Abstract
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, K(max,) 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, K(max), 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.