Abstract:  Objective To study pathological changes of conjunctiva, extraocular muscle and pulley of thyroid associated ophthalmopathy (TAO). Design Experiment study. Participants The TAO group consisted of 16 TAO patients who need surgical correction of strabismus. There were 8 males and 8 females with an age range of 32 to 65 years (mean 50.3±6.7 years); the control group consisted of 12 non-TAO patients with concomitant strabismus. There were 6 males and 6 females with an age range of 6 to 52 years (mean 28.8±7.4 years). Methods The samples of conjunctivas, extraocular muscles and pulleys were collected from those TAO patients who need surgical correction, including 16 conjunctivas, 12 extraocular muscles, and 9 pulleys. And 12 conjunctivas, 8 extraocular muscles, and 8 pulleys were obtained from the control group. Operation findings，HE staining, special staining and immunohistochemical staining were used to observe the pathologic changes of the samples from the two groups. Main Outcome Measures Pathological changes of conjunctiva, extraocular muscle and pulley. Results Comparing with the control group, 14 conjunctival epitheliums were thickened, 2 conjunctival epitheliums were atrophy, 16 conjunctival samples showed substantia proprias fibrosis, tissues disturbanced, inflammatory cellular infiltration around the vascular walls in the TAO group；10 extraocular muscle fibers were thickened, 2 extraocular muscle fibers were atrophied，and all 12 extraocular muscles fibers showed various degrees of ruptured fibrosis, significant collagen fibers proliferation, vacuolization in the TAO group; 9 pulley muscle fibers were ruptured, tissues disturbanced, elastic fibers ruptured, collagen fibers proliferation significantly, vacuolization in the TAO group. Conclusion In TAO group, not only the extraocular muscles, but the connective tissue, as well as conjunctivas, probably experienced similar process from the degenerative inflammatory response to fibrosis, which result into various clinical manifestations of the eye. (Ophthalmol CHN, 2014, 23: 130-134)

Key words: thyroid-associated ophthalmopathy/pathology, conjunctiva, extraocular muscle, pulley