調節麻痺眼におけるマニトールで惹起された屈折調節系の変化

Changes in refraction in cycloplegic eyes following systemic hyperosmotic mannitol

　筆者らは以前，アセタゾラミド内服により，低眼圧ならびに近視化とそれに相当した調節力低下が生ずることを報告した。

　今回，こうした屈折調節系への変化が眼圧降下に基づくものなのかを明らかにするため，アトロピン点眼処置した健常人3名にマニトール静注を行い，屈折調節系の変化を調べた。眼圧の降下に伴い，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，アトロピン投与による残余調節力以上の変化を示した。以上の結果より，低眼圧に伴う近視化は，眼圧降下によって遠心方向の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。

We evaluated the changes in refraction in 3 young volunteers after intravenous 20% mannitol infusion. Cycloplegia had been induced in the eyes by previous atropine instillation. Systemic man-nitol induced myopia, shallow anterior chamber and thickening of the lens in addition to ocular hypotension. The amplitude of induced myopia was greater than the residual accommodation in thecycloplegic eyes. The observed findings are in agreement with our previous observation that ocu-lar hypotension following systemic acetazolamide induces myopia and impaired accommodation. It appeared that ocular hypotension was the main cause of induced myopia in both experiments. Decrease in tension of zonules of Zinn would have induced thickening of the lens with resultant myo-pia.