'anisopia' originates from Greek, specifically from the prefix 'aniso-' meaning 'unequal' and the suffix '-opia' from Greek 'ōps' meaning 'eye' or 'sight'.

'anisopia' was formed in medical/Modern Latin usage from the Greek elements and entered English in medical contexts to denote unequal vision between the eyes.

Initially, the term described the literal sense of 'unequal sight'; over time it has remained focused on the clinical meaning of differing visual acuity between the two eyes.