健康診断で発見される中高年者の網膜色素変性症

Pigmentary retinal dystrophy diagnosed in middle or advanced ages

　発症年齢が40歳以上で，発症から2年以内に東大眼科網膜外来を受診した網膜色素変性症（PRD）20例を検討した。うち14例は自覚症状がないか軽微で，偶然に眼底病変を発見され，当科を紹介されたものである。

　視野障害は軽度ではあるが，自覚症状のない群でも明らかに存在した。しかし同年代の定型PRDの著しい狭窄とは際立った対照を示した。暗順応最終閾値も正常域あるいは110g単位以内の上昇にとどまった。

　発症の遅い老年型PRDの臨床経過は明確にされていないが，同年代の定型PRDに比べて症状は非常に軽い。中高年の検診や眼底検査で発見されるPRDが増加している現在，この型についての十分な認識が必要である。

Clinical features were analyzed in 20 patients who were diagnosed to have pigmentary retinal dystrophy for the first time at or after 40 years of age. At the time of diagnosis, 13 patients had visual complains and 7 were free of subjective symptoms. Their clinical features were compared with those in patients of comparable ages who were diagnosed before 20 years of age. While the fundus features were similar between the two groups, the present 20 patients were characterized by less pronounced visual field defects. Electroretinogram was nonrecordable in all the cases. Dark adaptation showed slight or no distur-bance in 18 eyes, 9 patients, of 10 studied patients. The present findings seemed to support the concept that later age of detection indicates slower progression with milder visual impairment in pigmentary retinal dystrophy.