The Bible says, "The eye is the lamp of the body; so then if your eye is clear, your whole body will be full of light. "But if your eye is bad, your whole body will be full of darkness. If then the light that is in you is darkness, how great is the darkness (Matt 6:22-23 NASU)!
The light that the world uses to see, which is the sun, will blind you if you look at it directly. The light that the Christians use, which is Jesus, will illuminate their lives when looked directly into.