Methods, devices, and systems for laser eye surgery generally make use of a console (14) that interchangeably accepts multiple types of eye treatment cassettes (16). The cassettes (16) enable one or both of displacement-based or vacuum-based aspiration. The console (14) and the cassette may communicate to establish the functionality of the installed cassette by utilizing a component indigenous to the operation of the cassette (16). A dual-mode cassette (16A) may include a separable holding tank (56) for enabling vacuum-based aspiration. A displacement-based pump (60) may be provided to drain the holding tank (56) while the vacuum system continues to aspirate fluids. A vacuum sensor (64) for controlling the flow of aspirated fluids may have three ports for communicating with a handpiece (12), a displacement-based pump (54), a vacuum-based pump (44), or an irrigation source (46). The handpiece (12) may be vented during vacuum-based aspiration by opening a vent valve interposed between the handpiece (12) and the vacuum source.