Thank you, Tony, for knowing the melanopsin work. I misremembered it as a hormonal signaling pathway -- though it will affect one later -- but am glad that i remembered properly that eventhose who wind up w destroyed optic nerves still would have the light register for effects but not for perception due to not using the optic nerve neural pathway. The ultimate answer for Nell is that the type of blindness would completely matter so the assumption can not be made. [Posted in FML 7516]