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6.3. Eye-tracking as Assessment and Diagnosis Tool
Subject Auditorium - Rate Auditorium - Duration Bar - Rate Bar - Duration
CA 50.90 / 68.89 224 / 185 62.24 / 19.12 139 / 202
CB 24.96 / 21.11 250 / 157 33.61 / 17.13 166 / 199
CC 6.26 / 16.71 161 / 110 3.81 / 17.99 80 / 183
CD 45.20 / - 240 / - 41.69 / - 143 / -
CE 32.14 / - 153 / - 34.82 / - 274 / -
Table 6.7: Eye blink rates per minute and durations in milliseconds for control subjects. Pretreatment
/ Post-treatment.
Subject Auditorium - Rate Auditorium - Duration Bar Rate Bar Duration
PA 50.47 / 55.82 168 / 138 56.17 / 55.74 157 / 117
PB 82.62 / 71.27 89 / 96 92.23 / 72.65 73 / 93
PC 38.91 / 38.58 517 / 271 51.12 / 62.69 432 / 345
PD 48.38 / - 195 / - 67.13 / - 259 / -
PE 23.89 / - 168 / - 22.71 / - 147 / -
Table 6.8: Eye blink rates per minute and durations in milliseconds for phobic subjects. Pretreatment
/ Post-treatment.
As shown in Tables 6.7 and 6.8, the average number of eye blinks per minute for the phobic
subjects and control group subjects are high when compared to the averages as described
by Schiffman [Schiffman, 2001]. We believe this is due to the equipment used. Indeed, we
have noticed that after 10-15 minutes of eye-tracking use, people started feeling fatigue in
their eye. We thus believe that the eye blink rate comes to be increased due to this fatigue. In
the pre-therapeutic phase, PA and PB both had a rate above 50 eye blinks per minute in the
first exercise and PA, PB, PC and PE all had rates above 50 in the second exercise. In the case
of the control group, only CA had blink rates above 50 blinks per minute in both exercises.
In the post-therapeutic phase, we have not noted any noticeable difference in this behavior;
PA and PB both have values above 50 in the first scene and PA, PB and PC all have values
above 50 in the second scene. Concerning eye blink durations in the pre-therapeutic phase,
PC had blink durations of 517 milliseconds and 432 milliseconds whilst the highest values
in the control group were of 250 milliseconds and 274 milliseconds for the first and second
scenes respectively. Figure 6.10 shows a sample of 10 seconds for subjects CB and PC, both
for the bar scene. In the post-therapeutic phase, however, PC demonstrated an important
decrease in eye blink durations. Moreover, these values are within the range of 100 − 400
milliseconds. Once again, due to the diversity of our tested population and high variability in
results, we can reasonably assume that some phobic subjects presented unusually high blink
rates and durations but we can not affirm it.
6.3.3.4 Subjective ratings
Out of the three phobic subjects who went through the complete therapy, PA and PB both
had visible improvements in their responses to the various scales they filled out before and
after treatment, i.e., the Liebowitz social anxiety questionnaire, the SISST, the BDI, and the
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