This invention provides an agent containing a geranylgeranylacetone for the prevention, improvement or treatment of retinal diseases, which can fundamentally prevent, improve or treat retinal diseases by directly inhibiting the death of retinal cells, the geranylgeranylacetone is as the following (a), (b) or (c): (a) a mixture of 5E, 9E, 13E geranylgeranylacetone and 5Z, 9E, 13E geranylgeranylacetone, the mixture contains 80 weight % or more of 5E, 9E, 13E geranylgeranylacetone (b) consisting of only 5E, 9E, 13E geranylgeranylacetone (c) consisting of only 5Z, 9E, 13E geranylgeranylacetone.含有香葉基香葉基丙酮之視網膜疾病之預防、改善、或治療劑,藉由直接抑制視網膜細胞之細胞死亡,可根本地預防、改善、或治療視網膜疾病,該香葉基香葉基丙酮係如下述之(a)、(b)、或(c):(a)5E,9E,13E香葉基香葉基丙酮與5Z,9E,13E香葉基香葉基丙酮之混合物,該混合物含有80重量%以上之5E,9E,13E香葉基香葉基丙酮;(b)只由5E,9E,13E香葉基香葉基丙酮所構成;(c)只由5Z,9E,13E香葉基香葉基丙酮所構成。由於本案的圖為實驗數據,並非本案的代表圖。故本案無指定代表圖。
