the

Repairing the cornea: let there be sight

how do we keep our vision clear and what

happens if that view starts to cloud

over our window onto the world is the

cornea which lets light into our eyes to

keep the cornea in perfect condition a

fine layer of cells on its surface are

constantly replaced flowing in from a

region called the limbus outside the

limbus a thick layer of cells called the

conjunctiva protects the rest of our eye

the limbus acts as a barrier between the

cornea and the conjunctiva but if it

gets damaged the conjunctiva can start

to grow across the cornea clouding the

window and cutting out the light

eyedrops or vitamin A supplements can

help speed up healing from minor damage

but if the damage is more severe more

drastic action might be necessary

doctors can take some of the patients

healthy limbus and transplant it but

take too much and they risk causing the

same problem at the donor site instead

they can transplant cells or even entire

corneas from other people corneal

transplants are well understood

procedures and they bring the whole

package

Lamia linda's in all but the risk of the

body rejecting the transplant is high

and the drugs needed to make the process

work have dangerous side effects if the

patient has a small amount of healthy

limbers left doctors can still just take

a chunk and amplify the cells in the lab

before transplanting them back into the

eye that way there's no rejection and

far fewer cells are needed sounds good

but it requires specialist equipment and

the patient still might not have enough

healthy limbus left to work with

in these cases scientists can repair the

damage using cells where a patient's

mouth that these aren't totally

transparent and so cloud the cornea

better than nothing

but far from ideal in the most severe

cases doctors can insert a prosthetic

cornea but they try to avoid this as it

brings with it a risk of infection and

of a dangerous buildup of pressure

behind the prosthesis

no one knows which of these treatments

is most successful as no one studied it

instead treatment plans often just based

on each doctors preference or the

facilities at the Medical Center in the

future researchers would like to grow

bespoke corneas by engineering the

patient's own stem cells these would be

complete like a transplant but they

wouldn't be rejected they'd be a perfect

fit for the patient's eye and doctors

wouldn't need to use any limbal cells to

build them however research into these

sorts of treatments is still in the very

early stages and for now it remains way

out of sight

[Music]