Tear Osmolarity in Ocular Graft-Versus-Host Disease

Purpose: The aim of this study was to evaluate tear osmolarity in patients with chronic graft-versus-host disease (cGVHD) with ocular involvement. Methods: In this observational cross-sectional study of 56 patients with ocular cGVHD referred to the tertiary-care Ocular Immunology and Uveitis Service at the San Raffaele Scientific Institute, Milan, from May 2010 to November 2013, we evaluated the following clinical parameters: Ocular Surface Disease Index (OSDI) symptoms questionnaire, tear osmolarity, Schirmer test, tear film break-up time (TBUT), corneal and conjunctival staining. Results: All patients developed systemic GVHD after undergoing allogeneic hematologic stem cell transplantation. Mean osmolarity was 314.0 +/- 22.1 mOsm/L, mean OSDI score was 26.4 +/- 21.2, mean TBUT was 6.50 +/- 4.75 seconds, and mean Schirmer test value was 3.8 +/- 3.3 mm. Tear osmolarity significantly inversely correlated with TBUT (r(2) = 0.681; P < 0.001). Statistically significant inverse correlation was present with the Schirmer test (r(2) = 0.203; P < 0.001), and positive correlation with the OSDI score (r(2) = 0.188; P < 0.001), but both with low correlation strength. Osmolarity was statistically different in the subgroups according to the Oxford corneal staining scale (P = 0.0006) and to the van Bijsterveld conjunctival staining score (P = 0.006). Conclusions: Tear osmolarity increased in patients with ocular cGVHD, significantly correlated with TBUT and, to a lesser extent, with the Schirmer test value and OSDI. These results emphasize the role of aqueous-deficient and evaporative dry eye disease in patients with cGVHD after undergoing allogeneic hematologic stem cell transplantation. Tear osmolarity may be considered a useful test in diagnostic assessment of dry eye disease associated with cGVHD.