System and method for vision examination utilizing fault detection

Abstract

A system and method for performing a vision examination includes displaying a series of visual stimuli for observation by a patient and detecting the patient's visual evoked potentials in response to the visual stimuli. Electrical signals representative of the visual evoked potentials for each stimulus of each series of visual stimuli displayed is amplified, converted to digitized data, recorded and measured. The measured visual evoked potential data is then evaluated and compared to certain predetermined values in order to detect whether or not the measured data is reliable. Data outside of predetermined ranges of values is considered faulty data. For example, the measured data is compared to a maximum value of the output of an amplifier used to enhance the electrical signals, to a predetermined value of the Fourier component at 60 Hz; and to certain ranges to determine if the measured data are outside of expected limits. The occurrence of such data outside these ranges is faulty data. Upon detecting faulty data, new data can be generated until fault free data is obtained or the examination is terminated.

1 . A method for performing a medical test associated with glaucoma comprising 
 displaying a plurality of visual stimuli for observation by one eye of a patient;    detecting the patient's evoked brain potential signals in response to said stimuli through one or more electrodes attached to the patient's scalp;    recording said evoked brain potential signals detected for each stimulus displayed;    obtaining a plurality of fundamental frequency components of a plurality of the evoked brain potential signals corresponding to the periodic visual stimuli;    performing a statistical method to determine a signal-to-noise ratio for said plurality of fundamental frequency components;    comparing said signal-to-noise ratio with a preset critical value; and    displaying an indication of whether there is a high or low likelihood of a disease on a computer monitor based on said digital signal processing.    
   
   
       2 . The method of  claim 1  wherein the data recording comprises 
 amplifying said visual evoked brain potential signals detected from said one or more electrodes attached to the patient's scalp;    converting said visual evoked brain potentials potential signals amplified from analog signals to digital signals.    
   
   
       3 . The method of  claim 1  further wherein the digital signal processing comprises performing a Discrete Fourier Transform on the plurality of the evoked brain potential signals data recorded to obtain the plurality of fundamental frequency components of the plurality of the evoked brain potential signals date-items corresponding to the periodic visual stimuli.  
   
   
       4 . The method of  claim 3  wherein the statistical method is a T 2 circle method.  
   
   
       5 . An apparatus for performing a medical test comprising 
 a computer processor,    a visual stimulus-generating device for presenting visual stimuli to a patient;    a visual evoked potential recording and measuring device;    a computer monitor, and    a computer memory; wherein    the computer processor is programmed by computer software residing in the computer memory to: 
 display a set of visual stimuli on said visual stimulus generating device for observation by a patient;  
 control said recording and measuring device to record a plurality of visual evoked potential signals in response to said set of visual stimuli detected from one or more electrodes attached to the patient's scalp;  
   obtain a plurality of fundamental frequency components of a plurality of the evoked brain potential signals corresponding to the periodic visual stimuli;    perform a statistical method to determine a signal-to-noise ratio for said plurality of fundamental frequency components;    compare said signal-to-noise ratio with a preset critical value; and    determine if the likelihood of disease is high or low based on said comparison.    
   
   
       6 . The apparatus of  claim 5  further wherein the digital signal processing comprises: 
 performing a Discrete Fourier Transform on the plurality of recorded visual evoked potential signals to obtain the plurality of fundamental frequency components of the plurality of the recorded visual evoked potential signals corresponding to the periodic visual stimuli.    
   
   
       7 . The apparatus of  claim 6  wherein the statistical method is a T 2 circle method.  
   
   
       8 . A method of vision examination comprising: 
 displaying to an eye of a patient a plurality of patterns visual stimulation;    detecting electrical signals representative of the patient's visual evoked potentials in response to sensory perception of each pattern displayed by connecting electrodes coupled with a visual evoked potential recording and measuring device to the scalp of said patient;    measuring said visual evoked potentials for each pattern of said plurality of patterns displayed; and    detecting and recording the occurrence of said measured data being outside of a predetermined value thus indicating the occurrence of a fault.    
   
   
       9 . The method according to  claim 8 , further comprising the step of evaluating said data using discrete Fourier transforms and Tcirc 2  statistics.  
   
   
       10 . The method for performing a medical examination according to  claim 9 , further comprising the step of displaying said recorded data.  
   
   
       11 . The method for performing a medical examination according to  claim 9 , wherein said sensory stimuli are visual patterns for visual perception and wherein said evoked potentials in response thereto are visual evoked potentials.  
   
   
       12 . A medical examination apparatus comprising: 
 a processor;    a sensory stimuli display connected to said processor for display of sensory stimuli to a patient;    electrodes in communication with said processor, attachable to said patient's scalp, said electrodes configured to detect electrical signals representative of said patient's evoked potentials in response to said sensory stimuli;    a data storage medium in communication with said processor, for recording data representative of said electrical signals; and    wherein said processor is configured to analyze said data and compare said data to a predetermined value and produce a conclusion regarding whether the likelihood of disease is high or low.    
   
   
       13 . The medical examination apparatus to  claim 12 , further comprising a second display to display said conclusion.  
   
   
       14 . The medical examination apparatus to  claim 12  further comprised of a visually evoked potential measuring device.  
   
   
       15 . A system for performing a medical examination comprising: 
 means for presenting a series of sensory stimuli for perception by a patient;    means for detecting electrical signals representative of the patient's evoked potentials in response to said sensory stimuli;    means for converting said signals into digitized data;    means for recording said data; and    means for analyzing said data and for comparing said data to predetermined values.    
   
   
       16 . The system according to  claim 15 , wherein said means for presenting said series of sensory stimuli comprises a computer controlled visual stimulus generating device.  
   
   
       17 . The system according to  claim 16 , wherein said means for detecting electrical signals comprises a plurality of electrodes connected to the scalp of a patient, said electrodes coupled with a recording and measuring device.  
   
   
       18 . The system according to  claim 17 , wherein said means for converting said signals into digital data comprises an analog to digital converter.