There are some parts of the eye that can be donated to another person, and there are some parts that can be replaced with artificial versions. But why can’t entire eyeballs and eye systems be transplanted?

Complexity

Right after the brain, the eyes are the most complex organs in the human body. These eyes are made up of intricate blood vessels, nerves, muscles and tissues.

It also takes a split second for the eye to turn light into an image and send it to the brain, one of the most impressive feats of the human body. Because of how complex this organ is, it’s not currently possible to transplant an entirely new eye.

The optic nerve

The biggest complexity in the eye (and the main reason why we can’t transplant entire eye systems) is the optic nerve. This two-inch long nerve is made up of about one million tiny fibers that connect from the back of each eye to the brain.

The optic nerves send electrical signals to the brain, making sight possible. Currently, doctors and surgeons don’t have the technology to detach and reattach these nerves to the brain—that are just too many small (and important) parts.

Transplant issues

There are other complications that come with trying to transplant entire eyes. Like with any transplant surgery, doctors have to make sure the donor organ will have adequate blood flow, good nerve function, and won’t be attacked by the body’s immune system.

What parts can be transplanted?

There are certain parts of the eye that can be transplanted from donor eyes to living humans. Surgeons can transplant:

(Want to become an eye donor? Register here.)

Eye transplants will be possible

Not all hope is lost. Currently, there’s a team of surgeons in Pittsburgh who hope to be able to transplant an entire eye by 2026! Thanks to advances in technology, new medicinal drugs, and trials in (safe) animal experiments, this team is close to taking a healthy, intact eye from a donor and implanting it into a receiver.

Originally posted 2017-02-27 14:29:59.