Non-invasive thermal monitoring, such as infrared thermography (IRT), offers a potential alternative to traditional thermometry in veterinary settings. This study aimed to characterize the relationship between maximum eye temperature (ET) and rectal temperature (RT) in dogs. Our field study included 97 observations from 57 shelter dogs whose ET was measured using IRT on 4 separate days. For each observation, 3 consecutive ET measurements were obtained at 10-min intervals, followed by a RT measurement. Device temporal stability was evaluated measurement drift using an insulated box as a controlled environment; the temperature of a fixed point on the inner wall was recorded at 5-min intervals for 1 h using the same thermal camera. Data from both studies were analyzed using repeated-measures linear mixed-effects regression models. In field study, RT, age group, and repetition number were significantly associated with ET. For every 1 °C increase in RT, ET increased by an estimated 0.6 °C (95% CI, 0.3 to 0.9). On average, compared with puppies, adults had lower ET ( β = −0.4 °C; 95% CI, −0. 6 to −0.1), and ET decreased with repeated measurements. Device Stability assessment demonstrated a consistent drop in temperature readings, suggesting information bias related to the camera. Eye temperature measured by IRT was positively associated with RT, and age-related differences were observed. Repeated measurements showed a progressive decline in ET, consistent with device-related measurement drift rather than physiologic change. These findings underscore the importance of accounting for equipment performance characteristics when considering application of IRT. Eye thermography may serve as a noninvasive adjunct for assessing body temperature in dogs; however, device-related behavior should be validated and considered when interpreting readings.
Rostami et al. (Tue,) studied this question.