It does seem complicated, and as always I am thrilled to have an expert weigh in.
I get daily Medpage emails, I think that's where this article turned up.
Here's an image showing how retinal blood vessels are measured. The blue the ones would be the venules.http://circimaging.ahajournals.org/cont ... .large.jpg
Awesome pic, Cece! I DO think the vascular changes in the fundus are (usually) reflective of systemic vascular changes, which makes the fundus such an awesome thing to study! And you likely remember, I'm a big believer in many of our problems being due to enlarged veins...
If you look closely at the pic you attached, you'll be able to see why we are less likely to be able to judge arteriole "size" than venule size. Do you see the arteriole that goes across 11:30? See how the center (the lumen) looks whitish? That is likely atherosclerosis, which can slow or limit the flow of oxygenated blood. We can't really effectively measure the arterioles without considering the 'true' size of the lumen, which these photos can't reveal, unfortunately. It's much easier to do with veins. I know you all understand the Kellie Monroe Doctrine and if our fluid dynamics are unbalanced, we have to look at venous size and flow, arterial size and flow, and (in the brain) CSF pressure and flow -- otherwise we can freak out if we just look at any one aspect.
In order to help 'figure out' M.S., I had to step away from evaluating the fundi of M.S. patients. Once sheathing occurs, we can't tell what the heck is going on with fluid dynamics. Even symptoms you experience can be discombobulated by demyelination ("is the symptom due to 'X' which is easily corrected, or is it secondary to demyelination"). So I revert to related conditions which do not (yet) show demyelination, then see if these problems may be masked by demyelination. Or worse, do doctors just assume the symptoms are from demyelination, missing the treatable conditions... Does that make any sense?
OK, getting off tangent! Back to work -- thank you for letting me jump in, sort of unannounced!
Special interest in "brain drains" and how they affect numerous conditions, including MS, Ehlers-Danlos, Parkinson's, Alzheimer's, etc. I am a therapeutic optometrist on professional disability with EDS, POTS, CCSVI, mast cell disea