It is a condition that causes the front of the eye to mist up. And for those who suffer a failed cornea – the clear front part of the eye – if left untreated, the condition will lead to blindness.
The most common cause is Fuchs’ dystrophy, a degenerative condition that affects older people.
Until recently, the only treatment was a full cornea transplant, an operation that involved 24 stitches in each eye and an 18-month recovery period.
But a remarkable new procedure means a third of the 3,000 British patients who require this surgery every year could be home within hours and healed within weeks.
Partial corneal transplants replace only the innermost layer of the cornea – the endothelium – requiring a single stitch to hold it in place. The operation takes as little as 45 minutes under local anaesthetic, compared with an hour-and-a-half for the full transplant and, because it leaves the eye intact, recovery time is just four weeks.
The cornea helps protect the eye from infection. It also controls the entry of light, bending it on to the lens, which then focuses it on to the retina.
This converts light into images that are sent to the brain for interpretation.
Problems occur due to a malfunction in the normal mechanisms that control the balance of moisture within the corneal tissues. As a result, the cornea takes on too much fluid, swells and becomes hazy.
As the swelling increases, the cornea becomes slightly wrinkled, affecting vision. Pain also becomes a problem because the epithelium, the outermost layer of the cornea that is filled with nerve endings, is also affected.
‘With time there is a deterioration of vision and glare,’ says Martin Leyland, consultant ophthalmic surgeon at the Royal Berkshire Hospital in Reading. ‘Sufferers usually say vision is worse in the morning.’ Corneal grafts are successful in treating Fuchs’ dystrophy and research shows that the condition does not recur after the operation.
In the past full corneal transplant meant cutting through the five layers of tissue that make up the cornea, removing an 8mm circle and using up to 24 stitches to re-attach a donor cornea. The operation leaves the eye permanently weakened.
In the new operation, first a 5mm incision is made in the eye and surgeons create a short tunnel through to the fluid-filled chamber, which separates the cornea from the iris, the coloured part of the eye.
A sliver of endothelium is cut from a donor cornea, which is rolled up, posted into the chamber and unrolled into a flat disc. A bubble of sterile air is injected underneath the graft to float it into place on the underside of the cornea.
It takes 15 minutes for the graft to stick in place, then the air bubble is taken out and the hole in the white of the eye closed up with a stitch. Mr Leyland has been performing the operation since 2008.
Peter Dakin, 69, an acoustic expert from Bridport, Dorset, was referred to Mr Leyland with Fuchs’ dystrophy in 2007, and had his second partial corneal transplant last year.
‘My eyes would mist up sometimes,’ he says. ‘Headlights would flare in my vision, making night-driving impossible. Thankfully the surgery was no worse than a visit to the dentist.
‘My vision started to clear within a few hours, and in two days it was virtually back to normal.’
Source: Daily Mail