The eye metaphor is difficult to understand and has been interpreted in lots of different ways. It could refer to the practice of looking on others generously, a proper view of possessions1 or an undivided focus.2 Given the context, it most certainly has something to do with the focus of a person’s life. What the eye sees is what the mind reflects on. If the eye lets in light, it benefits the body.
22 L'œil est la lampe du corps. Si ton œil est en bon état, tout ton corps sera éclairé;