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Saturday, 13 April, 2002, 23:24 GMT 00:24 UK
Magnetic fluid 'could save sight'
The retina is located at the back of the eye, BBC
The retina is located at the back of the eye
Blindness could be prevented in people with damaged retinas using magnetic fluids, researchers say.

US scientists are developing the fluids, which they say could be injected to repair torn or detached retinas.

But a UK eye expert says he does not think the technique will be useful in humans.

The retina is the thin, light-sensitive layer of tissue at the back of the eye. If it becomes detached or torn because of injury or disease, vision is impaired. If the damage is not repaired, it can lead to blindness.


If it works, it will be wonderful

J P Dailey, researcher
In the UK around one in 10,000 each year suffer retinal detachment.

Silicone fluid is currently used to push damaged retinas back into place, but the researchers say a magnetised version would make it easier to repair the problem.

They add the method would also be more precise because it could allow the fluid to be moved, by using an external magnet to direct it, to areas of the eye that are hard to reach.

So far, tests have only been carried out in laboratories, but the team from Virginia Tech, Blacksburg, Virginia - which has been developing the material for 10 years - is hoping to carry out studies using animals within a year, and human studies soon after.

Innovation

In the technique, minute particles of cobalt or magnetite are enmeshed in a silicone-based fluid and exposed to the external magnetic field.

Cobalt can be toxic, so the research team is focussing on magnetite, an iron-based material instead.

It is also looking at ways to ensure particles in the fluids do not lose their magnetism over time so they can be implanted permanently.

Magnetic fluids are used in industry as a sound damper for stereo loudspeakers and as seals in motors

Dr J P Dailey, an ophthalmologist with Erie Retinal Surgery in Erie, Pennsylvania, who had the idea of using the magnetic fluids, said: "If it works, it will be wonderful.

"This could be a major innovation in how retinal detachment repair is done."


I really think it unlikely that this treatment will be useful in humans

Paul Sullivan
Moorfields Eye Hospital
Judy Riffle, professor of chemistry at Virginia Tech, used nanotechnology, the science of manipulating particles smaller than 100 nanometres, or one-hundredth of the width of a human hair strand, to develop the magnetic fluids.

She said the work could allow magnetic fluids to be used in other medical applications, such as targeting chemotherapy drugs - using a magnet outside the body to direct the drugs to hard-to-reach tumour sites, such as those in the lung, prostate and brain.

The team have patented their idea.

Mr Paul Sullivan, a consultant surgeon at Moorfields Eye Hospital, told BBC News Online: "This work is at a very early stage but it is hard to see what advantages it offers over existing treatments."

He warned even if the material was biocompatible, most silicones were prone to a phenomenon called emulsification which limited their usefulness.

'Unlikely to be useful'

He added that only short-term studies had so far been done to test the effect of silicones in the eye, though toxic effects could take years to develop.

Mr Sullivan said the movement of the eye would also break down the liquid bubble into smaller bubbles.

He added: "I really think it unlikely that this treatment will be useful in humans."

Marek Karas, of the Royal National Institute for the Blind, said the research was at an extremely early stage.

But he added: "We are very interested in this research, and always welcome medical advances to add to the treatment of retinal detachment."

The research was presented to a meeting of the American Chemical Society.

See also:

12 Nov 01 | Health
10 Jul 00 | Health
26 Apr 00 | Health
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