Correlation between ocular surface characteristics and tear lymphotoxin-alpha in patients with type 2 diabetes mellitus of different courses.

OBJECTIVE

This study aims to investigate the correlation between ocular surface characteristics and tear Lymphotoxin-alpha (LTA) levels in type 2 diabetes mellitus (T2DM) patients at different disease durations, in order to explore the potential role of LTA as a biomarker for the pathogenesis of diabetic dry eye syndrome (DES).

METHODS

This retrospective controlled study evaluated ocular surface function in 90 subjects from June 2023 to June 2025: Group A (T2DM ≤ 5 years), Group B (T2DM > 5 years) as the study groups, and a control group (non-DM), 30 per group. Masked researchers assessed ocular surface indicators [Ocular Surface Disease Index (OSDI) score, non-invasive tear meniscus height (NTMH), non-invasive first tear film break-up time (NITBUTf), non-invasive average tear film break-up time (NITBUTav), meibomian gland loss score, eyelid margin assessment (EMS), corneal fluorescein staining score (CFS), and the Schirmer's I test (SIt)]. Tear LTA concentration was detected using immunochromatography. The relationships between the duration of T2DM and different parameters were assessed using Spearman's correlation method.

RESULTS

The control group had higher tear LTA levels (1.79 ± 0.32 ng/mL) than both T2DM groups (Group A: 0.64 ± 0.14 ng/mL; Group B: 0.51 ± 0.12 ng/mL; P < 0.05). Ocular surface function (NTMH, NITBUTf, NITBUTav and SIt) declined, while symptom and sign scores (OSDI, EMS and CFS) increased in T2DM groups, worsening in Group B (P < 0.05). DES prevalence was higher in Group A (26.67%) and Group B (53.33%) than controls (6.67%) (P < 0.05). Tear LTA levels showed a strong negative correlation with T2DM duration, OSDI, meibomian loss, EMS, and CFS (all P < 0.05), but positively with NTMH, NITBUTf, NITBUTav, and SIt (all P < 0.05).

CONCLUSION

Ocular surface function in patients with T2DM deteriorates with the prolongation of disease duration. The decrease in tear LTA level may be associated with the immune imbalance mechanism of diabetic DES.