Tear Film Break-up Time in Bipolar Disorder

OBJECTIVE Ocular dryness is a well-recognized adverse side effect of many topical and systemic medications. In psychiatry, patients who have consumed such drugs as lithium carbonate and sodium valproate frequently experience dry eye symptoms. The purpose of this study was to compare tear film stability between patients who use these drugs with those patients who are not on medication. METHODS After obtaining informed consent, the tear film break up time (TBUT) test was performed in 96 eyes of 48 subjects. The subjects were placed in to three groups. Participants included two groups of euthymic bipolar disorder patients (16 cases each) with history of pharmacotherapy for more than two years. Patients in each group were taking only one type of mood stabilizer (lithium carbonate or sodium valproate). In addition,16 age-matched bipolar patients who did not take any topical or systemic medications were included in a control group. Values of TBUT were compared between the three groups using the student's t-test. RESULTS The mean tear film break up time (TBUT) in test groups were 4.88 seconds± 0.34(lithium group), 4.81 seconds ± 1.60 (valproate group) and 15seconds± 2.0(control group), respectively. No statistically significant differences were observed between the first and the second groups in TBUT values, but significant differences were found between the two groups and the control group (P< 0.0001). CONCLUSION The results of this study show that lithium carbonate and sodium valproate contribute to decrease of tear film break up time, resulting from dryness of the eyes.