Macular edema is a sight-threatening symptom in patients with retinal vein occlusion (RVO) and diabetic retinopathy. It is treated by the intravitreal injection of anti-vascular endothelial growth factor agents, but this has a physical burden on patients. Thus, it is important to develop a treatment that can be administered orally. The probiotic Lactobacillus pentosus TJ515 can reduce inflammation by regulating host immunity via its induction of interleukin-10 (IL-10). However, its action on inflammatory diseases of the retina remains unclear. This study aimed to investigate the preventive effects of L. pentosus TJ515 intake on retinal edema using RVO model mice. Occlusion of the retinal vein led to an increase in the thickness of all retinal layers and the inner nuclear layer. Intake of L. pentosus TJ515 for three weeks suppressed the formation of retinal edema versus vehicle and the control strain (L. pentosus JCM1558). The expression of MCP-1 and MCP-3 was increased in RVO model mice but suppressed by the intake of L. pentosus TJ515. F4/80-positive cells (i.e., activated macrophages) were increased in the retinas of RVO model mice but decreased by the intake of L. pentosus TJ515. Therefore, L. pentosus TJ515 suppressed macrophage migration in the retinas. Treatment of mouse bone marrow-derived macrophages (BMDM) with plasma from mice that had ingested L. pentosus TJ515 decreased the mRNA expression of IL-6 and increased the mRNA expression of IL-10. Thus, oral intake of L. pentosus TJ515 can prevent retinal edema through its anti-inflammatory effects on macrophages and inhibiting effects on macrophage migration.