網膜疾患の電気生理学的分析—Stargardt病—黄色斑眼底群

Electrodiagnosis in diseases of the retina: Stargardt's disease-fundus flavimaculatus

（1） Stargardt病一黄色斑眼底群で，高浸透圧応答およびDiamox応答（網膜色素上皮由来の薬物誘発応答）所見によって網膜色素上皮の障害が示唆され，この知見は本症の主病変が網膜色素上皮にあるという組織学的知見を支持する新しい電気生理学的所見である．

（2）我々の薬物誘発応答（高浸透圧応答およびDiamox応答）によって検出された本症の網膜色素上皮障害の程度は，Nobleの検眼鏡的分類（Ⅰ〜Ⅳ群）におけるfleckのひろがりの程度によく対応した．

Stargardt's disease is characterized by a central onset as an atrophic macular lesion ,while, in fundus flavimaculatus, extramacular flecks appear in the course of the disease. We examined four cases of Stargardt fundus flavimaculatus. Each belonged respectively to four subgroups of the disease as proposed by Noble and Carr (1979) : 1) macular degeneration without flecks, 2) macular degenera-tion with perifoveal flecks, 3) macular degeneration with diffuse flecks and 4) diffuse flecks without a macular degeneration. The eases were studied electrophysiologically for the cone receptor cells using rapid off-response in ERG and for the retinal pigment epithelium using hyperosmolarity response and Acetazolamide response (Yonemura and Ka-wasaki 1979).

In the case belonging to group 1, all responses were normal. In the case in group 2, the rapid off-response and acetazolamide response were normal. The hyperosmolarity response was normal in one eye and subnormal in the other indicating retinal pigment epitheliopathy. In the case in group 3, the rapid off-response and hyperosmolarity response were subnormal. The acetazolamide response was subnormal in one eye. In the case in group 4, all the responses were subnormal.

Above electrophysiological findings were consist-ent with the histological features that the primary defect is located in the retinal pigment epithelium (Eagle et al. 1980). Our electrophysiological findings correlated well with the severity of the disease as judged by the fundus manifestations.