The light you have to have gives off photons which bouse of in different direction before hitting the eye. In order for you to see the tissue it has to go through much be transparent. First it goes through the cornea located at the front of the eye then to the middle of the eye. Next they reach the retina the eyes photographic plate. After the pulses go to the optic nerve. Then it moves into the optic pathways then moves to the opcional brain which creates the image but the image is upside down so our brain flips it which cause us to see the images we see.