How can I turn down the brightness in my HDTV?

Episode 1083 (2:05:26)

Paul from Orange, CA

Paul has limited vision and wants to know if there's a TV that's friendly to the blind. He wants to be able to Dim the screen because it's too bright to see details. Leo says to change it to Movie Mode in the settings and that will help. His TV is only 42", and Leo advises at least 55" for watching from 10' away.