Purpose <p>To evaluate the diagnostic utility of the Prognostic Nutritional Index and Controlling Nutritional Status score in patients with retinal vein occlusion.</p> Methods <p>In this retrospective case–control study, 55 patients diagnosed with retinal vein occlusion between Jan 2019 and May 2024 and 110 healthy controls were examined. Demographic data, systemic comorbidities, laboratory parameters, the Prognostic Nutritional Index and the Controlling Nutritional Status score were compared between groups. Binary logistic regression analysis was used to identify independent predictors of retinal vein occlusion; receiver operating characteristic curve analysis was used to evaluate the discriminative performance of Prognostic Nutritional Index and Controlling Nutritional Status score.</p> Results <p>The mean age (<i>p</i> = 0.311), and gender distribution (<i>p</i> = 0.226) were similar in retinal vein occlusion and control groups. Hypertension was more prevalent in retinal vein occlusion group (89.1% vs. 60.9%, <i>p</i> &lt; 0.001). Mean Prognostic Nutritional Index (45.62 ± 1.52 vs. 45.59 ± 2.41, <i>p</i> = 0.557) and median Controlling Nutritional Status scores (0 vs. 0, <i>p</i> = 0.129) were similar between groups. In multivariate logistic regression analysis, only hypertension independently predicted retinal vein occlusion (OR = 5.12; <i>p</i> = 0.001). Prognostic Nutritional Index demonstrated poor discrimination (AUC = 0.528; <i>p</i> = 0.557) for retinal vein occlusion.</p> Conclusions <p>Prognostic Nutritional Index and Controlling Nutritional Status score, which are valuable prognostic biomarkers in some chronic systemic and ophthalmologic diseases, could not distinguish retinal vein occlusion cases from controls. Hypertension remains the principal modifiable risk factor for retinal vein occlusion.</p>