A lack of oxygen to the cornea can be a very dangerous thing. But we often don’t think about it, and many of us don’t understand why this is the case.
Our bodies need oxygen to function and we get it from our blood. Of course, the most outer layers of our skin and our eyes get some oxygen from the air around us, but there’s one one site on the body where ALL oxygen comes from outside – our corneas.
That’s because the corneas don’t have blood vessels, so there’s no way to get oxygenated blood to reach them.
Obviously, we don’t want blood vessels in that part of our eye anyway, since it needs to be transparent so we can see.
The very outer surface of the center of our eye is the cornea, and it’s in direct contact with the air. It contains cells that require oxygen to live and keep our eyes functioning properly, which is absorbed directly from the air.
This fact is most relevant to those who wear contact lenses, which block most oxygen to the cornea. This is why we’re told to give our eyes “a break” for a few hours each night and switch to eyeglasses. But not everyone does, and the results can be tragic and irreversible.
If our corneas are severely deprived of oxygen, we may experience watery eyes, burning, swelling, and blurred vision. But some vision loss can be permanent.
Without oxygen to your eye, your cornea may start to accumulate lactic acid and pull in more water, causing edema. Oxygen deprivation may result in the development of corneal hypoxia or corneal cysts, which can compromise our vision.
There is an anterior chamber in the eye that can use diffused oxygen and transport it to the cornea from behind, but in most cases, the best ways to keep your eyes safe is to make sure you don’t have them covered with contacts whenever you’re awake.
Source: “Are there any parts of the human body that get oxygen directly from the air and not from the blood?” — Dr. Christopher S. Baird, West Texas A&M University