| 摘要 |
There is disclosed herein a system for providing control of multiple functions needed to perform eye surgery. A microprocessor based system controls a vacuum generation system using venturis and linear valves and a pneumatic system for driving vitrectomy probes and pneumatic scissors in either a variable frequency, multicut mode or a proportional cut mode where the cutting pressure is proportional to the position of a foot operated position sensor. The frequency of the vitrectomy probe cutting action can also be controlled and the level of vacuum can be controlled from a foot operated position sensor which can also be used to turn on or off a fragmentation device. The footswitch can also be used to turn irrigation fluid on or off, and the flow rate can be controlled from a control on the front panel. By making a certain foot motion in any certain aspiration modes, reflux of the aspiration line can be controlled. The vacuum level is continuously monitored over all aspiration conditions and adjusted to stay as close as possible to the desired vacuum level. A cassette proximity sensing system senses the presence of a cassette, and aids the user in drawing in and latching the cassette. The vacuum integrity of the cassette is automatically checked by the microprocessor each time one is drawn into the machine. The microprocessor also monitors the cassette for fullness an initiates a transfer to empty one bottle of the cassette into another bottle for storage when the first bottle becomes full. A back-up system checks the accuracy of cassette liquid level sensing apparatus by double checking for liquid in the line leading to the vacuum generation system. If water is detected, a fluid transfer from one bottle of the cassette to the other is initiated.
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