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Message: <blockquote data-quote="Binastro" data-source="post: 3631961" data-attributes="member: 111403">Post 18.This morning after 4 1/2 hours I awoke in a dark room.My eyes were dark adapted and there was faint light illuminating the bookcase with white and various dark objects.With both eyes open I reckoned that the image was 20% to 30% brighter than with either left or right eye alone.I tried this several times.When younger, at night I think the difference was very clear with two eyes compared to one just looking at the stars and sky background.In the day I doubt that it makes much if any difference, but I am not sure.</blockquote>