Quantitative Analysis of Choroidal Thickness and Blood Flow in Thyroid-Associated Ophthalmopathy Using...

To quantitatively analyze choroidal thickness and blood flow in thyroid-associated ophthalmopathy (TAO) using ultra-widefield swept-source OCT angiography (UWF SS-OCTA), and to characterize differences among dysthyroid optic neuropathy (DON), non-DON, and normal eyes.

Retrospective cross-sectional study.

The study included 65 eyes from 35 TAO patients (15 males, 20 females; mean age 51.8 ± 12.6 years), comprising 5 mild, 40 moderate-to-severe, and 20 DON eyes. A control group of 70 eyes from 38 age- and sex-matched healthy subjects (15 males, 23 females; mean age 52.8 ± 14.9 years) was also included.

Ultra-widefield SS-OCTA imaging was performed to capture data sets divided into 9 subfields. Automated segmentation was used to measure structural thickness (whole choroid, large-vessel choroidal layer) and vascular density (choriocapillaris, large-vessel choroidal layer). Parameters were compared between TAO and control eyes, and subgroup analyses were conducted between DON and non-DON eyes.

Choroidal thickness and vascular density in the whole choroid, choriocapillaris, and large-vessel choroidal layer across 9 subfields.

Thyroid-associated ophthalmopathy eyes showed significantly greater whole choroidal thickness (189.9 ± 2.6 μm vs. 182.4 ± 2.3 μm, P < 0.001) and large-vessel choroidal layer thickness (161.4 ± 2.7 μm vs. 149.9 ± 2.3 μm, P < 0.0001) compared with controls, particularly in central and nasal regions. Vascular density was reduced in TAO eyes for the large-vessel choroidal layer (39.86 ± 0.25% vs. 40.54 ± 0.15%, P = 0.014) and showed a nonsignificant decrease in the choriocapillaris (47.57 ± 3.24% vs. 47.89 ± 0.12%, P = 0.067). Subgroup analysis revealed that these differences were primarily driven by DON eyes, whereas non-DON TAO eyes showed no significant changes compared with controls.

Ultra-widefield SS-OCTA effectively identifies choroidal changes in TAO, revealing increased thickness accompanied by reduced vascular density. These findings suggest that choroidal thickening is primarily due to stromal edema rather than vascular engorgement, particularly in DON eyes, highlighting the role of choroidal remodeling in TAO progression.

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