Can not wearing of glasses with defect shortsightedness and astigmatism of person over 50 years of age lead to visual impairment ?
What does it depend?

It is true that eyesight like other functions does deteriorate with age and eyesight should be checked regularly with an optician. This is also useful for spotting the first signs of age related macular degeneration and other disease of the eye that can lead to blindness. Raised intra ocular pressure that is a sign of glaucoma is also something that can be picked up.

There really is no excuse for skipping eye checks, taking the risk of blindness is simply foolish.