We often think that breathing only involves our lungs, bringing in oxygen from the air and sending it through the blood to the rest of the body. And that’s mostly correct. Our cells need oxygen to live and function properly. But here’s something interesting: some parts of the body can actually take in oxygen directly from the air.
Eye is one of those organs. The front of the eye, especially the cornea, gets most of its oxygen directly from the air. Unlike most other body tissues, the cornea doesn’t have blood vessels. If blood were to flow through the front parts of your eye, it would block light and impair your vision. Blood blocks the view, hardly what you want in your line of sight.
The eye is smartly built to provide clear vision while also keeping itself healthy. The cornea is the outer layer of the eye. It’s made of living cells that need oxygen to stay healthy. But since blood can’t reach it, the cornea gets oxygen directly from the air. This is possible because it’s exposed to the air whenever you open or blink your eyes. Oxygen naturally moves from the air into the cells through a process called diffusion, where it flows from where there’s more oxygen (the air) to where there’s less (the cornea).
The eye also has a clear fluid called the aqueous humor, which lies just behind the cornea. This fluid helps deliver oxygen to areas not directly exposed to air, like the back of the cornea and the lens. It’s a smart workaround, use a transparent fluid to get oxygen where it’s needed, without messing up the eye’s optical clarity.
However it’s not just the eyes that take in oxygen this way. Your skin also breathes, sort of. The outer layers of your skin, particularly the top 0.25 to 0.4 millimeters, absorb oxygen directly from the surrounding air. These cells are in constant contact with the atmosphere, so it makes sense that they’d grab some oxygen from it when they can.
The skin also gets oxygen through blood vessels deeper within, but the outermost layers are mostly dependent on direct air contact. A study published in The Journal of Physiology even confirmed that these upper layers rely almost entirely on oxygen from the air, with blood playing only a minor role.
Still, it’s important to note that this kind of air-to-cell oxygen transfer isn’t enough to power the whole body. Our internal organs and deeper tissues are far too isolated from the environment and require the full power of the circulatory system to stay oxygenated.
So while it’s true that most of our oxygen comes via the blood, a few parts of us like the front of the eyes and the top layer of the skin quietly do a bit of breathing on their own.
