HT1272 - Harder than I Thought, Reason 2

When I spend the morning and even into the afternoon working on my computer at close distance, I find that my eyes tire and don't serve me as well in the late afternoon. I don't have that problem if I spend the morning out photographing because I'm not locking my eyes into one focus distance. This is a function of age, I'm sure, but it's a reality that I need to deal with as a complication now that I'm approaching 70.