I joined without glasses (managed to squint through the eye test) .. issues with glasses through training .. progressed to lens after about 5 years.. they were fantastic and neither glasses or lens made any different for the 4000 hrs fast jet I accumulated (apart from the few AR5 trips which were thankfully seldom, but awkward). Had trips in F16 and M2000, no problem under high G.. lens were way better, but I reverted to bifocal glasses after about 20 years as long sight improved .. it's a huge misnomer and a way for recruiters to thin out potentially candidates..!! Just my view..!