Ultrasonic cataract extraction with acoustic horn.

An ultrasonic lens-disintegrations system is added to the aspiration side of an irrigation-aspiration system. It incorporates an acoustic horn of which one part is a stainless steel cone 4 cm long with a 1 cm diameter base. From the apex of the cone projects the other part, viz. a 22 gauge needle, which is inserted into the anterior chamber at the limbus temporally (left eye) and which carries aspirated lens fragments with saline out into a duct drilled 2 cm into the cone along its axis. At that point the duct turns at right-angles to leave the cone; a polythene tube connects the duct with the aspiration syringe. A vibration generator (sandwich transducer) initiates ultrasonic vibrations which the needle-cone combination magnifies about 100-fold at the tip of the needle. Saline input to and output from the anterior chamber are maintained exactly equal (and simultaneous) by means of a 'push-pull' system of twin reciprocating hand-driven 30 ml. syringes (Fig. 7). Saline input is through a 25 gauge needle at the limbus at 6 o'clock (left eye).