Oxygen transport in the eye. The cornea is a unique, living tissue and is a transparent window through which light enters the eye to be focused on the retina, thus forming the images of our surroundings and enabling sight. When the eye is open, it receives all of its oxygen requirements from the surrounding air. When the eye is closed, it is cut off from the O2 source in the air. There is a rich microvascular bed (well perfused with high vascular density on the inner surface of the eyelid) that supplies the cornea with oxygen and possibly other nutrients. What transport process (diffusion or convective) plays a major role in the transport of nutrients via these layer of tissue cells to the cornea? Layer Thickness um Diffusion Coefficient Velocity of transport (cm/s) um/min Epithelium 3.8 E-10 8 Stroma 450 3.8 E-10 0.67 Endothelium 10 3.8 E-4 106.8 40