The Importance Of The Relationship Between Tear Meniscus Height And Lipid Layer Thickness Instability As Diagnostic Indicators For Dry Eye

To investigate the impact of tear meniscus height (TMH), particularly its interaction with lipid layer thickness (LLT), on OSDI levels as a clinical parameter in dry eye disease.

This study was conducted as a retrospective study and included data from 268 patients who underwent evaluation of dry eye parameters prior to cataract surgery between July 2024 and April 2025.

Patients' age, sex, BUT, ocular surface score(OSS), average LLT, standard deviation(SD) of LLT, maximum LLT, minimum LLT, TMH and other anterior ocular parameters were investigated. TMH was measured using anterior segment OCT, and patients were classified into three groups based on TMH: low (< 0.2 mm), normal (0.2–0.35 mm), and excessive (> 0.35 mm). Ordinal logistic regression models including interaction terms were fitted to evaluate whether the association between LLT parameters and OSDI level differed by TMH group.

The interaction between SD of LLT and TMH group was primarily attributable to differences in the SD of LLT effect between the Normal group and both the Low (p = 0.043) and Excess (p = 0.015) groups, with no significant difference between the Low and Excess groups (p = 0.64). Within the normal TMH group, SD of LLT was not significantly associated with OSDI severity. In contrast, in the low and excessive TMH groups, increasing SD of LLT was associated with greater OSDI severity. No significant interaction was observed between average LLT and TMH group in relation to OSDI level (p = 0.200).

When TMH is either low or excessively high, the impact of LLT instability on OSDI levels becomes more pronounced. In the diagnosis of dry eye disease, greater consideration should be given to SD of LLT rather than average LLT when TMH is low or excessively high. TMH levels should not be assessed solely as a continuous variable, but rather stratified into distinct groups for more meaningful evaluation.