Lacrimal Gland Fibrosis in Patients With Moderate-to-Severe Thyroid Eye Disease

Purpose: To evaluate the elasticity and size of the lacrimal gland (LG) in patients with moderate-to-severe thyroid eye disease (TED) using strain ultrasound elastography and to compare these results with those of healthy subjects. Methods: This prospective, comparative case series included the right eyes of 26 patients with bilateral inactive moderate-to-severe TED and 49 healthy subjects, who served as the control group. Schirmer test, tear breakup time, ocular surface disease index, and corneal staining were assessed in both groups. The anteroposterior and transverse diameters of the LG were measured, and the strain index of the LG was calculated as the ratio of the LG to orbital fat tissue. Results: The anteroposterior diameter of the LG was 4.18 ± 1.02 mm in the TED group and 5.32 ± 1.54 mm in the control group ( p = 0.002). The transverse diameter of the LG was 7.48 ± 1.63 mm in the TED group and 9.46 ± 2.61 mm in the control group ( p = 0.001). The strain index of the LG was 3.91 ± 1.40 in the TED group and 1.03 ± 0.62 in the control group ( p < 0.001). Schirmer test and tear breakup time values were significantly lower, while ocular surface disease index scores and corneal staining scores were significantly higher in the TED group compared with the control group. Discussion: Strain ultrasound elastography revealed that the LGs of TED patients were stiffer than those of healthy subjects. Additionally, both the anteroposterior and transverse diameters of the LG were smaller in the TED group. These findings suggest that increased LG stiffness and reduced size may contribute to dry eye symptoms.