Two Short Lecture:
(1). Properties of the Retina
(2). Properties of V1 and the Ventral Stream. 
Read 1.3 from Yuille and Kersten. 
This is a very brief introduction to extremely complex topics. Your can read much more about mathematical models of photoreceptors in the handout by Bialek and about the retina in the handout by Gollisch and Meister. The handout by Whitney and Levi describes visual crowding which is one of the more surprising aspects of the early visual system. The handout on Mike Mays gives some insight into what happens if you recover you sight after many years of blindness. Clay Reid’s lecture gives a very good introduction to the neuroscience of the brain.
Zhaoping Li’s book gives detailed mathematical models of how the retina could encode input signals for transmission to the visual cortex.