Ambient temperature has a considerable effect on human tear film characteristics. Tear evaporation rate, tear LLT, tear stability, and OST were considerably affected by ambient temperature. Chronic exposure to low ambient temperature would likely result in symptoms of dry eye and ultimately ocular surface disorders.

ObjectiveTo assess the tear-evaporation rate in thyroid-gland patients using a VapoMeter.MethodsTwenty 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.ResultsSignificant 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/m2⋅h) than the control group (15.7 [13.7] g/m2⋅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]).ConclusionThe tear-evaporation rate in thyroid-gland patients was found to be much higher than normal-eye subjects.

Purpose. To investigate the effect of cigarette smoking on the ocular tear film. Methods. Thirty healthy young male cigarette smokers (20–38 years old) and 30 healthy age matched nonsmokers were enrolled in the study. McMonnies questionnaire, slit lamp, and PRT test were used to screen the subjects. Tear samples were collected from the right eyes and tear ferning patterns were observed and graded. Results. The mean MacMonnies scores and TF grades were significantly higher in the smoker subjects (mean ± SD = 9.83 ± 5.22 and 0.96 ± 0.54, resp.) compared to nonsmokers (mean ± SD = 5.96 ± 3.06 and 0.41 ± 0.38, resp.). The mean values obtained from PRT and TBUT tests were 22.23 ± 6.35 mm and 12.17 ± 3.81 s for smokers and 22.16 ± 5.63 mm and 14.13 ± 2.62 s for nonsmokers, respectively. Strong correlations were found between MacMonnies scores and both PRT (r = 0.596) and TF (r = 0.516). There was statistically significant difference in TF grades (p = 0.00), TBUT (p = 0.036) and McMonnies (p = 0.02) between smokers and nonsmokers. Conclusion. Cigarette smoking could have a significant effect on the tear film quality of the eye.

Objective: To investigate the ocular tear film in patients with thyroid disorders using various tests. Methods: The study involved the assessment of the ocular tear film in 20 patients with thyroid disorders (6 men and 14 women) aged 18–43 years (mean±standard deviation=34.3±3.2 years). An age-matched control group consisting of 20 subjects (8 males and 12 females) ranging in age from 18 to 43 years (31.3±2.9 years) was also examined under similar conditions. All patients completed the Ocular Surface Disease Index questionnaire, followed by the tear ferning test within the right eye. A phenol red thread test was carried out 10 mins later followed by the fluorescein tear break-up test with a 10-min gap between the tests being implemented. Results: The median score for the Ocular Surface Disease Index ( P <0.05) showed the condition of mild dry eyes [median (IQR)=15.5 (21.9)] in patients with thyroid disorders compared to the control group [5.6 (3.6)]. The mean score for the phenol red thread test within both the right and left eyes showed acceptable tear volumes of 11.7±8.1 and 10.5±7.4 mm, respectively, but this was much lower ( P <0.05) compared to those recorded within the control group (22.2±6.5 and 20.7±5.2 mm, respectively). In addition, the mean for the tear break-up time ( P <0.05) scores in both eyes within the patients with thyroid disorders revealed a certain degree of eye dryness (4.9±1.6 and 4.2±1.9 s), while the control group showed normal eye scores (13.2±2.6 and 12.3±2.2 s). The median score for tear ferning grades showed eye dryness [2.0 (2.2)] within the study group and normal eyes [1.2 (0.9)] within the control group. Conclusions: Patients with thyroid disorders have a significant level of eye dryness compared to normal eye subjects.