Is there a link between choroidal and retinal parameters in patients with systemic sclerosis? A prospective study

Purpose: Systemic sclerosis (SSc) is an autoimmune connective tissue disease. It affects choroid causing reduction in its thickness and volume. The aim of this study has been to get a better insight into the pathogenesis of retinal and choroidal involvement in SSc. Methods: This prospective single-center cross-sectional study included 33 patients with SSc and 40 controls. A full ophthalmological and rheumatological assessment was performed. The patients underwent the spectral-domain optical coherence tomography. The thickness of the inner retinal and outer retinal layer (ORL), outer nuclear layer (ONL), retinal pigment epithelium (RPE) was evaluated, as well as the central macular choroidal thickness and choroidal vascularity index (CVI). Results: The inner retinal thickness did not differ. In the outer retina, slight differences were observed in the thickness of the RPE and ORL within the inner temporal subfield, that were thinner in SSc patients, p<0.05. Choroidal parameters differed between the groups (luminal, stromal, and total choroidal areas; central choroidal thickness, p<0.05 for all). Correlations were found in the SSc patients (diffuse cutaneous systemic sclerosis group: the central macular ORL with the CVI rho=0.47, p=0.042; limited cutaneous systemic sclerosis group: the central macular RPE thickness with the total choroidal area rho=-0,7, p=0038, and with the luminal area: rho=- 0,7, p=0036). The univariate regression analyses revealed only few significant associations with low fit of models to the data of the central macular ORL, ONL, RPE with the tested ocular and clinical parameters in the SSc and the controls. Conclusion: It is plausible to assume that, although reduced in the SSc patients, the choroidal blood supply to the outer retina may still be sufficient to maintain its thickness.