網膜中心静脈閉塞発症後の網膜機能の回復

Recovery of retinal function in a case of central retinal vein occlusion

　我々は網膜中心静脈閉塞（CRVO）発症後4年間にわたる経過観察中，合計8回網膜電図（ERG）　を記録した。ERG　は発症後1か月はsupernormal responseを示し，3か月ではnega-tive （−） responseを示したが，その後，徐々に回復しほぼ正常に達した。一連の　ERG　記録はCRVO後の網膜循環障害による網膜機能の変化をよく示し，ERGは網膜循環障害の網膜機能の評価に有効であった。また，一般に予後が悪いと考えられているnegative ERGを示した重度の出血型CRVOでも可逆性の網膜機能の回復があり得ることが示唆された。

A 65-year-old female sought medical advice due to visual impairment in her right eye since 1 month before. She manifested typical fundus features of hemorrhagic central retinal vein occlusion. The visual acuity in the affected eye was hand motion. The single-flash electroretinogram (ERG) showed negative response with b: a ratio less than 1. The ERG findings gradually improved during the follow-up period of 4 years. Oscillatory potential, which was initially absent, became discernible 1 year after onset of disease. The b: a ratio became normal and the visual acuity improved to 0.3 at the end of 4 years.

The present case is an exception to the widely held belief in the poor visual prognosis of hemorr-hagic central retinal vein occlusion, particularly when the ERG is of negative type. The case also illustrates the importance of ERG as a guide in evaluating the retinal function.