This simulation below is why for someone with high myopia like me is not advisable to go outside without glasses. I was walking along a road that is being closed for traffic, and cleaning up my glasses when I heard my friend yelled at me.
“Watch out for the branches”
By reflex I look up, and squint while cleaning up my glasses.
“Where”, I asked her. “I don’t see anything.” “Put on your glasses,” she replied. I follow her advise, and immediately understand what my friend was talking about.
So, yeah, walking without glasses is not advisable for someone who need -12 correction. At least, not where the road is full of dirt and garbage