Abstract: In a method of checking the threshold values of a subject's perception of visual stimuli, for each one of a selection of test series, the estimated error of a threshold value estimate of the test series is used to judge whether the test series is to be continued or not. This means that a test series may be discontinued as soon as the threshold value thereof can be determined with acceptable accuracy. Preferably, a posterior probability function is used for estimating the error. An apparatus for carrying out the method includes a control unit operating according to the method.

Abstract: In a method of testing a subject's perception of successively presented visual stimuli, a predetermined preliminary response time window is used at the beginning of the test to preliminarily classify the visual stimuli as "seen" or "not seen" depending on whether or not a response is received from the subject within the preliminary response time window. To permit reclassification of the visual stimuli at a later stage, the time of reception of every response, whether outside or within the preliminary response time windows, is stored. When an appropriate number of stimuli have been presented, a subject-adapted response time window is determined on the basis of the stored times of reception of the responses. This subject-adapted response time window is used for reclassifying the preliminarily classified stimuli.