The plastic eye implant to replace reading glasses

By Victoria Lambert
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."

Can Boomers Throw Away Their Reading Glasses?

By John Gever, Senior Editor, MedPage Today
Published: October 25, 2010
Reviewed by Robert Jasmer, MD; Associate Clinical Professor of Medicine, University of California, San Francisco and
Dorothy Caputo, MA, RN, BC-ADM, CDE, Nurse Planner

CHICAGO -- With the baby-boom generation now firmly in the age range when near-range vision goes blurry, advances in refractive surgery and implants could allow many of them to do away with reading glasses, researchers said here.

A series of presentations at the American Academy of Ophthalmology's annual meeting indicated that new types of intracorneal implants and LASIK-like procedures show promise for eliminating presbyopia, the progressive deterioration of near vision that afflicts virtually everyone older than 45.

Among the innovations highlighted at the meeting: a doughnut-shaped corrective lens inserted under the cornea; a thin disk that restricts the pupillary opening, improving depth of focus in the same way as a pinhole camera; and a noninvasive, implant-free laser procedure that cuts concentric rings in the corneal stroma to alter its refractive power.
None of these are yet approved by the FDA.

At a press briefing, Gustavo Tamayo, MD, of the Bogota Laser Refractive Institute in Bogota, Colombia, described in broad strokes the procedures that are available in South America and Europe, which can target the cornea, the sclera, the anterior chamber, or the lens itself.

Many procedures are owned and developed by U.S. companies, though, and eventual FDA approval is expected. Several of these were the focus of scientific presentations at the AAO meeting, including a report from one U.S. clinical trial.

Intracorneal lens

Ioannis Pallikaris, MD, of the University of Crete in Greece, discussed a recent one-year clinical study with an intracorneal bifocal lens called Flexivue.

The implant has a hole in the center, not as part of its refractive design but to aid in centering it over the pupil.

Session discussant Karl Stonecipher, MD, of TLC Laser Eye Center in Greensboro, N.C., noted that "centration" is a major issue for all types of refractive alteration intended to assist the natural lens -- vision will be imperfect and sometimes worse than before if the corrective intervention is even slightly out of alignment with the lens.

Pallikaris said the lens is 20 microns thick and 3 mm in diameter and is inserted into a pocket created within the stroma with a femtosecond laser.

He reported data on 15 patients with a mean age of 51 receiving the implant -- one per patient in the nondominant eye.

Mean baseline near-vision acuity was 20/50. Within one week of the implant, it improved to 20/32, settling at 20/25 by the third month where it remained for the full year of follow-up in the study.

The bifocal lens also provides a focal point for distance vision, to compensate for the impairment of distance vision that otherwise would result from an anti-presbyopic change in corneal refraction.

In the implanted eye, mean uncorrected distance-vision acuity dropped from 20/20 at baseline to 20/40 during the first month, and then recovered to 20/30 at six months.

Pallikaris noted, though, that uncorrected binocular distance vision remained perfect throughout the entire study, because the artificial lens is placed only in the nondominant eye.

He reported that all of the patients reported their uncorrected near vision after the procedure was excellent or good, and 92% had stopped all use of reading glasses.

Light-restricting disk

Another approach alters the eye's optics not with a lens but with a small disk that reduces the effective pupillary diameter to create a pinhole effect.

Daniel Durrie, MD, of the University of Kansas Medical Center and DurrieVision in Overland Park, Kan., explained that the concept is similar to the F-stop setting of a camera that opens and closes the lens aperture.

A small aperture setting increases the so-called depth of field, such that objects both near and far are in focus. Consequently, this product does not impair distance vision and could actually improve it.

He is leading U.S. testing of the implant, called AcuFocus, which in its current version (the third to date) cuts the effective pupillary diameter from about 4 mm under indoor artificial light to 1.6 mm. The reduction in light transmission is 95%.

As with the Flexivue lens, it's implanted in only one eye. Durrie told MedPage Today that patients do notice that the reduction in light transmission, but it doesn't diminish their overall binocular vision.

The disk also contains 8,400 tiny holes, 5 to 11 microns each, to allow ocular fluids to pass back and forth across the implant to anterior tissues.

Durrie said the implant can be placed under a corneal flap or in a pocket. He said he prefers a flap because it eases positioning and removal, if necessary.

He reported three-year follow-up data from 163 patients receiving two earlier versions of the implant, which were somewhat thicker, with a larger aperture (restricting light by 89% and 93%) and fewer, larger holes for fluid porosity.

Unlike the Flexivue lens and other approaches that change the cornea's refractive properties, the Acufocus lens had almost no impact on the distance acuity, Durrie said.

Among 44 patients receiving the product's first version, the average uncorrected near-vision grade was J2 and mean uncorrected distance vision was 20/25.

The second version, which had a smaller aperture than the first, produced mean uncorrected distance vision of 20/20 and an uncorrected near-vision grade of J1 in 119 patients.

Durrie said a U.S. clinical trial with the third version is now under way in 504 patients. The product is already marketed in Europe and Asia, he said.

He indicated that the disk, at least currently, is not color-matched to the patient's iris and therefore is visible in some patients, especially those with blue eyes. He indicated that one patient didn't like the cosmetic effect and demanded the implant's removal.

Laser-etched rings

A third approach is somewhat similar to laser keratotomy, except that it uses a femtosecond laser to make concentric circular cuts in the stroma.

Mike Holzer, MD, of the University of Heidelberg in Germany, said that procedure takes just 20 seconds once everything is set up.

The arrangement of the rings and the stromal depth can be adjusted to achieve the desired refractive correction, he said.

He also noted that it does not involve any incisions in eye's surface, virtually eliminating infection risk.

He described results in 25 patients with a mean age of 56 treated in mid-2008, with up to 24 months of follow-up available.

At baseline, the patients had uncorrected near vision of 0.70 logMAR units (SD 0.16), equivalent to about 20/100.

Three months after treatment, their mean near-vision acuity had improved to 0.20 logMAR units, or about 20/30, Holzer said.

At 12 months, the mean value worsened slightly to 0.30 logMAR, but among patients evaluable at 18 and 24 months, it was back to 0.20.

Most patients evaluated at 24 months had gained five to six lines of uncorrected near acuity on a standard chart relative to baseline, Holzer said, allowing them to read newspapers held at a normal distance without reading glasses.

He noted that the procedure does induce a degree of myopia for distance vision. "The ideal patient should be a little bit hyperopic [at baseline]," he said.

However, there was no diminution of middle-distance acuity, he added.

At the press briefing, Richard Lindstrom, MD, of Minnesota Eye Consultants in Bloomington, Minn., discussed still other approaches involving the lens -- either replacing it entirely with a multifocal synthetic lens as part of cataract surgery, or implanting a so-called phakic intraocular lens that rests on top of the natural lens.

These also are largely development-stage products in the U.S., though they are marketed elsewhere in the world.

Lindstrom said a major consideration for all these treatments is the limited reimbursement available from third-party payers.

He noted that Medicare has ruled out payment for surgeries and implants for acuity problems that could be corrected with glasses, and private insurers have largely followed suit.

Consequently, at least for the near future, baby boomers facing combination problems such as cataracts, myopia, and presbyopia will have to pay for these do-it-all procedures out of pocket.

Lindstrom said such patients therefore have a decision to make, regarding how much they're willing to pay for uncorrected perfect vision versus settling for cheaper procedures that correct some problems but still leave them needing glasses or contact lenses for driving or reading restaurant menus.