The use of "blind" in the title is problematic in several serious ways, not least, for being obviously false for any conventional interpretation. Idle comment:

The use of "blind" in the title is problematic in several serious ways, not least, for being obviously false for any conventional interpretation. Idle comment: were divergent focal point such a significant issue for visual perception, IMO we could anticipate it would be widely applied by evolution, and we would see many prey species hiding inside blue blurs. There are innumerable reasons this is not the case; but that it isn't is one more problem with the conjecture.