Clinical Evaluation of the Correlation between Abnormal Blinking and Dry Eye in Children Using a Non-Invasive Ocular Surface Analyzer

Objective: To evaluate the dry eye status of children with abnormal blinking using a slit lamp and non-invasive ocular surface analyzer. Methods: In this cross-sectional study, 85 patients with abnormal blinking (170 eyes), aged 3 to 13 years old, who had a normal ocular surface and were admitted to the Nanjing Medical University Affiliated Eye Hospital from 2017 to 2018 were selected. The slit lamp was used for anterior segment examination, and the Keratograh-D ocular surface analyzer was used to measure noninvasive tear meniscus height (NTMH), noninvasive tear film break-up time (NITBUTf), average noninvasive tear film break-up time (NITBUTav), and the degree of meibomian gland loss to analyze the causes of abnormal blinking in children. Data were analyzed using t-test, ANOVA and rank correlation analysis. Results: The NTMH value of the 85 patients was 0.19±0.05 mm; NITBUTf was 7.5± 5.3 s, and NIBUTav was 8.6±5.6 s. The degree of meibomian gland loss was 0.7±0.8. In meibomian gland photography, 78 had no missing meibomian glands; in 62 eyes meibomian gland loss was less than 1/3; in 27 eyes meibomian gland loss was more than 1/3 and less than 2/3; in 3 eyes meibomian gland loss was greater than 2/3. The morphology of the meibomian glands in 46 eyes was abnormal. Among the 85 children with abnormal blinking, 77 (91%) were diagnosed with dry eye and 8 (9%) were normal. Tear deficiency accounted for 10 cases (13%); excessive evaporation dry eye accounted for 25 cases (32%); and mixed tear deficiency and evaporation accounted for 42 cases (55%). There was no significant correlation between gender and NTMH, but there was a significant correlation between gender and both NIBUTf and NIBUTav (r=0.31, 0.32, P<0.001). There was no significant cor-relation between age and both NTMH and NITBUTf, but there was a slight positive correlation between age and NIBUTav (r=0.19, P<0.017). The course of abnormal blinking was negatively correlated with NTMH, NITBUTf and NITBUTav (r=-0.61, -0.37, -0.40, P<0.001). Conclusion: Dry eye is the main cause of abnormal blinking in children with normal ocular surfaces. The ocular surface analyzer is a non-contact, non-invasive and repeatable rapid exami-nation method, which is highly valuable in evaluating eye surface conditions in children with abnormal blinking. Key words: abnormal blink; non-invasive ocular surface analyzer; dry eye in children; stability of tear film