Abstract
Purpose :
The temperature of the ocular surface and peripheral tissues varies due to tear film dynamics and inflammation. We investigated the association between temperature and blood flow in the ocular anterior segment.
Methods :
We recruited 20 eyes of 20 normal subjects in two experiments: 1 (mean age, 23.4±2.8 years) and 2 (mean age, 24.4±3.2 years). We measured the blood flow and temperature in the ocular anterior segment, i.e., in the upper and lower eyelid skin, tarsal and bulbar conjunctiva, and central cornea. The blood flow and temperature measurements were conducted using laser speckle flowgraphy (LSFG-anterior, Softcare Ltd.) and an ocular surface thermographer (TG-1000, Tomey). In experiment 1, we measured the temperature and blood flow before, immediately after, and 5, 15, and 20 minutes after application of warm compresses. In experiment 2, we measured the temperature and blood flow before and during stimulation using water, menthol, and capsaicin in the mouths of the subjects.
Results :
In experiment 1, the temperature of the upper and lower eyelid skin, tarsal conjunctiva, and central cornea increased significantly (P<0.05, Dunnett’s test) until the 5-minute time point; the temperature of the bulbar conjunctiva increased significantly (P<0.05) until the 10-minute time point. The blood flow in the upper and lower eyelid skin increased significantly (P<0.05) until the 5-minute time point. In experiment 2, the temperature difference between before and during stimulation was correlated significantly with the change rate in the blood flow in the upper (r=0.427, P<0.01, Pearson) and lower (r=0.292, P<0.05) eyelid skin, tarsal conjunctiva (r=0.607, P<0.01), and bulbar (r=0.272, P<0.05) conjunctiva.
Conclusions :
Experiment 1 investigated blood flow when the temperature was raised via warm compresses, and experiment 2 investigated the temperature when the blood flow was raised via stimulation. The results suggested that blood flow and temperature are associated in the ocular anterior segment.
This abstract was presented at the 2019 ARVO Annual Meeting, held in Vancouver, Canada, April 28 - May 2, 2019.