Increased choroidal stromal area in patients with active Graves' ophthalmopathy based on binarisation method of optical coherence tomographic images.

Objective: To investigate the change in choroidal components of patients with Graves' ophthalmopathy (GO) with different degrees of disease activity and severity by using the image binarisation method of optical coherence tomography (OCT).

Methods: This cross-sectional study included 151 eyes of 90 patients with GO. Patients were grouped according to the clinical activity score (CAS) and disease severity. Total choroidal area (TCA), luminal area, stromal area (SA) and choroidal vascularity index (CVI) were acquired by image binarisation of the OCT. Ocular parameters between groups were compared using generalised estimating equations, accounting for intereye correlation and adjusting for relevant factors.

Results: As for the included eyes, 104 eyes were inactive GO and 47 eyes were active GO. Local choroidal thicknesses were thicker in active GO than in inactive GO. TCA and SA were significantly larger in active GO than in inactive GO group (3.44±0.91 mm² vs 3.14±0.88 mm², p=0.046; 1.16 (1.03-1.50) mm² vs 1.10 (0.96-1.27) mm², p=0.002, respectively). CAS was positively correlated with TCA (r=0.171, p=0.036) and SA (r=0.172, p=0.035), and negatively associated with CVI (r=-0.174, p=0.032). In multiple regression models, age, diopter and intraocular pressure (IOP) exhibited significant correlations with the SA (β=-0.006, p=0.010; β=0.076, p<0.001; β=0.015, p=0.010, respectively).

Conclusions: Thickened choroid was observed in active GO compared with inactive GO. The proportional increase of SA was augmented as the disease activity progressed. Age, diopter and IOP were independent factors that affected choroidal area and components in patients with GO. Multicentre prospective cohort studies with a large sample size are still needed.