Analysis of Periorbital Soft Tissue in Thyroid Eye Disease

Purpose: To investigate periorbital tissue enlargement in thyroid eye disease (TED) by 3-dimensional CT volumetric analysis. Methods: Twenty-four adult subjects, 16 with TED and 8 controls, were studied. Three-dimensional volumetric calculations were performed on CT imaging of the orbit and face, focusing on the retroorbicularis oculi fat, suborbicularis oculi fat, facial muscles in periorbital region, orbital fat, extraocular muscles, and orbital volume. Analysis was performed using JMP version 12 software. Each measure was compared between the TED and control groups using Wilcoxon rank sum test. Correlations were investigated between periorbital and orbital tissue using the Spearman’s correlation coefficient method. Results: A statistically significant increase in volume was measured in TED patients in the superior and inferior periorbital fat tissue (p = 0.0044, p = 0.047), including the retroorbicularis oculi fat (p = 0.0011), suborbicularis oculi fat (p = 0.0093), and a decrease in facial muscle of superior periorbital region (p = 0.035). Strong positive correlation was noted between the muscles of superior and inferior periorbital region (rs = 0.65; p = 0.0006), and between the suborbicularis oculi fat and retroorbicularis oculi fat (rs = 0.50; p = 0.013). No correlation was observed between orbital and periorbital tissue, except between the orbital fat and the inferior periorbital fat tissue (p = 0.047). Conclusions: Facial fat in the periorbital region is enlarged in TED, with the superior component correlating with orbital fat tissue expansion. These findings may assist in the clinical evaluation and management of disfigurement in TED patients. Superior and inferior periorbital fat is enlarged in thyroid eye disease with the superior periorbital fat expansion correlating with orbital fat expansion.