For therapy and prognosis, the ophthalmologist needs to differentiate between “conventional dry eye” and “dry eye due to active ocular cGvHD.” Scarring of the tarsal plate, severe meibomian gland disease (MGD), loss of goblet cells, and infiltration of the basal conjunctival epithelium and the conjunctival stroma with CD8-positive cells are hallmarks of ocular cGvHD [5-7]. The gene discussed is CD8A; the disease is dry eye syndrome.