There are no changes from Matthew 6:22–23.
The key to understanding these verses is understanding the nature of the image of “The light of the body is the eye.” In Mediterranean cultures, it was believed that one’s eyes saw by emitting light rather than receiving it. They were the instruments through which an internal light illuminated the world. The next phrase is “if … thine eye be single.” The original meaning of “single” was unmixed, which does not necessarily make the interpretation of this image of “the light of the body is the eye,” any easier. However, if we see that the word unmixed is synonymous with pure, the image becomes clearer. The image refers to the type of light that was known in the ancient world. In oil lamps, pure and good oil produced a steady light. A mixed fuel source, or a corrupted fuel, would cause the flame to sputter. Thus, the imagery all deals with the internal light of the body.
That physical understanding is transformed into a spiritual message. The gospel is what is inside, not outside. Therefore, if we, in secret, or inside, follow the commandments, then the light of the eye represents a whole body filled with light. In some ways, it also speaks to the way we see the world, where the quality of our righteousness alters the way we view the world. We see others through the lens of what we have come to be.