Short answers, pulled from the story.
Light enters the eye through the cornea and is focused by the lens onto the retina. Specialized photoreceptive cells convert this light into neural impulses that travel via the optic nerve to central ganglia in the brain.
Ibn al-Haytham published Book of Optics around 1021 to reject earlier theories. He demonstrated that vision occurs when reflected light rays enter the eye using systematic experimentation.
The lateral geniculate nucleus sends signals to the primary visual cortex known as striate cortex which divides into ventral and dorsal pathways. The dorsal stream handles spatial awareness functions while the ventral stream manages object recognition tasks.
Hermann von Helmholtz coined unconscious inference in 1867 after examining the human eye. He concluded insufficient retinal data required assumptions based on prior experience such as expecting faces to appear upright.
David Marr developed a multi-level theory of vision during the 1970s identifying three levels: computational, algorithmic, and implementational. His stages include a primal sketch based on feature extraction like edges and regions followed by texture acknowledgment and final construction of a continuous three-dimensional map.