And why do some operators insist on turning the cabin lights to either dim or off just before take off and landing at night? It can't seriously be for night adapation of the passenger's eyes as no way can you be night adapted in just a few minutes.
In any case reading lights are allowed on, so it's not night adaption. Problem is with lights turned low or off, you can't see where the emergency exists are, especially for older people with eye sight limitations. The pilots have their landing lights on for take off and landing, so obviously they are not worried about night adaption - so why are the hapless passengers stuck with it?
Sounds like its a myth from the days when wartime night fighter pilots wore dark goggles for night adapation while on standby.