The eyes represent seeing, and seeing represents thoughts or judgment. Alternate translation: "be wise in his own thoughts" or "think he is wise" (See: [[rc://en/ta/man/translate/figs-metaphor]])
The abstract noun "understanding" can be expressed as a verb. Alternate translation: "who understands" (See: [[rc://en/ta/man/translate/figs-abstractnouns]])
This is an idiom that means the poor person will be able to determine whether or not the rich person is really wise. Alternate translation: "will see his true nature" (See: [[rc://en/ta/man/translate/figs-idiom]])