Systems and methods for mapping the ocular surface

Abstract

Examples of methods and apparatus for an accurate measurement of the anterior surface of the eye including the conical and scleral regions are disclosed. The measurements provide a three-dimensional map of the surface which can be used for a variety of ophthalmic and optometric applications from astigmatism and keratoconus diagnostics to scleral lens fitting.

1 . (canceled) 
     
     
         2 . A system for measuring an anterior surface topography of an eye, the system comprising:
 a projection system configured to emit light towards an ocular surface of the eye and to project a single pattern or a sequence of patterns onto the ocular surface;   an image sensor configured to record one or more images of the patterns resulting from the projected pattern or sequence,   an analysis system comprising computing hardware configured to determine a topographic map of the ocular surface from the one or more images of the patterns,   wherein the analysis system is configured to obtain measurements of a plurality of segments of the ocular surface and to combine the measurements into a single measurement covering an area larger than the measured segments.   
     
     
         3 . The system of  claim 2 , further comprising a fixation target system configured to permit a gaze of the eye to be sequentially fixed at a plurality of gaze directions. 
     
     
         4 . The system of  claim 3 , wherein the fixation target system comprises one or more of: a plurality of targets to be illuminated in sequence, an emissive screen configured to display stationary or moving gaze fixation targets, or one or more targets that can be physically moved to direct the gaze to a specified direction. 
     
     
         5 . The system of  claim 2 , wherein the single measurement includes regions of the ocular surface normally hidden by an eyelid. 
     
     
         6 . The system of  claim 2 , wherein the system is configured to analyze the information related to the topographic map of the ocular surface for a design of a contact lens for the measured eye. 
     
     
         7 . The system of  claim 6 , wherein the contact lens is a scleral contact lens. 
     
     
         8 . The system of  claim 2 , wherein the system is configured to analyze information related to the topographic map of the ocular surface and to predict a fit of a contact lens on the eye. 
     
     
         9 . The system of  claim 8 , wherein the contact lens is a scleral contact lens. 
     
     
         10 . The system of  claim 2 , wherein the system is configured to communicate information related to the topographic map of the ocular surface to a contact lens manufacturing system for manufacturing of a custom fit contact lens. 
     
     
         11 . The system of  claim 10 , wherein the custom fit contact lens is a scleral contact lens. 
     
     
         12 . The system of  claim 2 , wherein the projection system comprises a single projector and the image sensor comprises one or more image sensors. 
     
     
         13 . A method for calculating a three-dimensional topographical model of an anterior ocular surface of an eye, the method comprising:
 under control of an ocular topographic mapping system comprising computer hardware:   receiving images of projected patterns that are reflected or emitted from the anterior ocular surface;   analyzing the received images; and   determining, based at least in part on the analyzed images, a composite measurement of topography of at least a portion of the anterior ocular surface,   wherein the composite measurement comprises measurement of at least one region of the anterior ocular surface that is hidden by an eyelid in at least one of the received images.   
     
     
         14 . The method of  claim 13 , wherein determining the composite measurement of topography of at least a portion of the anterior ocular surface comprises combining a plurality of individual topography measurements of portions of the anterior surface of the eye taken at a plurality of orientations of an optical axis of the eye. 
     
     
         15 . The method of  claim 14 , further comprising determining the plurality of orientations of the optical axis of the eye by at least one of the following:
 obtaining a location of a gaze fixation target;   analyzing a 3-dimensional topography of the anterior surface of the eye; or   analyzing a 3-dimensional orientation of a known anatomical structure of the eye.   
     
     
         16 . The method of  claim 15 , wherein the anatomical structure of the eye comprises the corneal limbus. 
     
     
         17 . The method of  claim 15 , wherein the anatomical structure of the eye comprises the pupil. 
     
     
         18 . The method of  claim 14 , wherein determining the plurality of optical axis orientations comprises using one or both of: evaluating an automated computer algorithm, or receiving input from an operator of the ocular topographic mapping system. 
     
     
         19 . The method of  claim 18 , wherein determining the plurality of optical axis orientations comprises receiving a location of the corneal limbus determined by the operator of the ocular topographic mapping system. 
     
     
         20 . The method of  claim 14 , wherein combining the plurality of individual topography measurements comprises determining boundaries of the individual topography measurements using an automated algorithm. 
     
     
         21 . The method of  claim 14 , wherein combining the plurality of individual topography measurements comprises receiving information relating to boundaries of the individual topography measurements obtained by an operator of the ocular topographic mapping system.