It appears we are thinking along the same lines PAXboy, I can understand an argument for all the above, but Airline professionals will testify to people being refused on the basis of hearing aids, but I would be shocked if even one would say the same for glasses, which must pose at least (if not more in my opinion, as glasses are much more likely to fly off someones head in your perfect example than hearing aid's) threat to safety whilst on an exit seat. Not consistant IMHO, by all means ban them all, but not just one.