'anopia' originates from Greek, specifically the word 'anōpía', where the prefix 'a-' meant 'without' and 'ōps/opsis' meant 'sight' or 'vision'.

'anōpía' passed into New Latin/medical Latin as 'anopia' (also attested as 'anopsia') and was adopted into English in medical usage with the same form.

Initially it meant 'absence of sight' in a general sense; over time it has come to be used specifically for loss of vision affecting part or all of a visual field.