A formulation approved both for use in the eye/ear is classified in S03. Formulations approved for eye, ear and nose are also classified in S03. Formulations only licensed for use in the eye or the ear are classified in S01 and S02, respectively.

Most of the drugs in this group are topical preparations. Systemic preparations with clear ophthalmological indications are also classified in this group.
Small amounts of antiseptics in eye preparations do not influence the classification, e.g. benzalkonium.
See also S03 - Ophthalmological and otological preparations.

This group comprises topical drugs used as local anesthetics in the eye.
Local anesthetics for other indications are classified in N01B - Anesthetics, local. Other exceptions, see comments to N01B.
Combinations of local anesthetics and diagnostic agents, e.g. fluorescein, are classified in S01J.