Re: Something is wrong!!

[John Cottingham <jcott@xxxxxxxxx>]

>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.
>I had this problem after my colon ruptured and I was under
>  so long during surgery. I didn't see any colors for
>several months after that surgery.
>  But I haven't had surgery and
>I haven't been sick.  Well, if you can call having PD NOT being
>sick.
>
>

Marjorie, this might be the answer.

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 du
 ratio
n 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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John Cottingham