Thursday, August 26, 2021

Measuring eye temperature with thermography

The measurement of eye temperature by Infra-red thermography (IRT) is affected by endogenous and environmental factors and does not relate to rectal temperature, a recent study has found. 

The maximal eye temperature (MaxET) measured with IRT has been extensively used in equine research. It is a popular technique as it is non-invasive and does not require direct contact with the individual.


A study, by Anna Jannson and colleagues, published in the journal Physiology and Behavior, investigated factors influencing eye temperature in horses when measured using infra- red thermography (IRT) under field conditions.


The research team took 791 maximal eye temperatures (MaxET) measurements from 32 horses in Sweden in five different months and on five farms over a 12 month period.


They found that in horses observed at rest in their home environment, MaxET is affected by endogenous (sex and breed) and environmental factors (farm, location, and month of the year). MaxET shows no relationship to rectal temperature.


The authors point out that these findings have relevance in both clinical and research settings. 


“This indicates that eye temperature does not appear to be a sensitive method to monitor for example fever, where rectal temperature is traditionally used.”


They add “endogenous (sex and breed) and environmental variation between months were major factors influencing eye temperature and should be considered in the modelling and design of future field experiments.”




For more details, see:


An investigation into factors influencing basal eye temperature in the domestic horse (Equus caballus) when measured using infrared thermography in field conditions

Anna Jansson, Gabriella Lindgren , Brandon D Velie , Marina SolĂ©.

Physiol Behav (2021);228:113218

 doi: 10.1016/j.physbeh.2020.113218

Photo by Anna Jannson et al (CC by 4.0)

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