Blink behaviour, tear film stability and ocular surface interactions in New Zealand Chinese children.

PURPOSE: The increasing use of soft contact lenses for paediatric myopia control highlights the importance of understanding ocular surface physiology before lens wear. However, little is known about how eyelid morphology and blink behaviour interact with tear film stability and ocular surface characteristics in Asian children. This study characterised baseline ocular surface physiology and examined these relationships in Chinese children living in New Zealand.

METHODS

Sixty-one Chinese myopic children aged 7-12 years with no prior contact lens experience had non-invasive tear breakup time (NIBUT), fluorescein tear breakup time (TBUT), Ocular Protection Index (OPI), corneal and conjunctival staining, lower-eyelid meibomian gland morphology, and upper and lower lid lid wiper epitheliopathy (LWE) assessed using the MYAH and slit lamp examination. Blink patterns were classified as complete or incomplete. Correlation and multivariable regression analyses were performed to evaluate associations between blink behaviour, tear film stability, and ocular surface parameters.

RESULTS

Incomplete blinking was observed in 53% of children and differed significantly across eyelid morphology groups, occurring most frequently in single eyelids (100%) and incomplete double eyelids (76.5%). Children with incomplete blinking demonstrated significantly reduced NIBUT compared with complete blinkers (median 5.9 vs 8.1 s, p = 0.021). Reduced tear film stability was significantly associated with both upper lid LWE (rₛ = -0.43, p < 0.001) and lower lid LWE (rₛ = -0.26, p = 0.040), although the association was stronger for the upper lid. After adjustment for age and sex, NIBUT remained independently associated with upper lid LWE (B = -0.060, p = 0.018).

CONCLUSION

Incomplete blinking and reduced tear film stability are highly prevalent in Chinese children and are strongly influenced by eyelid morphology. Reduced tear film stability was independently associated with upper lid LWE, supporting a potential biomechanical interaction between blink dynamics, tear film instability, and lid-ocular surface friction.