The retinal vein is a blood vessel located in the eye that carries deoxygenated blood away from the retina, the light-sensitive layer at the back of the eye. It plays a crucial role in maintaining the health of the retina by removing waste products and ensuring proper blood flow. There are several types of retinal veins, including the central retinal vein and the branch retinal veins. Blockages in these veins can lead to conditions such as retinal vein occlusion, which can cause vision problems and require medical attention.