Correlation between Serum Cystatin C Level and Retinal Blood Flow in Patients with Essential Hypertension

Introduction: Hypertension is known to impact the structure and function of the ocular vascular system and is an established risk factor for many eye diseases. This study aimed to detect the blood flow in the optic disc and macula in patients with essential hypertension and to analyze its correlation with serum cystatin C (Cys-C) levels. Methods: This single center, cross-sectional study included 100 patients with primary hypertension without hypertensive retinopathy, who were divided into an experimental group (50 cases, 50 eyes) with elevated serum Cys-C levels and a control group (50 cases, 50 eyes) with normal serum Cys-C. The optic disc and macular vessel density (VD) and vascular perfusion density (PD) were assessed using optical coherence tomography angiography. Data such as the area, perimeter, and circularity of the foveal avascular zone (FAZ) were analyzed. Results: There were statistically significant between-group differences in the VD and PD of the optic disc ( p < 0.05). Spearman correlation analysis of related indicators revealed that serum Cys-C was positively correlated with creatinine, uric acid, and FAZ circularity ( p < 0.05). Furthermore, serum Cys-C was negatively correlated with optic disc VD and PD in some regions ( p < 0.05). Conclusion: In patients with essential hypertension, serum Cys-C is negatively correlated with VD and PD in the inner layer of the optic disc (zone 10).