TEENAGE siblings who underwent a new sight-saving procedure to halt a progressive eye disease have called for the treatment to be made available on the NHS.

Plymstock School students Alex and Laura Hook, aged 17 and 14, have keratoconus which causes the cornea to thin and bulge into the shape of a cone.

Patients in the advanced stages often require a cornea transplant operation to improve severely blurred sight.

A private hospital in Plymouth is the only facility in the South West providing an innovative ultra violet light treatment which toughens the cornea.

It can stop sight worsening and make surgery unnecessary, but costs £1,000 per eye.

A-level student Alex, who underwent the one-hour procedure on his left eye, said: "I got keratoconus at about the same age as my dad first did.

"He had to have a cornea transplant about five years ago because his sight got so bad. It was a big operation and he took about a year to recover.

"With my treatment, it was slightly painful afterwards but other than that it was quick and now I know my sight is safe. I don't have to worry about it anymore.

"I'd like to see it available on the NHS."

Alex received the treatment at Nuffield Health Plymouth Hospital in November.

His consultant Mr Nabil Habib said, as the condition was caught in the early stages, Alex was unlikely to need further treatment in his left eye.

Laura, who was diagnosed with the condition when she was nine years old, has not been so lucky.

She has undergone the procedure to prevent the blurred sight in her left eye from worsening further.

But she is likely to require a cornea transplant in her right eye, which has deteriorated too far for the treatment to be effective.

It means she has difficulty reading and writing and receives learning support at school. She also needs a constant supply of new contact lenses, as her eyes continually change shape.

She said: "I'm really happy for Alex because his eyes won't get any worse like mine have. If the treatment had been available a few years ago I could have had it on my worse eye.

"I really would like to see the procedure on the NHS. Then there would be no need to spend money on transplants and contact lenses."

Their father Kevin Hook, 49, a quality systems manager at a local manufacturing firm, described the treatment as "amazing".

He said: "This condition doesn't correct itself, it just gets worse and the procedure is something the NHS should latch on to."

He thanked the Nuffield team for his family's care.

Mr Habib, consultant opthalmic and corneal transplant surgeon, started treating patients with the new procedure in October last year.

Called 'collagen cross linking', it involves treating the eye with riboflavin (vitamin B) before exposing it to ultra violet light, which toughens the cornea and prevents it from distorting further.

The Nuffield hospital in Plymouth is the only place offering the treatment in the South West, he said.

Mr Habib said: "It's a revolutionary treatment. It stops the condition from progressing for at least a decade.

"The condition seems to progress more in younger people. If we can catch it early and delay it for 10 years then patients may not need further treatment."

About 15 patients have been treated so far and results have so far been 'very good', said Mr Habib, in line with successful clinical studies abroad.

Keratoconus affects one in every 2,000 people. About 20 per cent of sufferers end up needing a cornea transplant.