AIM: To investigate the patterns of short-term intraocular pressure (IOP) fluctuations and identify the contributing factors following intravitreal injection in patients with retinal vascular diseases. METHODS: Totally 81 patients were enrolled in this case control study. Eyes were categorized into 7 groups, including age-related macular degeneration (AMD), polypoidal choroidal vasculopathy (PCV), idiopathic choroidal neovascularization (CNV), proliferative diabetic retinopathy (PDR), diabetic macular edema (DME), macular edema secondary to branch (BVOME) and central (CVOME) retinal vein occlusion. IOP was measured in all patients using rebound tonometer at 7 preset time points perioperatively. Additionally, based on the administered medication, the eyes were classified into three treatment groups, including dexamethasone intravitreal implant (IVO), intravitreal conbercept (IVC), and intravitreal ranibizumab (IVR). To compare IOP values at various time points across groups, we employed one-way ANOVA, independent sample t-test or χ2 test and multivariate logistic regression analysis. RESULTS: Peak IOP values across all groups were observed at 40s, and 5min after intravitreal injection. Statistical differences in IOP were detected at the 5min among the 7 indication groups (F=2.50, P=0.029). When examing the impact of medications, the IVO group exhibited lower average IOP values at both 40s and 5min compared to the IVC and IVR groups (P<0.001; P=0.007). The IOP values at 40s and 5min were significantly higher in BVOME and CVOME group compared to non-retinal vein occlusion-secondary macular edema (RVOME) group (P<0.001). Multivariate logistic regression analysis further confirmed that IOP measurement at 40s was significantly higher in CVOME group than in non-RVOME group (OR=1.64, 95%CI: 1.09-2.47; P=0.018). CONCLUSION: Needle size plays a crucial role in the transient changes of IOP following intravitreal injection. Before administering intravitreal injection to patients with central retinal vein occlusion, it is essential to exclude any underlysing causes of increased IOP.