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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