Association of the Pan-Immune Inflammation Value with Retinal Vein Occlusion: A Retrospective Case-Control Study

Background/Objectives: Retinal vein occlusion (RVO) is a common retinal vascular disease involving local and systemic inflammation. The pan-immune inflammation value (PIV) integrates multiple circulating blood cells and can serve as an indirect indicator of systemic inflammatory activity. This study evaluated the association between PIV and RVO, comparing its discriminatory performance with other indices. Methods: This retrospective case–control study included 120 participants (60 RVO patients and 60 controls). Complete blood count (CBC) parameters were recorded, and the monocyte-to-lymphocyte ratio (MLR), platelet-to-lymphocyte ratio (PLR), neutrophil-to-lymphocyte ratio (NLR), systemic inflammation response index (SIRI), and PIV were calculated. Receiver operating characteristic (ROC) curve analysis evaluated discrimination between RVO and controls, and binary logistic regression identified factors associated with RVO. Results: Age, gender, and diabetes prevalence were similar between groups, whereas hypertension was significantly more prevalent in the RVO group (p = 0.035). Neutrophil counts, NLR, SIRI, and PIV were significantly higher in patients with RVO after FDR correction (<0.003, <0.003, =0.004, and <0.003, respectively). Areas under the ROC curve for SIRI, PIV, and NLR were 0.664, 0.678, and 0.738, respectively. In univariable logistic regression, elevated PIV was significantly associated with RVO (OR: 3.76, 95% CI: 1.7–8.2, p < 0.001). After adjustment for age, gender, hypertension, diabetes mellitus, and smoking status, continuous PIV was associated with RVO (adjusted OR per 100-unit increase: 1.41; 95% CI: 1.08–1.83; p = 0.010). Conclusions: PIV was associated with RVO after adjustment for clinical covariates, whereas its association was not statistically significant in the model containing other CBC-derived indices.