Impact of Axial Orbital Depth on Extraocular Muscle Diameter Changes Following Retrobulbar Glucocorticoid Injection in Graves Ophthalmopathy: A Retrospective Cohort Study.

OBJECTIVE

The objective of this study was to explore the impact of the bony orbit on the alteration of extraocular muscle diameters (EMDs) following retrobulbar injection of glucocorticoids (GCs) in patients with Graves ophthalmopathy (GO), which is a common therapeutic approach.

METHODS

Retrospective collection and analysis of data were conducted on GO patients who underwent retrobulbar GC injection. Measurements of bony orbital dimensions before and after injection were acquired through orbital computed tomography. Univariate and multifactorial logistic regression analyses were employed to identify bony orbital parameters as potential risk factors contributing to post-treatment EMD changes in GO patients.

RESULTS

A total of 60 GO patients with 102 eyes were included, with a male-to-female ratio of 1.07:1.00 and a mean age of 49.28 ± 9.40 years. After retrobulbar GC injection, EMDs decreased in size in 36 eyes, while remaining unchanged or increased in 66 eyes. An axial orbital depth threshold effect on EMD alteration was observed. When axial orbital depth was below 41.28 mm, there was no significant correlation between EMD changes and axial orbital depth (OR: 1.09, 95% CI: 0.75-1.57, P = 0.6644). However, a protective effect was evident when axial orbital depth exceeded 41.28 mm (OR: 0.41, 95% CI: 0.18-0.90, P = 0.0260). For every 1-unit increment in axial orbital depth, the risk of non-decrease in EMD decreased by 59% (95% CI: 0.18-0.99, P = 0.00260).

CONCLUSION

The alteration of EMDs following retrobulbar GC injection in GO patients is associated with axial orbital depth.