TNF and dry eye syndrome: Notably, Usuba et al. further investigated the dry eye condition among 14 patients with AS who underwent tumor necrosis factor inhibitor (TNFi) therapy at 3 and 12 months after the administration of TNFi, and found that Schirmer's test at the baseline, 3 and 12 months was 10, 17.5, and 20 mm/5 min, respectively (30).