Caecus (m) and caeca (f) are adjectives meaning 'blind'.
Caecilius is that adjective turned into a surname; if borne by a woman, the female form was
Caecilia. This was originally a plebeian name, and might well have been used originally to refer to a blind person, or maybe to someone who had a blind spot - a kind of prejudice - about something. The name existed long before Christianity.
I'm a bit vague about saints, but wasn't St
Dunstan the patron of the blind?