System and method of determining and analysing the ocular biometric status of a patient

Abstract

A computer implemented system and method for determining and analysing ocular refractive error of an eye. The method determines a set of sample biometric factors for a reference sample of eyes from a set of reference sample physical characteristics. Physical characteristics of a patient's eye are measured such that the type of measured patient physical characteristics include some or all of the reference sample characteristic types. Patient biometric factors are then calculated based on the measured and inherent patient physical characteristics and compared with the sample biometric factors to determine the effect of one or more parameters on the ocular refractive error of an eye. The method may calculate the difference between the refractive contribution of the axial length, cornea and internal optics in the patient's eye and the separate contribution from those factors in the sample physical characteristics.

1 . A computer implemented method of determining ocular biometric status of a patient during a period of analysis, comprising the steps of:
 inputting into a computational model the age of the patient and a plurality of measurements of at least one ocular parameter obtained from the patient during a period of analysis, in which the at least one ocular parameter is selected from refraction, axial length, corneal radius, corneal keratometric power, axial length to corneal radius (ALCR) ratio and myopia progression;   generating in the computational model a comparison of each of the plurality of measurements and the age of the patient with population data for the at least one ocular parameter;   converting, by the computational model, each of the plurality of measurements into an age-specific centile parameter;   generating a refractogram which shows the change in the age-specific centile parameters for the at least one ocular parameter over the period of analysis; and   providing in the refractogram, a measurement of the ocular biometric status of the patient based on the progression of the age-specific centile parameters of the at least one ocular parameter over the period of analysis.   
     
     
         2 . A computer implemented method according to  claim 1 , comprising the steps of:
 inputting into a computational model a plurality of measurements of a plurality of ocular parameters obtained from the patient during the period of analysis;   comparing, by the computational model, each of the plurality of measurements and the age of the patient with population data for each of the plurality of ocular parameters;   converting, by the computational model, each of the plurality of measurements into an age-specific centile parameter; and   plotting in a graph the change in the age-specific centile parameters for each of the plurality of ocular parameters over the period of analysis.   
     
     
         3 . A computer implemented method according to  claim 1 , wherein the converting of each of the plurality of measurements into an age-specific centile parameter comprises the step of applying a sigmoid function to the plurality of measurements to account for non-linearity of a biometric parameter to centile relationship. 
     
     
         4 . A computer implemented method according to  claim 2 , in which the plurality of ocular parameters includes at least three and preferably four ocular parameters selected from refraction, axial length, corneal radius, corneal keratometric power, ALCR ratio and myopia progression. 
     
     
         5 . A computer implemented method according to  claim 1 , in which the population data for the at least one ocular parameter employed in the comparison step comprises age and sex matched population data. 
     
     
         6 . A computer implemented method according to  claim 1 , in which the population data for the at least one ocular parameter employed in the comparison step comprises ethnicity, age and sex matched population data. 
     
     
         7 . A computer implemented method according to  claim 1 , which is a method of monitoring effectiveness of myopia control therapy over the period of time and optionally assist a healthcare professional prescribe an alternative therapy for the patient. 
     
     
         8 . A computer implemented method according to  claim 1 , which is a method of predicting risk of developing myopia in a patient. 
     
     
         9 . A computer implemented method according to  claim 1 , which is a method of predicting risk of developing severe myopia in a patient. 
     
     
         10 . A computer implemented method according to  claim 1 , which is a method of predicting severity of myopia in a patient. 
     
     
         11 . A computer implemented system to determine ocular biometric status of a patient undergoing myopia control therapy and comprising:
 a computational model configured to:   receive as an input the age of the patient and a plurality of measurements for an ocular parameter selected from refraction, axial length, corneal radius, corneal keratometric power, axial length to corneal radius (ALCR) ratio and myopia progression obtained from the patient;   compare each of the plurality of measurements and the age of the patient with population data for the at least one ocular parameter and generate a plurality of age-specific centile parameter for the at least one ocular parameter; and   graphically represent in a refractogram the change in the age-specific centile parameters of the at least one ocular parameter over the period of therapy, and   a display system to display the refractogram.   
     
     
         12 . A computer implemented system according to  claim 11 , including a determination system for obtaining from the patient the plurality of measurements for the ocular parameter. 
     
     
         13 . A computer implemented system according to  claim 11 , including a storage system for storing ocular parameter measurements and optionally population data for the ocular parameter. 
     
     
         14 . A computer implemented system according to  claim 11 , in which the computational model is configured to:
 receive as an input the age of the patient and the plurality of measurements for each of the plurality of ocular parameters;   compare each of the plurality of measurements and the age of the patient with population data for ocular parameters and generate a plurality of age-specific centile parameters for each of ocular parameters; and   graphically represent in a refractogram the change in the age-specific centile parameters for each of the ocular parameters over the period of therapy.   
     
     
         15 . A computer implemented system according to  claim 14 , in which the plurality of ocular parameters includes at least three ocular parameters selected from refraction, axial length, corneal radius, corneal keratometric power, ALCR ratio and myopia progression. 
     
     
         16 . A computer implemented system according to  claim 14 , in which the plurality of ocular parameters includes refraction, axial length, corneal radius, corneal keratometric power, ALCR ratio and myopia progression ocular parameters. 
     
     
         17 . A computer program comprising program instructions for causing a computer to perform a method comprising the steps of:
 inputting into a computational model the age of the patient and a plurality of measurements of at least one ocular parameter obtained from the patient during a period of therapy, in which the at least one ocular parameter is selected from refraction, axial length, corneal radius, corneal keratometric power, axial length to corneal radius (ALCR) ratio and myopia progression;   comparing, by the computational model, each of the plurality of measurements and the age of the patient with population data for the at least one ocular parameter;   converting, by the computational model, each of the plurality of measurements into an age-specific centile parameter;   plotting in a refractogram the change in the age-specific centile parameters for the at least one ocular parameter over the period of therapy; and   display the refractogram on a screen or printed format.   
     
     
         18 . A computer program as claimed in  claim 17  embodied on a record medium. 
     
     
         19 . A computer program as claimed in  claim 17  embodied on a carrier signal. 
     
     
         20 . A computer program as claimed in  claim 17  embodied on a read-only memory.