Eh? I didn't know that - the quinine in tonic water can cause slightly blurred vision and/or a temporary decrease in COLOR vision (cones; photopic vision) in SOME people (not all), which is why pilots are supposed to abstain from tonic water / quinine for 24 hours before flying, but I never heard or read anything about it affecting scotopic vision - where did you read that?

I like my occasional gin and tonic... or just plain tonic water. But I'll reconsider if it is surely known to adversely affect my night vision.

Regards,

Tom