Efficacy of hydroxypropyl-guar drops in improving tear film index and ocular surface dynamics using two treatment methods under a controlled desiccating environment.

AIM: This study aimed to assess the efficacy of hp-guar eye drops on tear film index and ocular surface dynamics under desiccating conditions using protection and relief treatment modalities. METHODOLOGY: The 12 normal, non-dry eye participants were subjected to adverse environmental conditions using a Controlled Environment Chamber (CEC) where the relative humidity (RH) was 5% and the ambient temperature was 21 °C. The participants were screened for ocular symptoms, tear osmolarity, ocular surface temperature (OST), tear production using the Ocular Surface Disease Index questionnaire (OSDI), OcuSense TearLab Osmometer, FLIR System ThermaCAM P620, and Schirmer strips. Tear production was calculated by the Tear Function Index test (TFI). RESULTS: The mean tear film osmolarity decreased significantly from 296 mOsm/L at 40% RH to 285 mOsm/L at 5% RH (p = 0.01). Conflicting responses were seen for osmolarity in protection and relief. Mean tear osmolarity was significantly higher in the protection method in comparison to the relief method (p = 0.005). The mean TFI increased from 557 at 40% to 854 at 5% (p = 0.02). A significant increase in TFI was observed in the relief method in comparison with both 40% (p = 0.001) and 5% (p = 0.04). In the relief method, the mean TFI score went up to 1139 when hp-guar was installed. A significant improvement in ocular comfort was experienced in both the protection (p = 0.041) and relief (p = 0.010) methods at 5% RH. The instillation of hp-guar drops in the relief method resulted in a significant reduction in OST. The mean OST dropped to 33.01 ºC, significantly lower than the recorded OST for both normal (p = 0.040) and dry (p = 0.014) environmental conditions. CONCLUSION: Hp-guar drops significantly improve tear film parameters under a desiccating environment, however, tear film parameters respond differently to the management modalities. In the protection method, tear film osmolarity was protected against a dry environment, while in the relief mode, an improvement in tear production and a decrease in ocular surface temperature were seen. Hp-guar performance could be maximized for the management of exposure to adverse environments by using a treatment protocol that targets the most affected parameters in each group of patients. Using CEC has the potential to provide researchers with a readily available method to evaluate the efficiency of tear supplementation.

Evaluation of Tear Evaporation Rate in Subjects with a High Body Mass Index.

AIM: This study evaluated the tear evaporation rate (TER) in subjects with a high body mass index (BMI) and tested the correlation between BMI and dry eye. METHODS: Thirty male subjects aged 18 - 38 years (26.4 ± 4.0 years) with a high BMI (26.4 - 47.0 kg/m2) were enrolled in the study. In addition, a control group of 30 males aged 20 - 36 years (24.0 ± 3.6 years) with a normal BMI (< 25 kg/m2) participated in the study for comparison. Each subject completed the ocular surface disease index (OSDI), followed by the TER measurement using a handheld VapoMeter. RESULTS: Significant differences (Wilcoxon test; p = 0.002 and 0.001) were found between the median scores of the OSDI (10.3 [3.7] vs. 5.9 [7.2]) and TER (35.5 [13.1] vs. 15.5 [12.8] g/m2 h) in the study and control groups, respectively. The OSDI indicated dry eye in 60.0% of subjects in the study group (n = 18). The TER measurements showed that 76.7% of subjects in the study group (n = 23) had dry eyes. A medium correlation (r = 0.569; p = 0.001) was found between the OSDI scores and TER measurements. CONCLUSIONS: The means of the tear evaporation rate and the ocular surface disease index scores are significantly higher in subjects with a high BMI compared with the control group. Therefore, a high BMI is considered a risk factor for dry eye. The measurement of the tear evaporation rate using a handheld VapoMeter is a simple and rapid method to detect dry eyes in combination with other tools.

Evaluation of Tear Film Osmolarity Among Diabetic Patients Using a TearLab Osmometer.

PURPOSE: The purpose of the present study is to determine the effects of type 2 diabetes mellitus on tear osmolarity using a TearLab Osmolarity system. Moreover, the relationship between tear film osmolarity and ocular surface discomfort in controlled and uncontrolled diabetic patients was assessed. MATERIALS AND METHODS: This study included 20 male type 2 diabetic patients aged 20 to 70 years (mean ± SD 49±12). A control group (18-43 years; 32.2 ± 6.5 years) consisting of 40 male subjects was also enrolled for comparison. The tear osmolarity was measured using the TearLab Osmolarity System. The ocular surface disease index questionnaire (OSDI) was used to assess ocular discomfort symptoms. RESULTS: The mean tear osmolarity was 297 ± 8.00 and 296 ± 11 mOsm/L for controlled and uncontrolled diabetic subjects, respectively, while the average osmolarity in the control group was 299 ± 8.00 mOsm/L. No significant differences were detected in tear osmolarity between the control and diabetes groups. The ocular surface disease index questionnaire (OSDI) score was significantly higher in the diabetic patient group. No significant correlation was found between tear osmolarity and OSDI scores. CONCLUSION: The ocular discomfort symptoms score in diabetic patients was significantly higher compared to normal eye subjects. Tear osmolarity was not significantly different in diabetic patients. This finding may be explained by a lack of relationship between tear film parameters and diabetic severity; tear film parameters may correlate more with diabetic duration rather than severity. Therefore, studies focused on diabetes duration and tear film parameters are recommended.