Aspiration control

1. Apparatus for controlling aspiration in a microsurgical system, comprising:

a pressurized gas source;

an aspiration chamber;

a vacuum generator;

a surgical device for aspirating tissue;

a first fluid line fluidly coupling said pressurized source and said vacuum generator;

a second fluid line fluidly coupling said vacuum generator and said aspiration chamber;

a third fluid line fluidly coupling said aspiration chamber and said surgical device;

a fourth fluid line fluidly coupling said pressurized gas source and said aspiration chamber independent of said vacuum generator and said surgical device;

a vacuum proportional valve fluidly coupled on said first fluid line between said pressurized gas source and said vacuum generator;

a pressure proportional valve fluidly coupled on said fourth fluid line between said pressurized gas source and said aspiration chamber;

a pressure transducer fluidly coupled to said aspiration chamber;

a proportional controller; and

a computer electrically coupled to said vacuum proportional valve, said pressure proportional valve, said pressure transducer, and said proportional controller;

whereby upon the selection of a desired suction pressure for said aspiration chamber via said proportional controller, said pressure transducer determines an actual suction pressure in said aspiration chamber and provides a first signal corresponding to said determined suction pressure to said computer, and said computer provides a second signal to said vacuum proportional valve and a third signal to said pressure proportional valve to maintain said actual suction pressure proximate said desired suction pressure.

2. The apparatus of claim 1 wherein said computer is configured to provide a range of suction said aspiration chamber, said range being from a small positive value of pressure to a larger negative value of pressure.

3. The apparatus of claim 1 wherein said vacuum generator is a vacuum chip.

4. The apparatus of claim 1 wherein said vacuum generator is a venturi chip.

5. The apparatus of claim 1 wherein said microsurgical system is an ophthalmic microsurgical system.

6. The apparatus of claim 1 further comprising:

a fluid level sensor operatively coupled to said aspiration chamber and electrically coupled to said computer; and

a pump fluidly coupled to said aspiration chamber and electrically coupled to said computer;

whereby upon the selection of a desired suction flow rate for said aspiration chamber via said proportional controller in lieu of said selection of said desired suction pressure, said computer provides a fourth signal corresponding to a pump speed to said pump in response to said desired suction flow rate, said fluid level sensor determines an actual fluid level in said aspiration chamber and provides a fifth signal corresponding to said determined fluid level to said computer, and said computer calculates a suction flow rate in response to said fifth signal and updates said second signal to said vacuum proportional valve and said third signal to said pressure proportional valve to maintain said calculated suction flow rate proximate said desired suction flow rate.