My name's James Bull.

I'm a consultant ophthalmic surgeon specialising in cornea

and I'm based at St James' University Hospital in Leeds.

The cornea is the window at the front of the eye

and it's made of three layers.

It's got a delicate skin, then a structural, thicker bit

and then a very delicate lining.

People need corneal transplants for two main reasons,

either because the shape of the cornea is quite poor

or because the lining of the cornea has failed.

Generally those reasons fall into two different age groups.

So the two commonest reasons for doing a corneal transplant

is either because the cornea's become misshapen,

ie the front structural part has become thinned,

and this is a condition called keratoconus.

It tends to affect patients who are in their late teens, early 20s.

The other big group are patients in whom

the delicate lining of the cornea has failed,

and these tend to be elderly patients.

Most of the conditions that affect the cornea come on quite gradually,

so if we talk about keratoconic patients,

as I said, they're young patients

and the first thing they may notice is that they think they need glasses.

The elderly patients, usually they've seen very well for most of their lives.

As the lining of the cornea stops working in these elderly patients,

what they first notice is their vision's a bit blurry first thing in the morning.

What we try and do is just replace the part of the cornea

that isn't working so well,

so this means actually we're trying to do a different operation

for these two largely different groups of patients.

So the elderly patients in whom the lining has failed,

we leave most of their cornea alone

and we just remove the lining that doesn't work so well any more.

We make just a small wound off to the side

and, having prepared a donor sheet of healthy cells,

post that into the eye and use an air bubble

to just stick it into place on the back of the patient's cornea,

so that we've just replaced the unhealthy lining.

With the younger patients with keratoconus,

their lining is fine, there's nothing wrong with it.

The problem is with the shape of the cornea.

So what we do for these patients is split the cornea

so that they keep their healthy lining

and then we provide them with a nice-shaped donor

and we stitch that into place.

With all the kinds of corneal transplant that we do,

in the early period it's important that people don't rub their eye.

We give them a protective shield that they must wear whenever they sleep

or whenever they have a nap.

It's important that in the shower they don't get tap water in their eye.

When it's sticky, just bathing it open with some cooled boiled water.

No eye make-up for the first month.

No swimming for at least the first month.

It's also really important that they don't rub their eye.

Both kinds of corneal transplant are extremely effective

and full thickness transplantation for keratoconus,

we know that at five years over 95 per cent of these patients

will have a healthy, functioning transplant

which is giving them significantly improved vision.