Phacoemulsification machine with post-occlusion surge control system and related method

Abstract

A post-occlusion surge controller 90 for a phacoemulsification machine 30 is adapted to detect a post-occlusion surge in an aspiration conduit 41 of the machine 30 , and to cause the conduit 41 to be vented in response to detecting the surge.

1 . A post-occlusion surge controller for a phacoemulsification machine, wherein the controller is adapted to detect a post-occlusion surge in an aspiration conduit of the machine, and to cause the conduit to be vented in response to detecting the surge.  
   
   
       2 . The post-occlusion surge controller of  claim 1 , wherein the controller is adapted to detect the onset of the surge, and to cause the conduit to be vented in response to detecting the onset of the surge.  
   
   
       3 . The post-occlusion surge controller of  claim 2 , wherein the controller includes a detector for detecting the onset of the surge, and a valve controller for controlling a vent valve of the machine in response to the detector detecting the onset of the surge.  
   
   
       4 . The post-occlusion surge controller of  claim 3 , wherein the detector includes a differentiator for differentiating the output of a vacuum sensor of the machine, and a comparator for comparing the output of the differentiator with a reference value and for outputting a trigger signal depending upon the outcome of the comparison.  
   
   
       5 . The post-occlusion surge controller of  claim 4 , wherein the valve controller includes a timer for outputting a vent valve control signal in response to receiving the trigger signal, and a vent valve driver for driving the vent valve to vent the aspiration conduit in response to the vent valve control signal.  
   
   
       6 . The post-occlusion surge controller of  claim 5 , wherein the valve controller includes a high voltage pulse generator for outputting a high voltage pulse signal to a solenoid of the vent valve in response to the vent valve control signal.  
   
   
       7 . The post-occlusion surge controller of  claim 6 , wherein the valve controller includes a vent valve pre-energiser for pre-energising the solenoid.  
   
   
       8 . A method of controlling a post-occlusion surge in an aspiration conduit of a phacoemulsification machine, the method comprising the steps of: 
 (i) detecting the post-occlusion surge; and    (ii) venting the conduit in response to detecting the surge.    
   
   
       9 . The method of  claim 8 , wherein the step of detecting the surge involves detecting the onset of the surge and the step of venting the conduit is done in response to detecting the onset of the surge.  
   
   
       10 . The method of  claim 9 , wherein the step of detecting the onset of the surge includes determining whether the negative of the rate of change of the vacuum in the conduit with respect to time is greater than or equal to a constant value.  
   
   
       11 . The method of  claim 8 , wherein the step of venting the conduit involve operating a vent valve of the machine to vent the conduit.  
   
   
       12 . The method of  claim 11 , wherein the vent valve vents the conduit for a predetermined period of time.