Ophthalmic surgical device

An ophthalmic surgical device comprising:

• an irrigation fluid line configured to have irrigation fluid flow therethrough from an irrigation fluid container to an ophthalmic surgical handpiece;
• an aspiration fluid line configured to have aspiration fluid flow therethrough from the ophthalmic surgical handpiece to a collecting container;
• a first volumetric flow arranged meter, wherein the first volumetric flow meter is positioned upstream of the ophthalmic surgical handpiece in a flow direction, and wherein the first volumetric flow meter is configured to determine a first volumetric flow rate in the irrigation fluid line;
• a second volumetric flow arranged meter, wherein the second volumetric flow meter is positioned downstream of the ophthalmic surgical handpiece in the flow direction, and wherein the second volumetric flow meter is configured to determine a second volumetric flow rate in the aspiration fluid line;
• an occlusion determination apparatus coupled to the first volumetric flow meter and to the second volumetric flow meter;
• wherein the occlusion determination apparatus is configured to acquire a time curve of the first volumetric flow rate and a time curve of the second volumetric flow rate,
• wherein the occlusion determination apparatus quantitates a difference between the time curve of the first volumetric flow rate and the time curve of the second volumetric flow rate and one or more stored standard time curves of the first volumetric flow rate in the irrigation fluid line and of the second volumetric flow rate in the aspiration fluid line for respectively different known occlusion states, thereby detecting an occlusion state in the aspiration fluid line based on symmetry or correlation of the time curve of the first volumetric flow rate and the time curve of the second volumetric flow rate to the one or more stored standard time curves;
• a control device, wherein the control device is configured to receive an occlusion state signal from the occlusion determination apparatus at a control device input, and wherein the control device is configured to output a control signal for at least one operational parameter of the ophthalmic surgical handpiece to the ophthalmic surgical handpiece at a control device output;
• a first fluid pump, wherein the first fluid pump is positioned between the irrigation fluid container and the first volumetric flow meter in the flow direction, and wherein the first fluid pump is configured to convey irrigation fluid to the ophthalmic surgical handpiece;
• a second fluid pump, wherein the second fluid pump is positioned between the second volumetric flow meter and the collecting container in the flow direction, and wherein the second fluid pump is configured to convey aspiration fluid to the collecting container;
• a first timing element, wherein the first timing element is configured to receive the occlusion state signal at a first timing element input, wherein the first timing element is configured to ascertain as a function of time a first irrigation fluid target pressure depending on the occlusion state signal, and wherein the first timing element is configured to output a signal for the first irrigation fluid target pressure of the first fluid pump at a first timing element output;
• a second timing element, wherein the second timing element is configured to receive the occlusion state signal at a second timing element input, wherein the second timing element is configured to ascertain, as a function of time, a first aspiration fluid target pressure depending on the occlusion state signal, and wherein the second timing element is configured to output a signal for the first aspiration fluid target pressure of the second fluid pump at a second timing element output;
• a first evaluation apparatus, wherein the first evaluation apparatus is configured to receive the signal for the first irrigation fluid target pressure at a first input, wherein the first evaluation apparatus is configured to receive a signal for a second irrigation fluid target pressure at a second input, and wherein the first evaluation apparatus is configured to supply a signal for an irrigation fluid control pressure of the first fluid pump at a first evaluation apparatus output;
• a second evaluation apparatus wherein the second evaluation apparatus is configured to receive the signal for the first aspiration fluid target pressure at a first input, wherein the second evaluation apparatus is configured to receive a signal for a second aspiration fluid target pressure at a second input, and wherein the first evaluation apparatus is configured to supply a signal for an aspiration fluid control pressure of the second fluid pump at an output;
• third and fourth timers connected to said first and second evaluation devices, respectively, wherein the third and fourth timers supply corresponding ones of said fluid target pressures;
• and,
• a foot operated unit connected to said third and fourth timers and configured to specify the speed at which a change in-the irrigation fluid target pressure and the aspiration fluid target pressure should occur.