Here is the full question:

The rules say, “In Duo Interpretation, focus may be direct during the introduction [the performers may look at each other] but must be indirect [off-stage] during the performance itself.” Is looking at each other considered looking each other in the eyes, their body, or both? In other words, could a performer look at the hand of their partner during a performance?

That is an excellent question, and the answer may be interpreted differently depending upon regional norms (there may even be variation in your specific state – some states have limitations in movement and focus delineated in their rules). In some contexts, only eye contact would be a violation of that rule, whereas in other contexts, looking directly at your partner in any way may result in lower scores by the judges.

To be safe in most contexts, you may want to gaze past the hand itself (the hand will be in your peripheral vision so you can tell where you are) so that you maintain offstage focus.