A large, backlit digital display is helpful for people with poor eyesight. Backlit displays shine light from behind the numbers, making them easier to read in the dark. You’ll also want to look for a clock with large control buttons. With big buttons, you won’t need to squint to see what you’re doing. You may also want to consider an alarm clock that projects onto the wall. The projected numbers will be larger than the display, making it even easier to read.