Protective agent for retinal nerve or optic nerve

Abstract

To provide a protective agent for a retinal nerve or an optic nerve, which exhibits its efficacy through a mechanism that is different from that for a conventional therapeutic agent and can be ingested over a long period. [MEANS FOR SOLVING PROBLEMS] Disclosed is protective agent for a retinal nerve or an optic nerve, which comprises a compound having an inhibitory activity on an aldose reductase, such as a compound represented by the general formula below, as an active ingredient. Preferably, the compound is (2S,4S)-6- fluoro-2',5'-dioxospiro[chromane-4,4'-imidazolidine]-2- carboxamide. wherein X represents a halogen atom ora hydrogen atom; R and R independently represent a hydrogen atom or a C1-6 alkyl group which may be substituted, or R and R together with a nitrogen atom located at the base of R and R or additionally together with other nitrogen atom or an oxygen atom may form a 5- to 6-membered heterocyclic ring.