ABSTRACT
@#AIM: To compare the non-invasive tear film break-up time(NIBUT), tear break up time(TBUT), basal tear secretion(BTS)and blink rate in four ethnic groups: Malay, Chinese, Indian and Nigerian.<p>METHODS: Totally 120 healthy(61 males and 59 females)subjects(without dry eye symptoms and ocular surface disorder)with the age 20 to 39 years were recruited; 30 were Malays, 30 were Chinese, 31 were Indians and 29 were Nigerians. Based on McMonnies questionnaire and clinical examination, normal subjects were selected. NIBUT, TBUT, BTS were assessed in only one eye(right)of each subject and blink rate was also assessed.<p>RESULTS: There was significant difference in the NIBUT, TBUT, BTS and blink rate among 4 different ethnic groups(<i>P</i>=0.018),(<i>P</i>=0.001),(<i>P</i>=0.011), and(<i>P</i>=0.004)respectively. No statistically significant difference of NIBUT, TBUT, BTS and blink rate was found between the genders among different ethnic groups. Indian had higher median for NIBUT(10±6s), TBUT(7±5s)and BTS(20±20 mm)than others races. Chinese had lower median for NIBUT(7.5±4s)and TBUT(4±2s)while Malay had low BTS(9.5±16 mm)among the groups. There was no significant correlation of blink rate with NIBUT, TBUT and BTS(<i>r</i>= -0.119, <i>P</i>=0.195),(<i>r</i>=-0.086, <i>P</i>=0.352),(<i>r</i>= -0.123, <i>P</i>=0.180)respectively.<p>CONCLUSION: This study showed the variability in tear-film measurements values in four ethnic groups.
ABSTRACT
Two types of tear secretion, basic and reflex, have been postulated. Basic secretion is thought to be a constant,slow secretion by the accessory lacrimal glands. Reflex secretion was defined as an increased rate of secretion caused by neural stimulation and thought to be secreted by the main lacrimal gland. The purpose of the present study is to measure the effect of general anesthesia and atropine on basal tear secretion in order to elucidate the association between basal tear secretion and autonomic nervous system. We studied the 84 cases of general operations that were performed between March 1998 and June 1998. Basal tear measurements were made before premedication, 5 minutes after injection of atropine, 10 minutes after general anesthesia and 1 hour after general anesthesia. Basal tear secretion was lower at 5 minutes after injection of atropine than before premedication and markedly decreased after induction of general anesthesia. Therefore, we think that basal tear secretion is closely related to the autonomic nervous system.