## 4 Discussion  
Data from recent studies suggest that 48% of RVO is connected with NTH, 20% with HLD, and 5% with DM [5; 34]. Whereas HTN and glaucoma are commonly indicated as risk factors for CRVO, the influence of other general diseases on CRVO appearance is unclear [35; 36; 37; 38; 39; 40; 41; 42; 43]. Some studies have shown DM to be an important risk factor of CRVO, whereas others were unable to find a significant correlation between DM and CRVO [36; 37; 38; 39; 43; 44; 14]. The Eye Disease Case-Control Study Group assessed the risk factors for both central and branch retinal vein occlusion in a large multicenter study. They found an increased risk of BRVO in patients with a history of cardiovascular disease or systemic hypertension, but not in patients with DM [45]. They noted a cardiovascular risk profile for patients with BRVO and indicated that 50% of them may be attributable to hypertension. On the other hand, the authors of The Eye Disease Case-control Study Group confirmed an increased risk of CRVO in patients with DM apart from other diseases, such as systemic hypertension and open-angle glaucoma. However, they emphasized that the history of treatment of DM and higher blood glucose levels, as well as cardiovascular disease, electrocardiographic abnormalities, higher alpha-globulin levels, and lower albumin-globulin ratios, were associated with an increased risk only for the ischemic form of CRVO [37]. [PERSON] et al. assessed the correlation between the components of the metabolic syndrome (HTN, DM, and HLD) individually and in combination with the risk of CRVO. They concluded that there was no increased risk of CRVO in the case of patients with DM alone (no HTN or HLD). When all three metabolic syndrome components were present, the risk of developing CRVO increased to 58% [13]. The risk of CRVO was connected with the severity of DM in individuals. For those with end-organ damage from DM, the risk of CRVO increased to 53% compared to those without DM. In the case of those without end-organ damage, there was not a noticeable risk for CRVO. Similar conclusions were drawn by [PERSON] et al. with respect to BRVO [10]. Although there was no association between DM without end-organ damage (\"uncomplicated\" cases of DM) and BRVO (\(p\) = 0.2), subjects with end-organ damage from DM (\"complicated\" cases) had a 36% increased hazard of developing BRVO (\(p\) < 0.0001) compared to those without DM. These studies may explain the differences between the final conclusions found in the literature. Authors have suggested that, when studying individuals with various stages of diabetes, it is possible that patients with uncomplicated DM mask the significant effect of complicated DM on CRVO risk. Meanwhile, a recent nationwide, retrospective, matched cohort study, which included 240,761 DM patients, established that individuals with new-onset DM have a significantly increased risk of RVO [46]. These results seem to confirm an increasing association between DM and RVO over time. In relation to general risk factors, our study confirmed an important role of hypertension in developing RVO. HTN was the most common risk factor in both groups of RVO, although HTN was significantly more frequent in the BRVO group (in 81.8% in BRVO compared to 58.3% in CRVO group). These findings agreed with data from other authors [14; 38; 45]. Similar to data from the literature, in this study, hyperlipidemia was noted in approximately 20% of RVO cases (16.7% and 27.3% in the CRVO and BRVO groups, respectively) [14; 37; 34]. However, the incidence of DM in both BRVO and CRVO groups differed from other publications [34]. In their meta-analysis, [PERSON] et al. noted that DM was slightly more prevalent among the 2877 cases with any form of RVO than the 13,225 unaffected controls, and the PAR% for DM among individuals with any form of RVO