Given the task definition and input, reply with output. In this task, you are given a paragraph, and your job is to generate comma-separated entities present in the given paragraph. Generate entities from a given passage in such a way that (i) they are present in the paragraph, (ii) they are non-duplicate, (iii) they underwent a state change during the process. Avoid creating entities that (i) aren't present in the process paragraph and (ii) aren't significant. 

The cornea and lens refract light into a small image. Shine it on the retina. The retina's rods and cones convert it to electrical pulses. The optic nerve carries electrical pulses through the optic canal. Nerve fibers end in the lateral geniculate nucleus and the visual cortex. 

light ,small image ,retina's rods and cones ,electrical pulses 