Thank you to everybody who replied to my question regarding "Deteriorating Vision".
Since reading your replies I am not sure if I have Sjogrens Syndrome as I do not have itchy, gritty or inflamed eyes which most people seem to have who suffer from this disease. I feel as though I am looking out of a greasy window and keep wanting to rub my eyes to clear them.
I have needed glasses for reading for some years but the prescription was not high and, as I am waiting to see what is said at the hospital before I spend a lot of money on a new pair, I am having real difficulty with reading, especially in a poor light and have to resort to a magnifying glass sometimes.
I have purchased a new pair of glasses from Glasses Direct for distance, which I have never needed before, because everything was a blur when I was indoors and out and about.
Before Christmas everything was fine - this only came on in late January / early February. I am not sure if this is in any way connected to another auto-immune disease or to PBC. It just seems to me that if it's not one thing it's another.