Variability in the measurement of corneal temperature using a noncontact infrared thermometer

Purpose: To assess the variability of corneal temperature and the reproducibility of its measurement by means of a noncontact infrared thermometer in healthy subjects. Methods: The THI-500 noncontact infrared thermometer (Tasco Japan, Osaka, Japan) was used for the measurement of corneal temperature. The reproducibility of corneal temperature measurements was assessed for 5 consecutive temperature readings obtained within 45 min or within 5 days. In addition, the interocular difference in corneal temperature and the diurnal temperature changes of the cornea were assessed. For each experiment, 10 healthy subjects were recruited. Results: The reliability of 5 consecutive corneal temperature measurements obtained within 45 min and within 5 days was 97.92 and 85.35%, respectively. Interocular differences in corneal temperature were not statistically significant (p = 0.70). Average corneal temperature varied significantly during the day (p < 0.0001), with lower corneal temperature readings during the morning hours compared to those obtained during the afternoon. Conclusion: The assessment of corneal temperature by means of noncontact infrared thermometry is highly reproducible. Corneal temperature varies throughout the day, and this variation is independent of variations in environmental temperature. Copyright (C) 1999 S. Karger AG, Basel.