if you syill have friends at the library
order some of these articles
"Marjorie L. Moorefield" wrote:
> I'm back to seeing things in Black and White again.
> No color all last evening nor today, but this evening
> the color is coming back.
Neurology 1992 Apr;42(4):887-90
Abnormalities in color vision and contrast sensitivity in
Parkinson's disease.
Price MJ, Feldman RG, Adelberg D, Kayne H
Department of Ophthalmology, School of Public Health,
Boston
University School of Medicine, MA.
Dopamine is a neurotransmitter found in the retina.
Delays in the visual
evoked responses and abnormalities in contrast
sensitivity occur in
patients with Parkinson's disease. Improvement in the
P100 has
followed L-dopa therapy. Suspected abnormalities at the
retinal level in
Parkinson's disease are observed in reductions in
photopic, scotopic,
and pattern-derived electroretinograms. We studied 35
patients with
Parkinson's disease and 26 controls of comparable age and
visual
acuities using visual evoked responses, color vision, and
contrast
sensitivity testing. Contrast sensitivity thresholds were
significantly
different at most frequencies tested, using both
stationary and
temporally modulated sinusoidal gratings. The total error
score of the
Farnsworth-Munsell 100 Hue Test revealed significant
differences
between the patients and controls. The contrast
thresholds derived
from certain spatial frequencies and the total error in
color score were
significantly related to the duration of disease. A
stepwise discriminant
analysis correctly identified 94% of the patients and 94%
of the controls.
The significant error in chromatic discrimination
observed in Parkinson's
disease patients may be due to altered intraretinal
dopaminergic
synaptic activity in these patients.
PMID: 1565248, UI: 92228188
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Ray Strand
...on the edge of the prairie abyss ......................
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48/47 dx/40 ? onset pd
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