DESLEY BLANCH : Australian researchers hope that it may soon be possible to restore vision to people with failing eyes by removing their old lenses and injecting new plastic ones to restore their original sight.
The new polymer developed through the Vision Cooperative Research Centre has the properties of a young person's lens and may one day be used to improve the sight of people with age-related long-sightedness. The research was presented at a recent biomaterials conference in Sydney.
Professor Arthur Ho leads the project at the Vision Cooperative Research Centre in that city.
PROFESSOR ARTHUR HO : We got a lot of interest Desley, but what is more particularly encouraging to us was it wasn't just about the technology or the chemistry. People were interested because they saw that it was personally beneficial to them.
DESLEY BLANCH : Well age-related long sightedness is referred to as presbyopia and as we're all living longer, what proportion of the population is affected and likely to be affected in the future?
PROFESSOR ARTHUR HO : Well, in the developed world it's about 35 per cent of people that is over the age of 45 to 50 and would probably need reading glasses. The projection that for example in Australia, in the next 10 years, that figure will exceed 40 per cent.
But more importantly, to look at it in another way, for example, my daughter is four years old. According to the World Health Organisation statistics, she's got better than 50-50 chance of living past 100. Now, that means that she is going to need her reading glasses for longer than half her life.
DESLEY BLANCH : So what happens to our eyes as we age, what's going on?
PROFESSOR ARTHUR HO : Well, it actually happens from the time we're born. We know that little children can see right up to where their nose is. As we get older and older, we have to focus further and further away. Around about the age of 45 to 50, we find that our arms are no longer long enough and that's when we start needing reading glasses.
DESLEY BLANCH : So what's occurring in the eye to prevent us from having this close-up focus that we once had?
PROFESSOR ARTHUR HO : Well, there is a tiny little lens inside your eye called a crystalline lens, it's about the size of a pea. But that little lens is responsible for all the focusing that your eye can do. Now just like the rest of our body, as we get older that lens gets harder and harder. When we're young the lens is soft and it can change shape, because it can change shape, it changes power, so we can see up close and as we get older it gets harder and we can no longer change focus.
DESLEY BLANCH : Your research team has developed this polymer with certain properties that can be injected into the lens capsule. So tell us about those properties and what happens after its injected?
PROFESSOR ARTHUR HO : Well, what we wanted to do was to make the lens the same softness as a young person's lens again. So the material that we develop, I try to mimic or resemble exactly the same property as a young person's lens. What that means is we have to make it optically transparent to light just like a normal lens. We have to make it have the same density but more importantly, it has to be very soft so it can change shape just like a young person's lens.
DESLEY BLANCH : And what's this polymer made from?
PROFESSOR ARTHUR HO : The chemist will classify that as a siloxane-based polymer gel. One of the things we have to do is make sure the material is not just of the right properties that I mentioned, but it is also safe in the eye, so it has to be biocompatible.
DESLEY BLANCH : And it is biocompatible so how do you keep this polymer in the eye?
PROFESSOR ARTHUR HO : Well, it turns out that keeping it in the eye is probably the easier part of the whole deal. To make it stay in the eye, we just have to make it clump together, so the difficulty is being able to inject something into the eye that is clumpy. So what we've done is design a material that is like a liquid at the beginning, so it is like fairly runny maple syrup or honey if you like.
After we inject it into the eye, we can shine the light on it briefly. This light - what it does is it cures the polymer; by curing it, it changes the material into something that's a gel. In other words, it's a little bit like Aeroplane Jelly or Jello and that makes it stay in the eye.
DESLEY BLANCH : So where did the idea originate to use a non-biodegradable siloxane based fluid for this particular application?
PROFESSOR ARTHUR HO : Well, it's a bit like Leonardo's helicopter I guess. The concept goes back quite a long way, back to 1960s in fact, when someone suggested that why not make the hard lens as soft as a soft lens. And we were lucky to work with Professor Parel at the University of Miami. He's one of the early innovators of this approach and he perfected the surgery. That was in the 1980s. But the problem is that back in those days, all they had available was silicon oil, which didn't have any of the right property.
So for the last 20 years, the quest really is for the right material and our polymer team has been working on that and ultimately come across this siloxane-based material which has all the properties that we need.
DESLEY BLANCH : Well, you had a breakthrough and that was some time ago. How long has it been that you've been developing this particular polymer?
PROFESSOR ARTHUR HO : The project really started in the early 90s when the CRC for Eye Research and Technology was formed and the Vision CRC or the Vision Cooperative Research Centre took the ball and ran with it, so to speak. All the way along, we've been working on mainly the polymer development, that's the key to this whole technology.
