An eye treatment cassette includes a handpiece, a vacuum source, a holding tank, a collection bag, and a displacement-based pump. The handpiece is configured to aspirate fluids from a patients eye. The vacuum source communicates with the handpiece. The holding tank is interposed between the handpiece and the vacuum source, and is configured to hold the aspirated fluids. The collection bag is connected to the holding tank for collecting the aspirated fluids. The pump is coupled to the holding tank and is configured to operate while the vacuum source continues to aspirate fluids via the handpiece to drain the aspirated fluids from the holding tank.
