Apparatus for modelling ocular structures

Abstract

An apparatus for motion compensated modelling of a parameter of an eye, comprising: a first measuring means for measuring a plurality of position parameters of the eye with respect to an optical reference coordinate system of the apparatus; a second measuring means for measuring an interference signal at a plurality of optical reference coordinates, wherein the measurement of the plurality of position parameters and measurement of the interference signal are time synchronised; means for correcting the interference signal to account for a displacements of a parameter of the plurality of position parameters; and means for modelling the eye parameter based at least in part on the corrected interference signal.

1 . An apparatus for motion compensated modelling of a parameter of an eye, comprising:
 a first measuring means for measuring a plurality of position parameters of the eye with respect to an optical reference coordinate system of the apparatus;   a second measuring means for measuring an interference signal at a plurality of optical reference coordinates, wherein the measurement of the plurality of position parameters and measurement of the interference signal are time synchronised;   means for correcting the interference signal to account for a displacements of a parameter of the plurality of position parameters; and   means for modelling the eye parameter based at least in part on the corrected interference signal.   
     
     
         2 . The apparatus according to  claim 1  wherein the plurality of position parameters include lateral displacement along an x axis of the optical reference coordinate system, lateral displacement along a y axis of the optical reference coordinate system and axial displacement along a z axis of the optical reference coordinate system. 
     
     
         3 . The apparatus according to  claim 1  wherein the plurality of position parameters include cyclorotation around the z-axis. 
     
     
         4 . The apparatus according to  claim 1  wherein the plurality of position parameters include rotation around the x axis and rotation around the y axis. 
     
     
         5 . The apparatus according to  claim 1  wherein means for determining a displacement comprises means for interpolating between measurements of the plurality of position parameters. 
     
     
         6 . The apparatus according to  claim 1  further comprising means for determining a reference location of the second measuring device and means for correcting said reference location based on the measured position parameters. 
     
     
         7 . The apparatus according to  claim 1  wherein the means for correcting further comprises means for correcting an optical path length based on a difference in an optical path length between an off-axis ray-traced path length and a path length along the z axis of the optical reference coordinate system. 
     
     
         8 . The apparatus according to  claim 1  wherein the first measuring device further comprises means for measuring a position parameter based on a retinal reflex. 
     
     
         9 . The apparatus according to  claim 7  further comprising means for iteratively correcting the optical path length. 
     
     
         10 . The apparatus according to  claim 1  wherein the first measuring device comprises means for illuminating a targeted ocular surface ( 116 - 120 ) with a least one incident light beam and means for direct at least two light beams returning from the illuminated ocular surface to an image forming device ( 110 ). 
     
     
         11 . The apparatus according to  claim 10  wherein the ocular surface includes an anterior corneal surface, a posterior corneal surface, an anterior lens surface, a posterior lens surface or a retinal surface. 
     
     
         12 . The apparatus according to  claim 1  wherein the first measuring means is selected from a list including a Purkinje Mirror Imaging device, an Optical coherence Tomography Device or a Scheimpflug Imaging System and the second measuring means comprises an optical coherence device. 
     
     
         13 . The apparatus according to  claim 11  further comprising means for determining refraction at the ocular surface and correcting the modelled eye parameter based on the determined refraction. 
     
     
         14 . An method for motion compensated modelling of a parameter of an eye, comprising:
 measuring a plurality of position parameters of the eye with respect to an optical reference coordinate system of the apparatus;   measuring an interference signal at a plurality of optical reference coordinates, wherein the measurement of the plurality of position parameters and measurement of the interference signal are time synchronised;   correcting the interference signal to account for a displacements of a parameter of the plurality of position parameters; and   modelling the eye parameter based at least in part on the corrected interference signal.   
     
     
         15 . A computer readable programmable medium carrying a computer program stored thereon which when executed by a processing module implements the method according  claim 14 .