oh happened to see your comment and a friend of my adult child I met a few years ago kept moving his eyeglasses and sort of squinting etc. and I remember him saying he has to keep adjusting his glassses because of such and. such problem - not sure would help your Grampa but will ask him about it if I can on facebook as he is still far away friend of family.... does seem odd that his (your Grampa) can see ok for short time - I wonder why too! Best of luck on here...