Primary acquired lacrimal duct obstruction (LDO) is a relatively common problem, particularly in elderly people.

Fibrosis is one of the factors contributing to the development of primary acquired lacrimal duct obstruction (LDO).

LIGHT is a cytokine belonging to the tumor necrosis factor (TNF) superfamily of molecules (TNF superfamily member 14, TNFSF14), which stimulates two different receptors: herpes virus entry mediator (HVEM) and lymphotoxin beta receptor (LTβR).

We found significant correlation between the expression of LIGHT and severity of fibrosis assessed histopathologically (Spearman's r = 0.82, p < 0.05). There was also significant correlation between expression of HVEM and LTβR and the severity of fibrosis (Spearman's r = 0.71 and 0.74, respectively; p < 0.05 for both correlations).