Reflectometry/Interferometry System and Method for Corneal Plane Positioning

Abstract

A system for positioning an eye of a patient, for example, for laser ophthalmic surgery includes a reflectometer adapted to receive as input a reflected beam from an anterior surface of a cornea of an eye of a patient. The interferometer is calibratable to a desired position of the corneal anterior surface. A comparator is in signal communication with the interferometer and is adapted to calculate from the input a difference between an actual position and the desired position of the corneal anterior surface. A device is in signal communication with the comparator for moving the patient a distance in a direction for matching the actual position to the desired position of the corneal anterior surface.

1 . A system for positioning an eye of a patient comprising:
 a reflectometer adapted to receive as input a reflected beam from an anterior surface of a cornea of an eye of a patient, the interferometer calibratable to a desired position of the corneal anterior surface;   a comparator in signal communication with the interferometer and adapted to calculate from the input a difference between an actual position and the desired position of the corneal anterior surface; and   a device in signal communication with the comparator for moving the patient a distance in a direction for matching the actual position to the desired position of the corneal anterior surface.   
     
     
         2 . The system recited in  claim 1 , wherein the reflectometer comprises an optical low-coherence interferometer. 
     
     
         3 . The system recited in  claim 1 , wherein the reflectometer comprises a broad-bandwidth light source. 
     
     
         4 . The system recited in  claim 1 , wherein the patient-moving device comprises means for moving a patient support element the distance to achieve the desired position. 
     
     
         5 . The system recited in  claim 1 , wherein the reflectometer and the patient-moving device are connected in a closed-loop feedback configuration. 
     
     
         6 . The system recited in  claim 1 , wherein the comparator comprises a processor having software resident thereon for calculating from the input a signal for being communicated to the patient-moving device to achieve the desired position. 
     
     
         7 . A method for positioning an eye of a patient comprising the steps of:
 receiving a reflected beam from an anterior surface of a cornea of an eye of a patient;   comparing the received reflected beam with a reference beam calibrated to a desired position of the corneal anterior surface;   calculating from the comparing step a difference between an actual position and the desired position of the corneal anterior surface; and   moving the patient a distance in a direction for matching the actual position to the desired position of the corneal anterior surface.   
     
     
         8 . The method recited in  claim 7 , wherein the receiving and comparing steps are carried out with the use of an optical low-coherence interferometer. 
     
     
         9 . The method recited in  claim 7 , further comprising the step, prior to the receiving step, of directing a broad-bandwidth light source to the corneal anterior surface. 
     
     
         10 . The method recited in  claim 7 , wherein the patient-moving step comprises moving a patient support element the distance to achieve the desired position. 
     
     
         11 . The method recited in  claim 7 , wherein the receiving, comparing, calculating, and moving steps are carried out in a closed-loop feedback method. 
     
     
         12 . The method recited in  claim 7 , wherein the calculating step comprises calculating from the received reflected beam a signal for being communicated to a patient-moving device to achieve the desired position.