| Discriminating colors through a red filter by protanopes and colour normals. | |
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MedLine Citation:
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PMID: 20444111 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Individuals with color vision deficiency have difficulties in differentiating colour in their daily activities. Through certain coloured filters, dichromats may report an improvement of their capacity to differentiate colors, but it is not known if this is achieved by means of a chromatic mechanism. The present study attempts to explain the mechanism by which a coloured filter can produce a beneficial effect in dichromatic visual perception and what is the nature of this improvement. Four male protanopes and four normal trichromats (two males and two females) participated in the present study. We evaluated the effect of the red filter (with a spectral transmittance similar to that of the X-Chrom filter) on the detection thresholds for monochromatic light stimuli from 420 to 660 nm in 20 nm steps. The increment spectral sensitivity functions were measured for 1.2 degrees diameter test flashes presented for 300 ms on a 60-cd m(-2) illuminant C background using an optical bench with a monochromator, for both filter and no filter conditions. The capacity to correctly name green, yellow and red for the monochromatic lights of 550, 575 and 625 nm presented for 300 ms on a 60 cd m(-2) illuminant C background screen was also evaluated with and without the red filter. The spectral sensitivity data suggest that, the use of a red filter improves the protanope's capacity to detect long wavelength light stimuli. The results on the colors naming procedure demonstrate that the red filter modifies colour perception in normal and protanope subjects. In normals, only the red color perception is preserved, and typical colour perception for the green and the yellow is lost. Without the filter, all the protanopes demonstrated a residual colour perception for red and green colours. Through the red filter only red colour perception remains. A red filter does not improve the protanopic red-green perception, but it does improve the ability of the protanope to detect long-wavelength light. This improvement seems to arise by means of the luminance mechanism. |
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Authors:
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Vasile Diaconu; David Sullivan; Jean F Bouchard; Valentina Vucea |
Publication Detail:
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Type: Journal Article |
Journal Detail:
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Title: Ophthalmic & physiological optics : the journal of the British College of Ophthalmic Opticians (Optometrists) Volume: 30 ISSN: 1475-1313 ISO Abbreviation: Ophthalmic Physiol Opt Publication Date: 2010 Jan |
Date Detail:
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Created Date: 2010-05-06 Completed Date: 2010-09-03 Revised Date: - |
Medline Journal Info:
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Nlm Unique ID: 8208839 Medline TA: Ophthalmic Physiol Opt Country: England |
Other Details:
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Languages: eng Pagination: 66-75 Citation Subset: IM |
Affiliation:
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School of Optometry, University of Montreal, succursale Centre-Ville, Montreal, Quebec, Canada. vasile.diaconu@umontreal.ca |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Color Perception
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physiology* Color Perception Tests / instrumentation, methods* Color Vision Defects / diagnosis*, physiopathology* Discrimination (Psychology) Female Filtration / methods Humans Male Sensitivity and Specificity Sensory Thresholds |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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