What power did Superman lose when he went from the silver Superman to the modern era Superman?

The silver era ( say sixties) superman seemed to separate heat vision and x-ray vision as separately controlled powers, he also used telescopic vision. possibly one or more of these powers has been combined. Apart from 48-hour crises from unpredictable Red Kryptonite, Superman has never had ( power crises) common to some other superheroes such as Green Lantern, who even seemed to have spiritual energy slumps and much problems in concealing his power lantern.