超音波生体顕微鏡で検出された虹彩毛様体嚢腫

Detection of iridociliary cysts by ultrasound biomicroscope

　超音波生体顕微鏡（ultrasound biomicroscope：UBM）を用いて虹彩毛様体嚢腫を観察した。嚢腫は440眼中22眼（5.0％）で発見され，すべて両眼性であった。部位は，虹彩毛様体境界部が14眼，虹彩後方周辺部が8眼であり，毛様体のほぼ全周にわたって多発性にあった。狭隅角眼での嚢腫の頻度は，120眼中10眼（8.3％）であった。狭隅角眼で観察された嚢腫の中で4眼は，急性緑内障発作後に発見された。レーザー虹彩切開術後も眼圧が下降せず，縮瞳剤点眼後に隅角が開放し，眼圧が正常化し，UBMで嚢腫は伸展，扁平化したことが観察された。生体眼において虹彩毛様体嚢腫は高頻度にあり，閉塞隅角緑内障の一因となることが推定され，UBMは，この嚢腫の発見に非侵襲的で有効な手段であると評価される。

We examined 440 normal and diseased eyes using an ultrasound biomicroscope, UBM. Cysts in the iris or the ciliary body was detected in 22 eyes, 5.0%. The condition was always bilateral. The cyst was located at the iridociliary junction in 14 eyes and posterior to the peripheral iris in 8. Multiple occurrence was the rule located along the whole circumference. Cyst was present in 10 of 120 eyes with narrow angle, 8.3%. In 4 of the 10 eyes, cyst was detected after acute attack of closed angle glaucoma. Laser iridotomy failed to lower the intraocular pressure. Normalization of pressure was obtained after miosis by topical pilocarpine. UBM showed flattening of the cyst after miosis. The present findings show that iridociliary cyst is a relatively frequent occurrence and that it serves as one of the underlying causes of closed angle glaucoma. UBM is an effective and noninvasive means of detecting iridociliary cysts.