The Hebrew that is translated as “his eyes are darker than wine” or similar in English is translated in Kutu as “his eyes are redder than wine.”

“To say someone has ‘dark’ eyes here is a very negative thing. (…) [Here it is understood] that they are talking about abundance of wine and milk and people eyes are bloodshot from drinking much wine and the teeth are healthy from much milk.” (Source: Pioneer Bible Translators, project-specific translation notes in Paratext)

See also beautiful eyes and blind.