In order for you to see something, your brain has to interpret it by receiving the signal from the light. That's why the light travels into your eye through many parts. Once it passes the cornea, it then goes to your lens. After that, it goes to your pupil, then into your nerve system. Of course, your nerve system is connected to your brain. So that's when your brain is able to receive the signal and then interpret. It's not as simple as it sounds, but it happens very quickly. You don't really feel the light going through all this process.