Morphological changes in the meibomian gland in children with tic disorders

Background: Since blinking accelerates meibomian gland (MG) expression, abnormal blinking in children with tic disorders may be associated with the morphological changes of the MGs. Our study aimed to quantitively evaluate the morphology of the MG in these children.Methods: In this prospective case-control study, we examined 68 eyes of 68 children with tic disorders, 47 eyes of 47 children with dry eye, and 45 eyes of 45 healthy children at the Hangzhou Branch of the Eye Hospital of Wenzhou Medical University from October 2020 to March 2021. We used an Oculus Keratograph 5M (K5M) to capture the MG images, noninvasive breakup time (NIBUT), and tear meniscus height (TMH). An automated method was used to analyze MG length, width, area, gland diameter deformation index (DI), and gland signal index (SI). Parameters across the three groups were assessed using Kruskal-Wallis test followed by Mann-Whitney test with Bonferroni correction for multiple comparisons. Results: The eyes in the tic disorders group exhibited lower MG length and area values compared with those of the other groups (all P values <0.001) and lower MG width values compared with those of children in the dry eye group (P=0.009). The tic disorder and dry eye groups both had a larger percentage of eyes with a u-shaped MG duct when compared with the control group (P<0.001 and P=0.017). The dry eye group had the lowest TMH and NIBUT values (both P values <0.001). The NIBUT values in the tic disorder group were lower than those in the control group (P<0.001). No significant correlations were detected between clinical tests and MG morphology in any of the groups.Conclusions: Blinking disorders have a significant impact on MG morphology. In children with tic disorders, more attention should be devoted to monitoring the MG over time.