Infrared thermal imaging of the inner canthus of the eye as an estimator of body core temperature

Abstract

Several studies suggest that the temperature of the inner canthus of the eye (T ca ), determined with infrared thermal imaging, is an appropriate method for core temperature estimation in mass screening of fever. However, these studies used the error prone tympanic temperature as a reference. Therefore, we compared T ca to oesophageal temperature (T es ) as gold standard in 10 subjects during four conditions: rest, exercise, recovery and passive heating. T ca and T es differed significantly during all conditions (mean DT es 7 T ca 1.80 + 0.898C) and their relationship was inconsistent between conditions. Also within the rest condition alone, intersubject variability was too large for a reliable estimation of core temperature. This poses doubts on the use of T ca as a technique for core temperature estimation, although generalization of these results to fever detection should be verified experimentally using febrile patients.

Use of Thermal Imagery for Estimation of Core Body Temperature During Precooling, Exertion, and Recovery in Wildland Firefighter Protective Clothing

“…We are aware of only one other study using similar technology to estimate temperature during exertion. 16 That study contrasts with the present findings in that the rise of core body temperature during exercise was not detected by the thermal imaging device. However, that study deployed a near-infrared camera with an extended range (0.8-2.5 µm) and lower-resolution (320 × 256) input.…”

Considerations for the measurement of core, skin and mean body temperatures

“…The forehead is one such site, but it is not the warmest, just the warmest among sites commonly evaluated. Instead, the inner canthus of the eye (junction of upper and lower eyelids) provides the closest, surface approximation of deep-body temperature among resting (Barnes, 1967;Ring, 2007), but not exercising individuals (Teunissen and Daanen, 2011). Other potential sites for this approximation include the navel (Barnes, 1967;Olesen and Fanger, 1973) and the lower occiput, neck and upper-thoracic vertebrae (Olesen and Fanger, 1973;Zaproudina et al, 2008;Marins et al, 2014), or regions where body segments are naturally apposed (axilla, groin: Barnes, 1967;Ilsley et al, 1983;Darowski et al, 1991;Childs et al, 1999).…”

Challenges of measuring body temperatures of free-ranging birds and mammals

“…Due to the lack of insulation around the eye, the temperature of this region is often closest to core temperature compared to other peripheral regions. The surface temperature of the eye region is not a reliable predictor of core temperature [96]. However, measurement of temperature of the eye region or other bare skin areas may be useful for detecting stress responses [97,98].…”