Where does “ὀπτική” come from?

ὀπτική (Ancient Greek) comes from Ancient Greek ὀπτικός, from Ancient Greek ὄψις, from Ancient Greek ὄψ, from Proto-Hellenic wókʷs, from Proto-Indo-European wekʷ- — to speak, to sound out.

ὀπτική (Ancient Greek): feminine nominative/vocative singular of ὀπτικός