation distance (0,7 m) is necessary for pseudoisochromatic plates, as recommended by Ishihara and Velhagen. At small viewing angle, antagonistic processing of colored picture elements is impaired, causing loss of optotype camouflage. At large viewing angle, individual elements may activate weak color opponent mechanisms in a daltonian retina where green cones or red cones are scarce but not entirely lacking. Poster visitors may observe spatial tuning within their own color vision.Commercial interest