The eyeglasses scene doesn't make sense.
I can buy Kirk questioning their presence in his 23rd century (where vision problems don't require mechanical eyewear).
I can buy the fact that eyeglasses are a rare sight in everyday life in Kirk's time.
But I don't buy Kirk needing McCoy to explain how they function
. Certainly Kirk is vaguely familiar with photos of people from history, and there are millions of such photos of people wearing eyeglasses. Kirk should know what those things are, how they were worn. It shouldn't be a mindboggler for Kirk.