22 “The eye is the lamp of the body. So, if your eye is sound, your whole body will be full of light; 23 but if your eye is not sound, your whole body will be full of darkness. If then the light in you is darkness, how great is the darkness! Matt. 6:22-23
34 Your eye is the lamp of your body; when your eye is sound, your whole body is full of light; but when it is not sound, your body is full of darkness. Luke 11:34
When translators do not know what a passage means they tend to woodenly translate word for word. In doing this, idioms or Hebraisms get lost in translation, and this is certainly one of those.
Quite simply in Hebrew thought, to have a good or sound eye is to be generous, and to have a bad eye is to be stingy.