"Eye Eye" is a colloquial expression that means "yes" or "I agree". While it may not have any synonyms in the strictest sense, there are many other expressions that can convey a similar meaning. For example, one might say "you got it" or "I hear you" as a way of indicating agreement. Other phrases, like "absolutely" or "you bet" can be used to express enthusiasm or certainty. Still others, such as "I understand" or "that makes sense", can convey comprehension without necessarily indicating agreement. Ultimately, the choice of expression will depend on the context and the speaker's natural way of communicating.