Patent ID: 8157379

Claim:
A perimeter for testing a visual field of an examinee in such a state the examinee fixates a predetermined fixation target, comprising: stimulus presentation means for presenting a stimulus having predetermined luminance in order at a plurality of positions where stimulus should be presented in a periphery of said fixation target; response means through which an examiner or the examinee inputs response signals showing that the examinee actually perceived the presented stimulus; luminance judging means for judging said luminance of said stimulus perceived by the examinee for each position where said stimulus should be presented based upon signals from said stimulus presentation means and said response means; representative value storing means for storing “a representative value of the luminance of the stimulus to be perceived with normal eyes” statistically obtained in perimetry that is conducted on a plurality of persons having normal eyes as data in connection with each position where the stimulus should be presented; critical value storing means for storing “a critical value that shows a boundary of the luminance of the stimulus perceived by a predetermined rate of normal eyes” statistically obtained in perimetry that is conducted on a plurality of persons having normal eyes as data in connection with each position where the stimulus should be presented; sensitivity deviation computing means for computing sensitivity deviation that is a difference between a value in connection with the luminance of the stimulus perceived by the examinee and said representative value for each position where the stimulus should be presented based upon said signals from said luminance judging means and said data of said representative value storing means; means for computing ratio to critical value which computes “a ratio to critical value” that is a ratio between a critical value stored in said critical value storing means and said sensitivity deviation computed by said sensitivity deviation computing means for each position where the stimulus should be presented; and means for adding ratios to critical value, which computes a total value of said ratios to critical value computed for each position where the stimulus should be presented or an average value obtained by dividing said total value by number of positions where the stimulus should be presented.