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Let there be light

Eyes are amazing things, even the most sophisticated video cameras can’t compete with them. We can see thousands of colours, the finest details, focus on objects just a few cms or miles away, or walk from a candle lit room into bright sunlight and our eyes automatically adjust. We take this for granted, but sometimes they do need a bit of a repair job.

Eye v camera

What goes wrong?

Things go wrong mostly with the cornea. This is the transparent layer at the front of the eye that lets light pass through the pupil to the lens and the retina. It actually does a bit more than just acting as a transparent window; it also bends or refracts the light, actually much more than the lens does. The lens just does the fine adjustments. If the cornea hasn’t done its bit, the eye will never be able to focus on any object, near or far and the world will always be a blur.

Cornea

Damage to the cornea is the second biggest cause of blindness with around 10 million people being affected. A bacterial infection, Chlamydia trachomatis, blinds almost 5 million people a year alone. If the cornea stops being transparent the eye is said to have a cataract.

Up until now the only really effective treatment for a cataract is a cornea transplant. But this type of transplant can cause a lot of problems:

  • Rejection

Any transplanted organ is seen by the body as a foreign object so the immune system kicks into action to destroy it. This can be avoided by giving the patient anti-rejection drugs and carefully matching the tissue between the donor and patient.

  • Supply

Every cornea transplant needs a cornea donor, but these are in short supply all over the world.

There may be an answer

A team of Swedish scientists have made a synthetic cornea made of collagen. It is a very strong and flexible protein and found in tissues like tendons, ligaments and skin. Collagen injections are often used by cosmetic surgeons to get rid of wrinkles!

Scientists made the cornea using yeast cells genetically implanted with human DNA sequences. It is such a good copy that the body thinks it is its own and doesn’t reject it. This is seriously clever stuff. Even the nerve cells around it grow back so that the whole cornea is regenerated. It actually becomes sensitive to touch and is able to produce tears.

Scientists

So far, ten patients have received the cornea. They were all able to see again and none developed complications. This is very rare in any complex medical treatment.

It is still early days, but fingers crossed. Is it going to be as significant as people hope? Only time will tell. Larger studies will have to done to make sure the results are truly as good as they seem.

The big questions:

How does the eye focus?

What is a cataract?

How can a damaged cornea be repaired?

What are the main problems with organ transplants?

How can these problems be overcome?