Our sun eminates electromagnetic radiation over an enormous range of frequencies. Radiation curves (energy@wavelength) resemble bell curves, and highly accurate measurements have shown that the peak of the sun's radiation curve is in the visible light range. This is not a coincidence, it is exactly what we would expect according to the Theory of Evolution. This observation explains why visible light was chosen from the broad spectrum of EM frequencies. But there is another equally compelling reason that we "chose" visible light, and that is where we find our coincidence: Water is transparent to visible light. All life on earth is surrounded by water in either liquid or vapor form. Having vision in the microwave or radio spectrum (on earth) would mean that everything would be about as clear as antartica on a bad day (when the water goes opaque for us). We could use this coincidence to asses the likelihood of intelligent life on other planets in the galaxy (Max output of the star corresponds to a spectrum for which the planets main enviroments are transparent. I don't know if we can tell what gases are present on distant planets.) It is arguable that intelligent life could exist without vision, but I think that the universe is too brutal for it to evolve to an intelligent stage. It is also concievable that humans could have evolved vision in the visible range even if it was not the peak of the suns spectral curve. My apologies if these ideas are considered basic, I have never thought much about astrobiology before.