07:03pm Tuesday 22 August 2017

Blindness recovery in sight

Photo by Eveinella / http://www.flickr.com/people/naturemusicfreak/
Photo by Eveinella / http://www.flickr.com/people/naturemusicfreak/

Dr Krisztina Valter and doctoral researcher Rizalyn Albarracin of The Vision Centre and The Australian National University have successfully demonstrated recovery of vision cells in the retina following near infra-red treatment applied after damage was sustained.

Their advance has raised hopes for the development of a practical, low-cost and painless treatment for damaged eyes – including for patients suffering from dry macular degeneration (dry AMD), now the most common cause of blindness in developed countries.

The finding, made using an animal model, builds on the evidence the team has established showing that pre-treatment of eyes with near infra-red can help to minimise damage caused by bright light and enhance recovery.

“Macular degeneration is responsible for around a half of the cases of blindness in Australia. The dry form, for which there is still no cure, accounts for 80-90 per cent of cases,” said Dr Valter. “Our research shows clear evidence of recovery of vision cells from light damage, a good model for what happens in dry AMD.”

“Given the very high costs of blindness to any economy, it is encouraging to know that there is a simple, affordable technology in prospect which could help to reduce it.”

Ms Albarracin said that treating the retina with just a few minutes exposure to soft near-infra-red light a day for less than a week had produced a remarkable recovery in damaged photoreceptors (vision cells) which ordinarily would have died.

“You only have one set of vision cells, so if you lose them they can never be replaced. When they are damaged or stressed, they shut down and gradually die or kill themselves. You get a horrible ‘hot spot’ of dying cells in your retina, which gradually spreads out in a sort of domino effect until your vision is gone,” she said.

“We have found that treating the cells before, during or even after light damage raises their protective factors and resistance to stress, and slowly allows their vision function to return. The retina looks really sick – but then it just bounces back. It’s almost a kind of a resurrection.”

Since only a few people know in advance they may suffer vision damage from bright light and can be pre-treated, knowing that near infra-red treatment soon after injury also causes the cells to heal well is an important step towards developing a practical therapy for people who are losing their sight either from injury or slow-onset conditions.

The technique could potentially be used to treat a wide range of forms of vision loss, including dry AMD, retinitis pigmentosa, inflammation of the retina and some diseases of the optic nerve.

“We’re using an array of small LEDs (light emitting diodes) that have been tuned to produce near infra-red light at a particular wavelength.  These are fairly cheap, making a potential treatment very affordable – especially when you consider the overall costs of blindness,” said Dr Valter.

She added that the evidence yielded by the latest research is now so persuasive that the team could move to human trials this year, if they can secure a clinical partner.

“Near infra-red therapy is very benign and involves no discomfort to the patient. It is already approved by the US Food and Drug Administration for use in sports medicine, for hair loss and so on – so developing a novel therapeutic application for the eyes is likely to be less complex and protracted than, say, developing a new drug.”

Their paper ‘Photobiomodulation protects the retina from light-induced photoreceptor degeration’, co-authored with Janis Eells, appears in the latest issue of the journal Investigative Ophthalmology and Vision Science.

The Vision Centre is funded by the Australian Research Council as the ARC Centre of Excellence in Vision Science.

More information:
Dr Krisztina Valter, The Vision Centre and ANU – 02 6125 1095 or 0411 423 119

Rizalyn Albarracin, The Vision Centre and ANU – 02 6125 6493 or 0424 722 449

Professor Ted Maddess, The Vision Centre – 02 6125 4099 or 0411 443 415

Julian Cribb, The Vision Centre media contact – 0418 639 245

Martyn Pearce, ANU Media – 02 6125 5575 or 0416 249 245

http://www.vision.edu.au/


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