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.
