Tear physiology in dry eye associated with chronic GVHD.

The purpose of this study was to compare tear physiology characteristics of chronic GVHD (cGVHD)-associated dry eye to dry eye caused by Sjogren's syndrome (SS), a extreme form of aqueous-deficient dry eye, and meibomian gland dysfunction (MGD), the major cause of evaporative dry eye. Tear turnover rate, evaporation and osmolarity along with meibomian gland dropout and lipid layer interferometric patterns were assessed in the right eyes of 12 patients with dry eye associated with cGVHD, 12 age-matched patients with SS and 12 age-sex matched subjects with MGD. In cGVHD, the decrease in tear turnover rate was similar (P=0.33), but the number of non-functioning meibomian glands was significantly higher (P<0.01) than in SS. Tear evaporation rate in cGVHD dry eye was found to be similar to that in MGD (P=0.36) and significantly higher than in SS (P<0.01). The lipid layer was most unstable in cGVHD compared with other groups. There was no variation in tear volume across all groups. Although statistical significance was not detected, the mean tear osmolarity (333.51±14.67mOsm/L) was highest in cGVHD. Major aspects of tear physiology were severely impaired in cGVHD-associated dry eye.