Something else for consideration, is whether or not someone is dependent on glasses. My vision is absolutely terrible without glasses, and if something should happen in the middle of the night that might require a firearm to fix, I can't be absolutely sure that I'll have the time to grab them. Because of this I regularly practice shooting without my glasses, both "target" and "combat" style shooting.
Even disregarding the "bump in the night" scenario, every fight I've ever been in has left me fighting without glasses on since they tend to be the first thing that goes missing in such an event. If I should ever need to draw to defend myself, I want some confidence in my chances even if I've lost my glasses.
For those with good natural eyesight, you could always buy some cheap glasses and start practicing with blurry drunk vision
---Perfection is achieved, not when there is nothing more to add, but when there is nothing left to take away.---
---Enlightenment is the ability to take infinite pains---