@doonxib It's not guided. You should read a standard textbook about the evolution of the eye. There are surviving species with examples of every major stage of its development, starting with a light sensitive spot and ending with the paragon of visual perception, stereoscopic lensed color.

Each step increases useful sensory data.

As to not knowing how it works at birth, why would you? Evolution takes place on a timescale beyond a human lifespan, at least at the level where there's something we might respond to. The brain needs to dedicate ROM to language processing and pattern recognition. No room for a scientific encyclopedia.