8:00AM BST 11 Sep 2011
The Telegraph
It is one of the signs of reaching middle-age: the need to wear reading glasses.An estimated 23 million Britons suffer from presbyopia, or age-related longsightedness.Now a revolutionary new treatment, involving an operation to insert a plastic implant into the eye, could allow millions to abandon their spectacles.
The procedure will be available to private patients in Britain for the first time from tomorrow. Its promoters predict up to four million Britons – one in six of those who now use reading glasses – will have the operation over the next decade.
Independent experts say that the early signs from trials are promising, although one side effect is a worsening of night vision and there is not yet evidence of what long-term effect the operation might have.
In the procedure, a laser is used to make an incision in the cornea – the front lens of the eye – so that an inlay thinner than a red blood cell can be inserted by hand.
Looking like a flattened black polo mint, and smaller than a contact lens, the implant sits around the iris and pupil.
Working like a pinhole camera, it reduces the amount of light allowed through the pupil to reach the retina, the part of the eye where rays of light are turned into images.
By allowing through central beams, which produce the sharpest images, and blocking out those on our outer range of vision, which are useful for seeing in dark light but do not produce clear pictures, the implant can restore the perfect vision most of us were born with.
"Finding a treatment for presbyopia is important," said ophthalmologist Dr David Allamby, who specialises in the condition.
"As we age, the crystalline lens, which sits behind the cornea and acts like a zoom, stiffens from a squashy gel-like substance to a fixed structure. This makes it harder for eye muscles to squeeze it into shape, in order to get a clear image.
"Most over 45s will know that feeling: suddenly, struggling to read menus or maps. We squint at text messages, but our longer sight for driving, say, remains good.
"By the age of 50, 90 per cent of your lens flexibility is lost. The only people who will still read easily are those who were born short-sighted, but who already use glasses for distance work."
He added: "This is like granting immunity from the ageing process – at least for your eyes."
The procedure, called Z Kamra, was developed at a cost of $70 million (£44 million) in California where it is still in clinical trials. It has been available in Japan and parts of Europe since last year, with 6,000 treatments carried out so far.
Theresa Ferguson, 53, a health worker from south east London, was the first in the UK to have the treatment.
The mother-of-three said: "I had brilliant eyesight until I was 45. Then I began struggling with newspapers; I need to read small print on medical forms for work so I tried reading glasses and then varifocals."
A specialist suggested she might join a Z Kamra trial instead, and she had the surgery last month.
"I was nervous," she admitted. "But it was painless, although uncomfortable. It took 15 minutes."
During the procedure, the eye is anaesthetised by drops and held open to prevent movement.
Dr Allamby said: "I use a laser to even out the corneal surface and create a flap then, using high magnification tools, insert the implant by hand. The flap heals without stitches, but we give steroid drops for up to eight weeks to prevent rejection."
Mrs Ferguson's eyes were blurry and sore on the day of treatment, but the following morning she awoke with perfect vision. "I read a text message in bed without even thinking," she said. "It was amazing."
Dr Allamby said: "We believe this will be permanent as long as your near sight remains stable.
"The Kamra inlay is made of Polyvinylidene Fluoride (PVDF), a pure thermoplastic fluoropolymer, used for years for replacement cataracts, known to be safe and inert in the body."
Early trial patients have had implants, studded with 8,400 perforations to allow nutrients to pass through, for six years with no reported problems.
Those with a high degree of short or long sight, such as prescriptions of minus six or plus three, or those over 70 might not be suitable for the treatment as their cataracts may be close to needing replacement.
The procedure costs £2,800 for one eye but 90 per cent of patients will need both eyes treating for £4,600. Equivalent laser surgery would cost £4,000.
Dr Larry Benjamin, an eye surgeon at Stoke Mandeville Hospital in Buckinghamshire and chair of the Royal Society of Ophthalmologists education committee, was cautious.
He said: "This is an interesting concept. But it won't suit everyone and I imagine certain professionals such as pilots, where night vision is important, would not be allowed it, but the research so far shows it works reasonably well.
"However, I would like to see more follow-up data in terms of complications and visual symptoms."
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