Assessment of tear-evaporation rate in thyroid-gland patients

OBJECTIVE: To assess the tear-evaporation rate in thyroid-gland patients using a VapoMeter. METHODS: Twenty thyroid gland patients aged 18–43 years (mean 34.3±6.3 years) completed the study. Additionally, an age-matched control group of 20 patients aged 18–43 years (32.2±5.1 years) was enrolled in the study for comparison purposes. An Ocular Surface Disease Index dry-eye questionnaire was completed, followed by a test to determine the tear-evaporation rate using the VapoMeter. The test was performed three times per subject by the same examiner. Two readings were obtained each time. RESULTS: Significant differences (P<0.05) were found between mean Ocular Surface Disease Index and tear-evaporation-rate scores within the study and control groups. The average tear-evaporation rate was much higher in the study group (median 41.2 [IQR 41.4] g/m(2)⋅h) than the control group (15.7 [13.7] g/m(2)⋅h). Moreover, the average Ocular Surface Disease Index score for thyroid-gland patients was much higher (15.6 [23.4]) compared to the control group (5.5 [7.50]). CONCLUSION: The tear-evaporation rate in thyroid-gland patients was found to be much higher than normal-eye subjects.