"No one lights a lamp and then hides it or puts it under a clay pot. A lamp is put on a lamp stand, so everyone who comes into the home can see the light. Your eyes are the lamp for your body. When your eyes are good, you have all the light you need. But when your eyes are bad, everything is dark. So be sure your light is not darkness."
In Luke 11:34, the metaphor of the "eye" to convey a message about perspective and perception. He is not referring to the physical organ, but rather to the spiritual faculty of perception and how it affects our understanding of reality. He emphasizes that the health or sickness of our "eye" is determined by how we perceive and receive Him.
The metaphor of the oil lamp is also used to illustrate the importance of the Spirit in illuminating our perception. The crucified and risen Jesus is like the wick and the Spirit is like the oil and flame that anoints and ignites the wick, causing it to become radiant. It is only when the Spirit causes us to perceive the light that our perception of reality becomes healthy. This light colors and imparts meaning to our entire reality and is the means by which we truly know anything.