Because the main cause of cataract is simply ageing, given that we are all living longer lives than our predecessors the incidence of cataract continues to rise.  Essentially cataract means that the lens inside the eye is becoming cloudy, anywhere from a little bit cloudy to very cloudy.  Cataract is not a film that grows across the front of the eye.  Having cataract does not mean you are going blind.  Cataract is a very normal change, especially from the 60s and 70s and beyond.  The good news is that cataract surgeons have improved their skills and procedures to the point where having cataracts removed is almost a routine operation.