I always wear my "Last years" Glasses, expensive plastic Progressive lenses And a Simple glasses retaining strap, have been for 7 years of catsailing, never lost them once, and Rainex works great for most of the day to keep the spots away.
I do However sheet my glases strap in tight before I go out for the day, and if We're gonna capsize, I keep my hand up to keep my glasses "just in case." I usually find it's my hat that gets knocked off or blown off in a capsize.