Evaluation of the choroidal vascularity index and choroidal thickness in patients with systemic sclerosis

Purpose: To evaluate the choroidal structural components using central macular thickness (CMT), choroidal thickness (CT) and the choroidal vascular index (CVI) and compare the results between patients with systemic sclerosis (SSc), causing both fibrotic and angiopathic changes in tissues and healthy controls. Methods: This prospective comparative study evaluated 22 patients with SSc (SSc group). The patients' choroidal thickness, CVI and choroidal area (CA) were compared with 21 healthy controls (control group). The patients' nailfold videocapillaroscopy (NVC) and modified Rodnan skin score (mRss) were evaluated by expert rheumatologists. In addition, the relationships between choroidal findings and NVC and mRss were assessed. Results: The central macular thickness in the SSc and control groups was 269.47 ± 26.78 µm and 261.19 ± 17.09 µm, respectively (p = 0.093). The subfoveal choroidal thickness was 295.38 ± 33.70 μm and 322.16 ± 70.24 μm, respectively (p = 0.026); the temporal choroidal thickness was 246.77 ± 21.83 μm and 265.26 ± 52.34 μm, respectively (p = 0.034); and the nasal choroidal thickness was 135.36 ± 28.10 μm and 158.88 ± 49.16 μm, respectively (p = 0.008). Total CA of 1.5 mm region centered on the fovea was 0.49 ± 0.08 mm2 and 0.55 ± 0.09 mm2, respectively (p = 0.002); total CVI of 1.5 mm region centered on the fovea was 63.66% ± 1.23 and 64.90% ± 1.07, respectively (p < 0.001); total CA of 6 mm region centered on the fovea was 1.61 ± 0.22 mm2 and 1.80 ± 0.33 mm2, respectively (p = 0.003); the total CVI of 6 mm region centered on the fovea was 63.85% ± 1.16 and 64.87% ± 1.12, respectively (p < 0.001). There was no correlation between mRss score and Raynaud severity and CMT, CVI and CTs; however, there was a positive correlation between the mRss and the Raynaud severity (p = 0.0004, r = 0.507). Conclusion: This study found that choroidal thickness and CVI decreased in SSc patients. A decrease in CVI may be an indicator of damage, especially in luminal structures.