I love Ibn Sina's and Aristotle's ideas and thoughts toward light and illumination. It's amazing how much information they were able to get with so little technology and available knowledge.

The idea of extramission and intromission are both great theorys for vision although the idea of extramission has been much more popular in history.
Plato describes color to be the mixing in air of two beams of fire, one from the the eyes and one form the object being viewed. Aristotle, like many of Plato's theorys, disagreed and thought that color was carried in only one direction - light reflecting off of objects.

The idea of sight and color and how we're able to see things has always and always will be a huge discussion in history.