Just to clarify my earlier comment re my class 1. My eyesight was right on the limit when I went for my initial at age 29. One eye under, the other slightly over - nothing unusual, just simple short-sightedness. I saw the top optician at Gatwick (in fact I think he was a eye surgeon) and yes age did come into it.
If I'd had that prescription in my late teens, then he would have known that it would have got worse in middle age. But at 29 he knew my eyesight had settled down and was happy to pass me. In fact the limits are more generous now and I wouldn't have any trouble passing an intial on eyesight.
The point I was making is, don't give up if there's half a chance. Some things are cut and dried like colour blindness, but others not so.