後部硝子体剥離の超音波B-scan像 体位（頭位）変換に伴う硝子体ゲルの移動

B-scan ultrasonography in posterior vitreous detachment. Movement of vitreous gel due to change in body and head position

　後部硝子体剥離の認められる32症例を対象に，超音波B-スキャン像にて体位（頭位）変換に伴う硝子体ゲルの動きを観察した．結果として，1）完全後部硝子体剥離ではどの体位でも重力の作用により硝子体ゲルが移動することを確認した．2）硝子体ゲルの動きの程度は虚脱の有無が大きく関与した．3）網膜裂孔及び裂孔原性網膜剥離は症例により体位及び頭位変換で硝子体ゲルが裂孔を塞ぐことを確認した．超音波B-スキャンは，裂孔原性網膜剥離と硝子体ゲルの関係を知る上で有用であると結論した．

We applied B-scan ultrasonography to 32 eyes to evaluate the movement of detached posterior hyaloid membrane induced by changes in body or head positioning. In eyes with complete vitreous detachment, the vitreous gel moved vertically irre-spective of the head positioning. Gravitational force seemed to be the chief cause for this finding. The mobility of vitreous gel was more remarkable in eyes with collapsed vitreous than in those with-out. In eyes with retinal tear with or without retinal detachment, appropriate head or body positioning could induce the vitreous gel so as to tamponade the retinal break. B-scan ultrasonography was thus useful in clarifying the relationship between the vitreous gel and the rhegmatogenous detached ret-ina.

Rinsho Ganka (Jpn J Clin Ophthalmol) 42(11) : 1279-1282, 1988