Yes, you've got it! You're quite a sharp one, Eliza.

[He smiles as he points to the eye in her hand.]

As you've determined, "pupula duplex" is the medical term for a condition where a person is born with two pupils instead of just one in their eye. Sometimes they may appear to overlap one another as the case tends to be with polycoria, while a different person may have two pupils that are separate from one another, like how this glass eye appears here.