A new agent for the treatment of a corneal epithelium disorder, which acts directly on corneal epithelial cells, is provided. Disclosed is an agent for the treatment of a corneal epithelium disorder, the agent comprising a compound of Formula (1) or a salt thereof as an active ingredient: wherein A is an aromatic ring, a heterocyclic ring, or an aliphatic ring; R2, R3, and R4, which may be identical or different, each independently are, for example, a hydrogen atom, a halogen atom; B is an aromatic ring which may have a substituent, a heterocyclic ring which may have a substituent, or an aliphatic ring which may have a substituent; —X—, —Y—, and —Z—, which may be identical or different, each independently are O—, —NH—, —NR5—, —S—, —SO—, —SO2—, —CH2—, —CR6R7—, or —CO—; and —W— is —NR1—, —O—, or —CR8R9—.