Venturi and Peristaltic Based Phacoemulsification in Femtosecond Laser Cataract Surgery

The venturi pump makes use of the venturi effect to create a vacuum. The venturi effect creates a vacuum by the flow of a fluid, typically air, over an opening. In many phacoemulsification machines, this requires nitrogen tanks or a self-contained air compressor. The vacuum level is created within a rigid drainage cassette, to which the phaco aspiration tubing is connected. Since there is no milking of the aspiration line, the phaco tubing can be made rigid with low compliance.

"The peristaltic pump uses rollers to compress the phacoemulsification outflow tubing in a peristaltic manner, thereby creating flow and vacuum. The compression of the rollers on the tubing with the rotation of the pump physically moves fluid and creates a continuous milking action on the fluid column, The phaco machine can directly control this flow level, hence the term flow based, however, the preset vacuum level is only achieved once there is occlusion of the outflow line, typically at the phaco needle tip with cataract material."