Abstract Listings 2026

Purpose

The Barrett index (BI) is a radiological parameter reflecting extraocular muscle enlargement and is widely used in the evaluation of dysthyroid optic neuropathy in thyroid eye disease (TED). However, its relationship with lacrimal gland (LG) prolapse remains unclear. This study aimed to investigate the association between LG prolapse and BI in patients with inactive moderate-to-severe TED.

Methods

In this retrospective study, patients with symmetric inactive moderate-to-severe TED were divided into two groups according to the presence of LG prolapse on orbital computed tomography (CT): patients without prolapse (Group 1, n=40) and patients with prolapse (Group 2, n=14). Healthy individuals served as the control group (Group 3, n=41). Only right eyes were included in the analysis. BI values and LG dimensions were measured and compared among groups. The relationship between BI and the degree of LG prolapse was also evaluated.

Results

There were no significant differences among the groups regarding age or sex (p>0.05). The mean amount of LG prolapse in Group 2 was 11.22±1.48 mm. BI values were significantly higher in both TED groups (Group 1: 49.12±7.6; Group 2: 51.5±12.6) compared with controls (34.24±4.6) (p<0.0001). However, no significant difference was observed between Groups 1 and 2 (p=0.519). Among the groups, Group 2 had the highest LG transverse diameter and the lowest anteroposterior diameter. No significant correlation was found between BI and the degree of LG prolapse in patients with prolapse (p=0.956).

Conclusion

Although BI reflects extraocular muscle enlargement in TED, it does not appear to be associated with LG prolapse. Nevertheless, patients with LG prolapse demonstrated distinct alterations in LG morphology. These findings suggest that LG prolapse may be related to other local anatomical or structural changes independent of extraocular muscle enlargement.

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