超音波白内障手術時の前房内圧変化の自動記録と制御

Automated recording and control of intracameral pressure during phacoemulsificaion-aspiration surgery

　安全な超音波乳化吸引術のためには安定した前房内圧が必要である。そこで術中の前房内圧を経時的に自勤測定し，その変化量を記録した。さらに模擬眼を用いて能動的な前房内圧制御方法を検証した。手術は最大吸引圧330mmHg，流量33ml／分の設定で，点眼麻酔下3.0mm幅角膜一面自己閉鎖創で行い，既報の眼内圧モニタリングシステムを用いて前房内圧の値を0.5ミリ秒ごとに自動取得した。前房内圧変化率は，定常圧状態時よりサージ現象時に，より大きな絶対値を示した。前房内圧の制御は，一定内圧への制御よりも，内圧の変化量を抑える微分制御法のほうがより効果的にサージ現象を抑制できた。

Safe phacoemulsification requires stable anterior chamber. We recorded the change of intracameral pres-sure during phacoemulsification using an automated system. We also tested the novel active regulatory methods of the intracameral pressure. Maximum vacuum pressure and flow rate were set at 330mmHg and 33 ml/min, respectively. Phacoemulsification was done under topical instillation of anesthetic, using 3.0 mm-corneal, single-plane, self-sealing incision. Intracameral pressure was continuously recorded at 0.5 msec intervals using an intracameral pressure-moni-toring system previously reported. The rate of change of the intracameral pressure was larger in absolute value during surge phenomena than during constant pressure-states. As for the control regulation of intracameral pressure, differ-ential regulation, which suppresses the rate of change of the pressure, was more effective than constant-regulation in order to prevent surge phenomenon.