高血糖状態誘発による屈折異常の発現

Changes in refraction induced by transient hyperglycemia

　若年性糖尿病患者の糖負荷試験で，調節麻痺眼にも近視化と眼圧降下が生じる。こうした屈折調節系の変化が高血糖に基づくものか否かを明らかにする目的で，調節麻痺剤点眼処置をした若年健常人5名に経口糖負荷を行い，血液生化学と屈折調節系の変化を調べた。糖負荷により，血糖値と血漿浸透圧が上昇し，眼圧の降下，屈折度の近視化，浅前房化，水晶体の肥厚が生じた。近視化の程度は，調節麻痺による残余調節力以上の変化を示した。負荷後の血糖値正常化に伴い，眼圧は正常化し，近視化も改善した。以上の結果から，高血糖に伴う近視化は，眼圧降下によって生じたチン小帯張力の減少が誘発した水晶体肥厚に基づくと推論された。遠視化は血糖正常化に伴う近視化の改善によると考えられた。

We evaluated the changes in refraction in 5 healthy adults after peroral administration of 75g glucose. The ages of test subjects averaged 22 years. Cycloplegia and been induced by cyclopentrate instillation. The induced systemic hyperglycemia was followed by transient myopia, shallow anterior chamber and thickening of the lens and ocular hypotension. The amplitude ofmyopia was greater than the power of residual accommodation. Hyperopia and normalization of intraocular pressure occurred 6 hours later along with decrease in plasma glucose level. It appeared that the ocular hypotension was the main cause of induced myopia during hyperglycemia. Decreased tension of zonules of Zinn would have induced thickening of the lens with resultant myopia.