強度近視における網膜色素上皮機能の電気生理学的知見

Electro-oculographical features of high myopia

　強度近視における網膜色素上皮（RPE）機能を電気生理学的に測定し，種々の病像とRPE機能の関連性ならびに他の新生血管黄斑症との病態の違いを検討した。強度近視17例34眼にてL／D比，高浸透圧応答，Diamox応答，メイロン応答の各EOG応答を調べた。眼底が豹紋状のみであってもDiamox応答で異常が検出され，網脈絡膜萎縮や黄斑部出血の発症にRPE機能の広範囲な障害が関与していることが示唆された。また網脈絡膜萎縮が広範囲になるほどRPE機能が障害される傾向があった。高浸透圧応答とメイロン応答の異常が多く，Diamox応答の異常が少ないことから老人性円板状黄斑変性やGrönblad-Stran-dberg症候群に類似した病態が推察された。

We evaluated the electro-oculographical fea-tures in 34 eyes, 17 patients, with high myopia of -8.25 diopters or more. The tests included the L/D ratio, hyperosmolarity response, Diamox response and bicarbonate response. These tests were sup-posed to be concerned with the activities of retinal pigment epithelium (RPE). Diamox response was abnormal in 3 eyes with tigroid fundus only. This finding seemed to indicate widespread abnormality of RPE predisposed to chorioretinal atrophy in high myopia. The abnormal EOG tests became more frequent parallel with the severity of chorioretinal atrophic lesions. All 8 eyes with macular hemor-rhage due to neovascularization manifested abnor-mality in some of the EOG responses irrespective of atrophic lesion. The results of EOG responses in high myopia with diffuse chorioretinal atrophy were compatible with those in senile disciform macular degeneration and angioid streaks, in which the Diamox response was normal and the hyperos-molarity and bicarbonate responses were abnormal.