These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Functional characteristics of blue-on-yellow perimetric thresholds in glaucoma.
    Author: Felius J, de Jong LA, van den Berg TJ, Greve EL.
    Journal: Invest Ophthalmol Vis Sci; 1995 Jul; 36(8):1665-74. PubMed ID: 7601646.
    Abstract:
    PURPOSE: Blue-on-yellow (B-on-Y) perimetry assesses the S-cone visual field under yellow adaptation. Glaucomatous field defects have been shown to appear earlier and to be larger in B-on-Y perimetry than in standard perimetry. An upper limit to the use of B-on-Y perimetry is set by the separation of the S-cones from the M- and L-cones. But, because the S-cones may also input to the luminance channel, the actual separation of the color and luminance channels is unknown. Here, the relative sensitivities of the color and luminance channels under B-on-Y test conditions are measured. METHODS: In 15 eyes with early glaucoma, 19 risk eyes, and 10 normal eyes, B-on-Y thresholds were measured from 0 degrees to 20 degrees eccentric and were compared to pure chromatic (B-in-Y) and achromatic (Y-on-Y) thresholds, obtained under identical yellow adaptation. RESULTS: In normals, B-on-Y thresholds were found to coincide with B-in-Y thresholds; Y-on-Y values were 0.5 log (at 20 degrees) to 0.9 log (at 0 degrees) higher. In the pathologic groups, the differences between B-in-Y and Y-on-Y thresholds were smaller. Pathologic threshold elevation is on average 1.8 times larger for chromatic than for achromatic stimuli. In some cases, the luminance channel takes over detection of the B-on-Y stimulus. CONCLUSIONS: In normals, the B-on-Y stimulus is mediated by the color channel. Takeover of detection by the luminance channel might impose limits on following color defects with B-on-Y perimetry. This takeover may occur before the S-cones become less sensitive than the M- and L-cones and might indicate S-cone input to the luminance channel.
    [Abstract] [Full Text] [Related] [New Search]