How many letters does the top answer for “of or relating to or causing constriction of the pupil of the eye” have?

The most common answer is miotic (6 letters).

Crossword clue: of or relating to or causing constriction of the pupil of the eye

2 answers found in Letterora's clue database (Wikidata facts, Open Trivia DB, WordNet and Webster definitions — all licensed sources).

miotic 6 letters wn-def

a drug that causes miosis (constriction of the pupil of the eye)

myotic 6 letters wn-def

a drug that causes miosis (constriction of the pupil of the eye)

of or relating to the pupil of the eye 60% similar → pupillary