Corneal surface temperature and tear secretion in young and adult aqueous tear deficient guinea pigs

Purpose To evaluate changes in ocular surface temperature and tear secretion in young and adult control and tear‐deficient ( DE ) guinea‐pigs. Methods Tearing rate ( TR ) was measured using phenol red threads (30s). Tear break‐up time ( TBUT ) was measured after fluorescein instillation. Corneal surface temperature ( CST ) was recorded continuously in the full open eye during 30s after the eye opening using an infrared thermal camera (InfRec R300 SR , Nippon Avionics). Images were analyzed using dedicated software. Results Tearing rate was significantly higher and TBUT was significantly lower (p < 0.05) in adult (12‐18 months) compared with young (2‐4 months) animals (p < 0.001). CST immediately after the eye opening had a value around 36.5°C in control eyes in young and adult animals. Most tear deficient eyes had initial CST over 37°C. The slope of temperature decrease during the interblink period was similar for all ages. As expected, DE animals had significantly lower TR (p < 0.001) and TBUT (p < 0.01) than intact animals, although their initial CST and the slope of interblink temperature decrease were similar to age‐matched control eyes. Conclusions Tear‐deficient eyes show higher CST values immediately after blink suggesting the presence of inflammation. Temperature reduction during the interblink period was not modified in DE , despite the reduced stability of tear film.