Correlations between tear lymphocytotoxin-a (LT-α) level and disease severity in adult keratoconus.

PURPOSE: This study aimed to investigate tear lymphocytotoxin-α (LT-α) levels in adult keratoconus patients and identify the correlations between LT-α and the disease severity of keratoconus.

METHODS

In this cross-sectional study, tear samples from 100 keratoconus patients (KC group) and 67 healthy controls (HC group) were collected. LT-α levels were tested immediately after collection using a commercially available point-of-care test (POCT). Visual acuity, corneal tomography, anterior segment optical coherence tomography (AS-OCT), tear film parameters, including non-invasive break-up time (NI-BUT), tear meniscus height (TMH), lipid layer thickness (LLT), and meibomian glands, were also tested. Corneal topography values (K1, K2, Kmax, and astigmatism) were derived from the tomography data.

RESULTS

The tear LT-α levels in the HC group were significantly higher than those in the KC group (p = 0.038). The NI-BUT, TMH, and LLT were significantly lower, while the meiboscore was higher in the KC group than in the HC group (p < 0.001). In the KC group, patients were further divided into preclinical stage, initial stage, and complete stage groups. Significant differences in tear LT-α levels were found among the three subgroups. Within the KC group, LT-α levels were significantly correlated with various parameters, including thinnest corneal thickness, best-corrected visual acuity (BCVA) (LogMAR), K1, K2, Kmax, and astigmatism values. However, no significant correlation was observed between the tear LT-α level and tear film parameters. Within the control group, no significant correlation was identified between the tear LT-α level and corneal topography or tear film parameters.

CONCLUSION

Our data demonstrated an association between tear LT-α levels and the severity of keratoconus, implying that immune-related factors may be involved in the pathogenesis and progression of the disease.