Instant Genius - How science is tackling one of the most common causes of sight loss

Episode Date: February 7, 2025

Dame Judi Dench has recently been in the news speaking about the long-term issue she’s been having with sight loss. The veteran actor has a condition known as age-related macular degeneration that currently affects around 700,000 people in the UK. In this episode, we catch up with Prof Richard Gale, an ophthalmologist based at Hull York Medical School. He tells us the early warning signs to look out for if you are starting to develop the condition, why it’s essential to regularly get your eyesight tested by an optician and why he’s optimistic that the development of cutting-edge treatments can help stop the condition in its tracks. Learn more about your ad choices. Visit podcastchoices.com/adchoices

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but true listening is about more than ease. It's about quality. British audio experts name audio, alongside French acoustic specialist focal, combine handcrafted tradition with, cutting-edge innovation and high-end materials, delivering digital precision with analogue warmth, so you can experience exceptional sound at home. Music just as the artist intended. Visit name audio.com to learn more. Hello and welcome to Instant Genius, a bite-sized masterclass in podcast form. Every Monday and Friday, you'll hear world-leading scientists and experts talking about the most

fascinating ideas in science and technology today. I'm Jason Goodyear, commissioning editor at BBC science focus. Dame Judy Dench has recently been in the news, speaking about the long-term issue she's been having with sight loss. The veteran actor has a condition known as age-related macular degeneration that currently affects around 700,000 people in the UK. In this episode, we catch up with Professor Richard Gale, an ophthalmologist based at Whole York Medical School. He tells us the early warning signs to look out for if you are starting to develop the condition, why it's essential to regularly get your eyesight tested by an optician and why he's optimistic that the development of cutting-edge treatments

can help stop the condition in its tracks. So welcome to the podcast. Thanks very much for joining us. Thank you Jason. It's a pleasure to be here with you. So today we're talking about something called macular degeneration. So I think probably the best way to start is to get out of the way what we're not talking about. So this isn't, like for example,

I've worn glasses since I was eight, nine years old. My prescription has gradually got stronger. But this is something entirely different from that. Yes, that's right. So wearing glasses is almost a normal thing that many of us do now. And that's really due to the shape of our eyes and how the light is bent onto the back surface of the eye. The film of the eye called the retina.

And that's quite different to something called age-related macular degeneration. So let's see, what are the first signs that we know that we're suffering from age-related macular degeneration? Sure, well, Jason, if you don't mind, I might just take a step back and perhaps talk a little bit in broad terms about macular degeneration. So this is a condition that affects the very back surface of the eye. If you imagine our eyes a little bit like a camera and the back film is called the retina, it's the very centre part of that. size of a pin hard or perhaps even smaller, that's the macular, and that's the area that gives us our best quality vision. And this condition called degeneration occurs in older people, typically over the age of 50. Now, to answer your questions of how this affects the viewing of

people with the condition, it can affect in different ways, and it can affect in different ways because there are different types of this degeneration. The very earliest stages called dry, in some people may hardly be noticeable or noticeable at all, but the very early symptoms may be requiring more light, struggling to see the very smallest print, or perhaps, say, drop off in the quality of the vision. So how do we get a diagnosis for this then?

Yes, it's a great question. The diagnosis usually comes through a regular and routine optometry appointment. So all of the high street optometrists that we attend, you for your glasses, me for my glasses, for example, and our optometrists are attuned to looking at the back of the eye routinely and noticing the change. And that may well be prompted by these symptoms of perhaps difficulty looking at the fine vision reading, for example.

Very unusually, individuals may notice a sudden problem to their vision and they haven't attended the optician for a long time. And then those individuals are either referred via their general practitioner or perhaps even straight to eye emergency departments. So having said that, what's the general advice? How often should we be going to the optician? Yes, great question there, Jason. So there are standards which are set for you and I and everybody in terms of how often we should all be attending optometry appointments. And they are every two years, by matter of course, even if we don't have any symptoms.

And that's for a general eye health checkup, not just for our glasses, but also for the health of the eye. Now, for some individuals where there is a condition, there may be a recommendation that that is more frequently, perhaps every year or unusually more commonly than that. So how common is this condition then? What do we know about that? Well, age-related macular degeneration affects around 700,000 individuals within the UK. So actually, it's a little bit more common than many people think. The prevalence, or how common it is, is increasing over time.

And that may well be a factor that eye health care professionals are getting better at diagnosing the earliest stages, but it's also a reflection on our ageing population and perhaps our contributory factors for the development, such as diet and smoking. So what's it like to actually experience and sort of how does it progress? Yeah, great question. So this early stage of the age-related macular degeneration can progress to more severe forms. And really there are two forms. There's something we call wet. which is a description of leaking or bleeding in the very centre part, the macula.

