Efficacy of wheat hot pack (dry heat) and pottery hot pack (moist heat) on eyelid temperature and tissue blood flow in healthy eyes: a randomized control trial

To investigate the eyelid temperature (Temp) and tissue blood flow (TBF) changes in healthy eyes using wheat hot pack (WHP) and pottery hot pack (PHP). A randomized, double-blind, within-subject crossover study design was conducted in a Thai tertiary care center. All healthy subjects received warm compress treatment with WHP and PHP. The subjects were randomized to receive the WHP or the PHP at the first sequence. Temp and TBF measurements were taken at baseline, and every 2 min during the 10-min application of the heated compresses, and every 2 min for a 10-min duration after the compresses were removed. There were 29 females (96.7%) and 1 male. The mean (SD) age of the subjects was 33.17 (5.21) years. Two warm compresses were able to increase the surface lid Temp significantly from the baseline Temp at every time point of measurement and location. For the WHP application, the maximum surface Temp (SD) of the outer upper lid, outer lower lid, and inner lower lid were 40.07 (0.80) °C, 38.44 (0.91) °C, and 35.83 (0.71) °C, respectively (all P value < 0.001) and under the PHP application, the highest surface Temp (SD) were 40.63 (0.97) °C, 38.32 (1.27) °C, and 35.82 (0.71) °C, respectively (all P value < 0.001). Both WHP and PHP were able to increase TBF significantly with no adverse events and these effects can be sustained until 20 min. The results of this study suggest the potential of using these warm compresses for meibomian gland dysfunction. Further clinical research is needed.