Control of pulse duty cycle based upon footswitch displacement
Phacoemulsification apparatus includes a phacoemulsification handpiece having a needle and an electrical circuitry for ultrasonic vibrating the needle. A power source provides pulsed electrical power to the handpiece electrical circuitry and an input is provided for enabling a surgeon to select an amplitude of dislighted pulses and a pulse width. A control system and pulse duty cycle is provided for controlling the off duty cycle to insure heat dissipation before a subsequent pulse is activated, including a foot pedal switch.
1. A phacoemulsification apparatus comprising:
a phacoemulsification handpiece having a needle, the needle configured to be ultrasonically vibrated;
a power source configured to provide pulsed electrical power to the handpiece;
an irrigation source configured to provide irrigation fluid to the eye;
an aspiration source configured to provide aspiration of fluid from the eye;
a power level controller; and
a footswitch configured to enable a surgeon to select a first mode comprising a variable amplitude of the electrical pulses or a variable duty cycle of the electrical pulses;
wherein the power level controller is configured to vary the amplitude or duty cycle when the footswitch operates within a first zone of a plurality of defined zones according to a nonlinear profile provided within the first zone within an available directional travel range of the footswitch, the footswitch also configured to select a second mode comprising at least one of an irrigation flow and an aspiration flow, the second mode varying by operating the footswitch within a second zone of the plurality of defined zones within the available directional travel range of the footswitch.
2. The phacoemulsification apparatus of claim 1 , further comprising a computer configured to control the power source to provide electrical power at a pulse repetition rate of between about 25 and about 2000 pulses per second.
3. The phacoemulsification apparatus of claim 2 , wherein the computer is further programmed to control the power source such that electrical pulses further comprise an off duty cycle.
4. The phacoemulsification apparatus of claim 1 , wherein the footswitch is further configured to control aspiration flow when operating the footswitch in a first portion of the second zone and irrigation/aspiration flow when operating the footswitch in a second portion of the second zone.
5. The phacoemulsification apparatus of claim 1 , wherein the apparatus is responsive to a selected pulse amplitude and a selected duty cycle for controlling an off duty cycle to ensure heat dissipation before a subsequent pulse is activated.
6. The phacoemulsification apparatus of claim 1 , wherein the footswitch is configured such that duty cycles are selected in a non-linear fashion based upon footswitch displacement.
7. The phacoemulsification apparatus of claim 1 , wherein the second mode of the footswitch enables a linear selection of at least one of the irrigation flow and the aspiration flow.
8. A method for operating a phacoemulsification system, the system including a phacoemulsification handpiece having a needle, an irrigation source, an aspiration source, a power source configured to provide pulsed electrical power to the handpiece, and a footswitch, said method comprising:
applying pulsed electrical power from the power source to the handpiece;
receiving input from a user via the footswitch;
selecting a first mode comprising a variable amplitude of the electrical pulses or a variable duty cycle of the electrical pulses varying by operating the footswitch within a first zone of a plurality of defined zones according to a nonlinear profile provided within the first zone within an available directional travel range of the footswitch; and
selecting a second mode comprising at least one of an irrigation flow and an aspiration flow, the second mode varying by operating the footswitch within a second zone of the plurality of defined zones within the available directional travel range of the footswitch.
9. The method of claim 8 , further comprising controlling the power provided to the handpiece to have a pulse repetition rate of between about 25 and about 2000 pulses per second.
10. The method of claim 8 , wherein electrical pulses further comprise an off duty•cycle.
11. The method of claim 8 , wherein the footswitch is further configured to control aspiration flow when operating the footswitch in a first portion of the second zone and irrigation/aspiration flow when operating the footswitch in a second portion of the second zone.
12. The method of claim 8 , wherein the system is responsive to a selected pulse amplitude and a selected duty cycle for controlling an off duty cycle to ensure heat dissipation before a subsequent pulse is activated.
13. The method of claim 8 , wherein said footswitch is configured such that duty cycles are selected in a non-linear fashion based upon footswitch displacement.
14. The method of claim 8 , wherein selecting the second mode enables a linear selection of at least one of the irrigation flow and the aspiration flow.
15. The method of claim 8 , wherein a continuously variable footswitch displacement over a given footswitch angular range results in a continuously variable duty cycle.