July 14, 2010
Hopes Rise For Blindness Recovery
Scientists from The Vision Centre have reported remarkable progress in developing ways to restore sight to people suffering from age-related vision loss.
Non-invasive treatments that enable damaged vision cells to repair themselves are likely to be a common treatment for ageing people within a few years, says Professor Jonathan Stone of The Vision Centre and University of Sydney.
"It used to be thought that in conditions like AMD (age related macular degeneration) and retinitis pigmentosa, you lost your vision cells "“ or photoreceptors "“ and that meant that the resulting loss of vision was permanent. Now we know that, as these conditions develop, there is a pool of damaged vision cells that remain alive in the eye but non-functional and with the correct treatment they can rebuild their outer sections, repair themselves and become active again."
"It's something of a miracle when we used to consider blindness due to AMD and other diseases to be permanent and irreversible. However all our work in recent years now points to it being treatable, and partially reversible."
When vision cells are stressed, the team's research shows, they become damaged "“ and if de-stressed, for example by putting the patient in low-light conditions for a while, they can recover some of their function. "This is not about growing new photoreceptors; that doesn't happen. The recovery of vision comes as damaged photoreceptors repair themselves."
The team is also testing various non-invasive ways to help restore vision in humans, with dramatic results.
In a remarkable clinical trial, Italian colleagues in the Vision Centre, Benedetto Falsini at the Catholic University of Rome, and Silvia Bisti at the University of L'Aquila, dosed 25 patients suffering from "Ëdry' AMD with 20 milligrams of saffron daily for 12 weeks, and recorded vision improvement in nearly all of them.
"It was a rigorous double-blind trial, and the results were tested both using an electroretinogram and by asking the patients to read small text. 23 patients reported and recorded improvements in their vision "“ and could read one or two lines smaller on the eye test card. Several commented that "the fog in my vision has lifted". Also, the team observed the effect slowly reversed if the saffron was withdrawn.
Prof. Stone says his team is now planning a larger clinical trial with saffron in Australia in 2010/11. In collaboration with another overseas member of the Vision Centre, Professor Janis Eells of the University of Wisconsin Milwaukee, Prof. Stone's team has also reported success in treating damaged photoreceptors with near infra-red light, which also promotes their healing. And recently, his work with Professor John Mitrofanis (also at the University of Sydney) has shown that near-infra-red light, delivered to the brain across the tissue of the skull and scalp, can protect nerve cells of the brain from the toxins which can induce Parkinson's disease..
"So we have at least three promising techniques "“ low light, saffron, and red light "“ which are free of side effects, and easy, painless and cheap to use. These approaches should have a relatively rapid pathway to approval for clinical deployment."
In their latest work, the Vision Centre teams at Sydney and at the Australian National University, the latter led by Dr Krisztina Valter, have used microarray techniques to unravel the underlying signalling pathways of eye disease and repair, with a view to improving and fine-tuning the repair pathways for vision cells.
In 2009 they established an electroretinogram laboratory with the aim of measuring with far greater precision the size of the dose of saffron, red light or oxygen needed to assist the eye to repair itself "“ an essential step in the development of therapies for use in human patients.
Prof. Stone says the work on the visual nervous system is also encouraging from another aspect "“ whatever enables eye cells to recover lost function may also apply to the brain and, in particular, to degenerative conditions such as Parkinson's Disease and Alzheimer's Disease.
The Vision Centre is funded by the Australian Research Council as the ARC Centre of Excellence in Vision Science. Further details of progress by Professor's Stone's group and by other scientists working in the centre is available in the Vision Centre annual report for 2008/09.
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