PROBLEM TO BE SOLVED: To provide a prophylactic or therapeutic agent of chorioretinal denaturation diseases without substantially accompanying neovascularization, e.g. atrophic age-related macular degeneration, retinitis pigmentosa, gyrate atrophy of the choroid and retina, and further chorioretinal disorders associated with the above diseases.SOLUTION: This compound expressed by formula (1) or its pharmaceutically acceptable salt has an inhibitory effect toward photo receptor cell death in a mouse light disorder model. Therefore, it is useful as the prophylactic or therapeutic agent of chorioretinal denaturation diseases without substantially accompanying neovascularization, eg. atrophic age-related macular degeneration, retinitis pigmentosa, gyrate atrophy of the choroid and retina and further chorioretinal disorders associated with the diseases.COPYRIGHT: (C)2012,JPO&INPIT【課題】実質的に新生血管を伴わない網脈絡膜変性疾患、たとえば、萎縮型加齢黄斑変性、網膜色素変性症、脳回転状網膜脈絡膜萎縮症、さらにはそれらの疾患に伴う網脈絡膜障害の予防または治療剤を提供すること。【解決手段】式(1)で表される化合物またはその医薬的に許容される塩は、マウス光障害モデルにおける、光受容体細胞死に対して抑制効果を有する。よって、実質的に新生血管を伴わない網脈絡膜変性疾患、たとえば、萎縮型加齢黄斑変性、網膜色素変性症、脳回転状網膜脈絡膜萎縮症、さらにはそれらの疾患に伴う網脈絡膜障害の予防または治療剤として有用である。【選択図】なし