Originally Posted by
MightyGem
Are you sure, Shy? I wore bi-focals/varifocals for all of my civilian career. My various AMEs never questioned it.
I think you are confusing refractive surgery or lens replacement surgery terminology with eyeglass terminology. If I'm reading things correctly, I think Shy is saying he had lens replacement surgery.
Where refractive or lens replacement surgery is concerned, you can get a single correction or a multifocal correction (
example). The multifocal approach requires the brain to do a lot of "image processing" for lack of a better term. This is, obviously, quite a bit different than a bifocal or varifocal (what us Yanks call "progressive") eyeglass lens.
Since they make multifocal contact lenses (this approach doesn't work in eyeglasses), you can experience the multifocal approach for yourself if you get a pair of multifocal contacts. I tried them and hated it with a passion. I even gave it a good three weeks to get used to them. Couldn't do it. Some people can. Don't know anyone that flies with them, and don't know anyone that has had multifocal refractive surgery, either.