To investigate the distribution of tear film lipid layer thickness (LLT) and the relationship between symptoms and signs of dry eye and tear film LLT in the population of Taishitun Community in Beijing.

A cross-sectional study. From May 2016 to August 2016, three streets of Taishitun Community were randomly selected as survey districts and 540 persons were taken as investigation subjects. Every participant completed 6 items of dry eye examinations as follows: questionnaire (Ocular Surface Disease Index, OSDI), measurement of tear film LLT, tear film break-up time (TBUT), corneal and conjunctival staining, SchirmerⅠtest and the infrared meibomian photography. According to their age, all participants were divided into four groups: junior group (<18 years old), youth group (18 to 40 years old), middle-aged group (41 to 59 years old) and the elderly group (over 60 years old). With the OSDI criteria, no dry eye symptom group (score, <12 points), mild to moderate dry eye symptom group (score, 12 to 32) and severe dry eye symptom group (score, 33—100) were included. With the statistical methods of variance analysis and multivariate Logistic regression analysis, distribution of the variables of LLT and the relationship between dry eye symptoms and LLT were studied.

A total of 473 residents finally participated in this study, and the response ratio was 87.6%. The values of LLT were normally distributed. The average LLT was (59.87±18.50) nm [(60.16±19.15) nm in males and (59.67±18.57) nm in females], and the comparison of LLT with different genders was not statistically significant (t=0.198, P=0.843). The tear film LLT of four different age groups had statistical significance (F=15.092, P<0.05), and increased with age [(56.10±18.33) nm in the junior group, (54.60±16.29) nm in the youth group, (60.61±19.18) nm in the middle-aged group and (73.25±14.58) nm in the elderly group]. The LLT was inversely proportional to the severity of dry eye symptoms. With a thinner LLT, the symptoms of the subjects turned severe. In the elderly with different degrees of symptoms, the LLT was significantly different (F=0.019, P<0.05), while in the youth and middle-aged groups with different degrees of symptoms, the LLT was not significantly different (F=0.096, P>0.05. F=0.538, P>0.05). In the OSDI symptom questionnaire, only blurred vision and decreased visual acuity were related to the tear film LLT (P<0.05). There was no significant correlation between the TBUT, SchirmerⅠtest result, meibomian gland loss rate and the tear film LLT (P>0.05).

In Taishitun Community of Beijing, the values of tear film LLT had a normal distribution. The LLT was positively correlated with age, but inversely correlated with the severity of the symptoms of dry eye. There was no significant correlation between the LLT and the TBUT, SchirmerⅠtest result and meibomian gland loss rate.(Chin J Ophthalmol, 2017, 53: 495-501)

Dry eye syndromes; Meibomian glands; Lipids; Tears; Interferometry; Cross-sectional studies