(1) Introduction: The aim of this study is to assess retinal vessel density (VD) in the superficial capillary plexus layer (SP) and deep capillary plexus layer (DP) in children with chronic heart failure (CHF) in the course of dilated cardiomyopathy (DCM) using optical coherence tomography angiography (OCTA). (2) Methods: Thirty children with CHF due to DCM lasting more than six months, with an enlarged left ventricle and impaired left ventricular systolic function (left ventricular ejection fraction (LVEF) ≤ 55%), were enrolled to have both their eyes assessed for this study. Mean age of the children was 9.9 ± 3.57 years. The control group consisted of an additional 30 children without CHF (mean age 11.27 ± 3.33 years) matched for age and gender against the study group. All participants underwent transthoracic echocardiography to measure LVEF using Simpson method. Blood serum was tested for N-terminal-pro-brain natriuretic peptide (NT-proBNP) marker value. All children underwent OCTA with evaluation of the foveal avascular zone (FAZ), whole superficial vessel density (wsVD), foveal superficial vessel density (fsVD), parafoveal superficial vessel density (psVD), whole deep vessel density (wdVD), foveal deep vessel density (fdVD), parafoveal deep vessel density (pdVD), whole thickness (WT), foveal thickness (FT), and parafoveal thickness (PFT). (3) Results: Retinal VD in SP was significantly lower in children with CHF as compared to the controls. The following SP parameters in the study group were statistically significantly lower than these same measurements for the control group. Details, with study group findings quantified first, include wsVD (46.2% vs. 49.83%, p < 0.05), fsVD (18.07% vs. 24.15%, p < 0.05), and psVD (49.24% vs. 52.51%, p < 0.05). The WT (311.03 micrometers (μm) vs. 323.55 μm, p < 0.05), FT (244.57 μm vs. 256.98 μm, p < 0.05), and PFT (320.63 μm vs. 332.02 μm, p < 0.05). No significant differences in DP retinal VD were found between the two groups. No statistically significant differences in the FAZ were found. The fsVD and FT were correlated with biometry and the age of the study participants. There was a correlation between FAZ and FT (p < 0.001). There were no correlations between retinal VD in both plexuses and refractive error, sex, NT-proBNP, and LVEF. (4) Conclusions: In children with CHF in the course of DCM as compared to the control group, significantly decreased retinal VD in SP was observed. The results of our study indicate that measurements of the OCTA may be a useful diagnostic method in children with chronic heart failure, but it is necessary to conduct further studies in larger groups of participants and long-term observation of these patients.