[plusone]

That is my point. Blind people still have eyes, yet because of some little misconnection, they are left blind. The whole system must work perfectly to be of any use. What good is a 'proto-eye'? If it doesn't work, then it doesn't give the holder any advantage over his rivals.

[general_re]

The one-eyed man doesn't have a fully functioning vision system either - why is he king in the land of the blind?

[Dimensio]

What good is a 'proto-eye'? Well, a creature with a sensory organ that can detect between different light levels will do better than one that cannot detect such things at all.

The whole 'eye' argument is beyond buried. There are examples of 'partial' eyes if you bother to look.