A stereoscopic viewing technology is expected to improve diagnostic performance in terms of reading efficiency by
adding one more dimension to the conventional 2D images. Although a stereoscopic technology has been applied to
many different field including TV, movies and medical applications, physiological fatigue through reading stereoscopic
radiographs has been concerned although no established physiological fatigue data have been provided. In this study,
we measured the α-amylase concentration in saliva, heart rates and normalized tissue hemoglobin index (nTHI) in blood
of frontal area to estimate physiological fatigue through reading both stereoscopic radiographs and the conventional 2D
radiographs. In addition, subjective assessments were also performed.
As a result, the pupil contraction occurred just after the reading of the stereoscopic images, but the subjective
assessments regarding visual fatigue were nearly identical for the reading the conventional 2D and stereoscopic
radiographs. The α-amylase concentration and the nTHI continued to decline while examinees read both 2D and
stereoscopic images, which reflected the result of subjective assessment that almost half of the examinees reported to feel
sleepy after reading. The subjective assessments regarding brain fatigue showed that there were little differences
between 2D and stereoscopic reading.
In summary, this study shows that the physiological fatigue caused by stereoscopic reading is equivalent to the
conventional 2D reading including ocular fatigue and burden imposed on brain.