DESLEY BLANCH : Well the lens has been tested on monkeys in China. So, what results?
PROFESSOR ARTHUR HO : Well, we're very excited about the results. We're able to demonstrate two things. One is that it really works in a real life eye. And the second thing is the monkeys were actually able to focus from long distance down to very, very close, about 10 centimetres away. But more importantly, unlike a pair of reading glasses, they can focus on every distance in between as well. Now, that is the equivalent of rejuvenating the eye to about a 20 year-old.
We found that when we started doing the experiment, we were doing a lot of the measurements on machines that we developed to test the technology out. We have these robots that we developed that can resemble exactly what the eye does in the eye. So ultimately what we had to do though is to make sure that it works in the human and the closest model if you like, the closest relative to what happens inside a human eye is the monkey's eye and that's why we tested it on that.
DESLEY BLANCH : How did you come to be working with monkeys in China?
PROFESSOR ARTHUR HO : Well, this is where one of the strengths of the Australian Government's Cooperative Research Centre is. With the Vision CRC had an opportunity to work with a lot of very good organisations around the world. For example, we worked with Bascom Palmer (Eye Institute) in the University of Miami, and in this instance, we have a working collaboration with a university in Guangxhou and the eye hospital there. So we're able to make use of their facility.
DESLEY BLANCH : So where else has the fluid lens been tested and how?
PROFESSOR ARTHUR HO : Well, the Vision CRC are collaborating with a large number of participants, in particular, we have four groups working on this project. We have the Bascom Palmer Eye Institute which I mentioned already at the University of Miami. They're probably the best eye research hospital in the USA.
We're working with the LV Prasad Eye Institute in Hyderabad in India, another world renowned eye hospital. But also the polymer development and research work is being done by the CSIRO Division of Molecular and Health Technologies in Melbourne. All of that research is being headed up of course by the Institute for Eye Research here in Sydney.
DESLEY BLANCH : Is the surgery for injecting the polymer complicated and/or risky?
PROFESSOR ARTHUR HO : That's a good question. The bottom line to that is we are trying to develop a surgical technique that doesn't depart much from standard technology. So you might be familiar Desley with a condition called cataract where the eye starts to go cloudy and so the eye doctor has to go in and remove the lens of the patient and replace the lens with a hard lens. The lens is called an intraocular lens. Now this surgery, a cataract operation happens 160,000 times a year in Australia, so it's pretty much bread and butter, very common surgery for the eye doctor.
The surgery that we use to put the polymer into the eye changes only very little from that surgical procedure. The main difference is instead of putting in the hard intraocular lens, we put in a soft polymer gel that can change shape, so the patient can see up close again.
DESLEY BLANCH : When would you hope to move to human trials?
PROFESSOR ARTHUR HO : Well, the plan is to be able to start human clinical trials in one or two years time. Right now what we're doing is doing all the long term testing to make sure that it is safe in the human eye.
DESLEY BLANCH : What issues or conditions will you be monitoring and checking for?
PROFESSOR ARTHUR HO : That's a very good question. In fact it forms the bulk of our work at the moment. First and foremost, we have to make sure the material is safe in the eye. That means we have to test, for example, leakage of the material out from the lens. We have to make sure that even if it does leak out it doesn't cause any harm to the eye or to the rest of the body. But as I mentioned the material is known to be very biocompatible.
We have also done short term studies already to show that it is safe in the eye. And finally I should mention that we have developed additional technology, for example, we have a valve that we can put in the lens to stop the polymer from leaking back out of the lens. The second thing we have to do is to make sure that it keeps working, which means it stays soft for the long term and it stays clear for the long term.
DESLEY BLANCH : So I guess at this stage with the technology you might be looking for some prospective commercial partners. Are there any showing interest?
PROFESSOR ARTHUR HO : Well, that's actually one of the goals that was set us by the Australian Government in funding the Vision Cooperative Research Centre to create technology that is beneficial to Australia and to the rest of the world. So right now the Vision Cooperative Research Centre is working on product development on this technology, with a company called Adventus Technology.
Adventus Technology is a company that is especially set up to take these type of technologies to market, not just in Australia, but in Europe, in USA, and ultimately worldwide
DESLEY BLANCH : Professor Arthur Ho from the Vision Cooperative Research Centre in Sydney where they are creating fluid lens technology to restore youthful vision to older eyes.
Professor Arthur Ho
Director of Presbyopia Program
Vision Cooperative Research Centre
Professor, Visiting Fellow, School of Optometry & Vision Science
The University of NSW, Sydney, NSW 2052