The teaching-Kirk-about-the-glasses thing is like the bit in "Shore Leave" when Sulu somehow thinks it necessary to explain how a gun works. "It fires lead pellets propelled by expanding gases from a chemical explosion." It's bad writing -- a cheap way of saying "Hey, this is the future!"
Does a modern archery hobbyist have to explain how the flexible bow stores potential energy, which becomes kinetic energy propelling the arrow forward when the bowstring is released?
EDIT: After reading some of the preceding posts, I do see how Kirk might possibly be a bit unsure about how to use the antique-style half-spectacles.
A beaker full of death wrote:
... Shatner ceases to wear the wig, etc...
Wouldn't happen - Shatner did doff the wig for The Deadly Years, but he's very self-conscious about his hair.
They'll take Shatner's toup when they pry it from his cold, dead scalp!