Apart from the importance of light for visualization and making objectives and images of things to be seen. Light itself is involved in the very production of living organisms, plants and animals, through what is known as “photosynthesis” where water, carbon dioxide and nutrients are fundamental raw materials. This is in addition of being essential for the production of electricity by modern solar panels through what is known as the “photo-electric effect” originally explaied by Einstein.

http://en.m.wikipedia.org/wiki/Illustration