Here is a sentence from Frankenstein; or, The Modern Prometheus (the beginning of Letter 2):
How slowly the time passes here, encompassed as I am by frost and snow!
Here is the full text: http://www.gutenberg.org/files/84/84-h/84-h.htm
At the time the character writes the sentence, he is in the northern part of Russia, in the city of Archangel (Arkhangelsk), from which he plans to go on an expedition to the North Pole.
OALD says that as used in such a way (with an adjective in front of it) is synonymous with though. But looking at the context, I don't think though is really what the author meant.
In a Russian translation of the book, this sentence sounds like:
How slowly the time passes for those who are encompassed by frost and snow!
What does encompassed as I am actually mean? Is it equal to though I am encompassed, or is it just a kind of inversion, with the "direct" version being as I am encompassed and the as meaning while (i.e. during the time) or something like that?
- How slowly the time passes here, though I am encompassed by frost and snow!
- How slowly the time passes here, while I am encompassed by frost and snow!