Receiver operating characteristics (ROC) curves were separable between the scaled intensities for all stimulus types, and no overlaps were observed in the z-ROC space. Results: Detectability (d a) and the area under the curve (A z) were significantly different between stimulus intensities within each stimulus type (all p < 0.001) but were not different between the stimulus types. Detection theory indices were calculated individually and as groups, which were then analyzed using mixed models and paired t-tests. In the chemical MSDT experiments, 50 trials (20 signal trials each for two intensities and 10 catch trials) were presented, and responses were provided using 4-point confidence ratings. In the cold and mechanical MSDT experiments, 100 trials (80 signal (20 each for 4 intensities) and 20 catch trials) were presented in randomized order, and participants responded with a 5-point confidence rating to each trial. The threshold (baseline for detection theory experiment) for the assigned stimulus type was obtained using the ascending method of limits. The stimulus type was assigned randomly to each visit at the start of the study. A Waterloo Belmonte esthesiometer was used to deliver cold, mechanical, and chemical stimuli to the center of the cornea at three separate study visits. Methods: Thirty-six participants were recruited using convenience sampling. Purpose: To evaluate the detectability of pneumatic corneal stimuli and response bias using multi-stimuli multi-criterion signal detection theory (MSDT). School of Optometry and Vision Science, Faculty of Science, University of Waterloo, Waterloo, ON, Canada.
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