Objective: To investigate the correlation between the thickness of the retinal ganglion cell layer (GCL) measured by optical coherence tomography (OCT) and the severity of white matter hyperintensities (WMH) in cerebral small vessel disease (CSVD). Methods: Thirty-one patients with CSVD were selected and divided into a mild group (21 cases) and a moderate-to-severe group (10 cases) based on the severity of WMH. Additionally, 30 healthy individuals were selected as the control group. All subjects underwent 3.0T cranial MRI and OCT examinations. The severity of WMH was assessed using the Fazekas scale, and the thickness of the GCL in each quadrant, as well as the average and minimum thickness, was measured to analyze their correlation with WMH and their predictive value. Results: Statistically significant differences were observed among the three groups in terms of GCL thickness in the superior nasal, inferior nasal, inferior, and inferior temporal quadrants, as well as the average and minimum thickness (P < 0.05). The average GCL thickness showed a significant negative correlation with the Fazekas score (P < 0.05). Multiple linear regression analysis revealed that the average GCL thickness in the moderate-to-severe WMH group was significantly lower than that in the mild group (P < 0.05), and type 2 diabetes mellitus enhanced this negative correlation. The ROC curve demonstrated that after adjusting for clinical factors, the area under the curve (AUC) for predicting moderate-to-severe WMH using the average GCL thickness reached 0.83. Conclusion: The thickness of the GCL in patients with CSVD is negatively correlated with the severity of WMH, and the average GCL thickness has good predictive value for moderate-to-severe WMH. Meanwhile, OCT, as a non-invasive fundus imaging technique, can provide a new method for the early identification of CSVD and the assessment of white matter lesions.