Ocular surface characteristics and impression cytology in patients with active versus inactive Thyroid Eye Disease.

Abstract

To compare the clinical findings, tear film function and impression cytology between patients with active and inactive Thyroid Eye Disease (TED). A total of 56 patients with TED and 30 controls were recruited in this prospective observational cohort study. TED patients were divided into active TED and inactive TED types according to a seven-point modified formulation of the Clinical Activity Score (CAS). All participants underwent full eye examinations including Ocular Surface Disease Index (OSDI) score, tear film break-up time (TBUT), fluorescein staining and Schirmer I test. Thirty nine patients with thyroid-associated orbitopathy (TAO) received Nelson's grade with conjunctival impression cytology. Proptosis, palpebral fissure width and lagophthalmos were assessed. Ocular surface parameters including proptosis, palpebral fissure width and lagophthalmos did not differ between active and inactive TED patients (P>0.05). Both active and inactive TED patients obtained higher fluorescein staining scores, lower TBUT scores and significantly lower Schirmer test scores than those of controls (P<0.001 for all). Additionally, the TBUT score was significantly lower and the OSDI score significantly higher in the active TED group compared with those in the inactive TED group (P<0.001 for both). Impression cytology revealed a higher proportion of grade 2-3 changes in the active TED group compared with the inactive TED group (P<0.001). Orbital inflammation in TED patients may lead to decreased tear film stability and ocular surface squamous metaplasia.