And that is quite different for something called advanced dry or atrophy is the other term for that. So if we talk about those two separate conditions or linked, but quite separate in a way they manifest in a different way. So the wet macular degeneration typically affects one eye first. it typically affects with a sudden drop-off in the vision and perhaps even distortion of straight lines. So if you can imagine that blood vessels are elevating this macular, this perfectly formed flat structure and it's elevating it,

almost to form an undulation. And then the light rays are trying to refract onto, trying to shine onto this undulation. And of course they're projecting in a distorted manner. So individuals experience distortion of straight lines. And that typically occurs in one eye. And then there is a chance of it occurring the other eye, which is about 10% per year.

Now this wet degeneration is quite different from dry degeneration, the advanced forms of dry degeneration called atrophy. And that is a condition where there is typically loss of the light-senseless. cells, the so-called photoreceptor, and they're supporting cells underneath. So they form a gap in these light-sensitive cells, and that forms a gap in the vision, and that may manifest, that may present individuals by a gap in the vision. So perhaps if you were looking at something, you know, looking at the window now, or looking at a photo, it may be the nose on the individual in that photo is missing, or

there is a blank patch that one can't see as well. So how is that different from, I think they call them floaters, which some people have? Oh, this is quite different. So let's go back to that analogy of the camera that we talked about and the retina being the back film and the mac of the centre part affected the maconeration. Let's extend our analogy of the eye now with the front portion

having a lens at the front and a front window. And in between that lens at the front and the back of the eye, the film and the camera is a large volume. And that volume is occupied by a natural jelly. As a part of the normal aging process and perhaps more commonly in short-sighted people, that jelly begins to separate away from the retina. It begins to move forward and degenerate. And as it degenerates, it clumps into small particles. And those particles cast shadows on the retina on the back surface of the eye, and they're seen as floating objects.

So really, it's a very different process which is occurring. Now, it's quite a common aging process, floaters. However, unusually, there can be other conditions, other disease processes, which cause floaters. objects. So you mentioned there smoking as being, obviously, everybody knows how unhealthy smoking is, but are there any other sort of risk factors, you know, sort of, I'm thinking maybe gender or other lifestyle factors? Yes, there are many lifestyle factors and indeed what we may call modifiable factors as well as non-modifiable factors. Let me explain those terms. So the non-modifiable factors predominantly will be our genes, what we're made with our genetic code. And we know through

experience that if one has macular degeneration, about a quarter or a third of our future generations may experience that through the genetic coding. Now, the genes responsible are numerous, but perhaps there are around about 20 of these genes which explain about half of that hereditary pattern. Now, the modifiable factors which perhaps were equally interested are are numerous as well. And some of these seem quite obvious. Spigarette smoking, tobacco smoking is probably the most common one. And that causes the macular degeneration to develop sooner and more severely. And of course, none of us should smoke, and that's a public health message.

But also, there are other factors as well, our diet. So typical diets, which are perhaps high in saturated fatty acids, mean that we're more likely to develop macular degeneration. And also strong sunlight, the UV light, which comes from strong sunlight, also predisposes to developing macular degeneration. So these are some of the typical forms. So of course, like all of us, we should all be having a balanced, healthy diet with our five a day. None of us should smoke, and we should all be wearing our sunglasses and our shades out on sunny days when we get them. You thought this was your run club era. Turns out it was more of a thinking about run club era.

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So what's the idea behind that? Sure. So Jason, we talked about this wet macular degeneration where there's leaking at the back of the eyes. And that occurs because of abnormal blood vessels which really migrate through this retina at the back and will begin to lift it up. And those blood vessels are abnormal. They shouldn't be there. They leak and they bleed. So the concept of treating individuals with wet macular degeneration, remember, that's not everybody, is that a chemical is injected into the eye, which tells these blood vessels to stop growing, to stop leaking and to regress to shrink down. And that's in the form of an injection medicine into the eye. And it's given on a regular basis, every month to start off with and then in the majority of people, less often there afterwards.

And this has really been a fascinating step forward in eye health care. It was available to us around about 15 or 20 years ago, but it's actually half the amount of blindness. due to this condition. And that's remarkable, absolutely remarkable, with age-related macular degeneration being the commonest cause of blindness within the UK. So how about other options then? I've heard light therapy can perhaps be used. Yes, so we'll now talk about the dry degeneration, and really there's those two aspects of the dry that perhaps we were beginning to talk about, that atrophy, which was the gaps within the vision. Now, very recently, trials have been successful in showing that injections of a medicine, which also blocks another chemical, slows down the size of the growth of that gap,

the size of the atrophy. And it slows it down by about a fifth. Now, the regulators, the health regulators in the United States, have approved this. But the regulators within the European in space have not approved this because they feel that the benefit to the risk ratio did not warrant issuing a license as a medication that can be used and can be approved. So that's really about this gap form. Now, before this atchofil gap form occurs, are the earlier stages of macular degeneration, those which cause less symptoms, less difficulty in reading than the more advanced forms. And there's been a lot of interest recently of how to minimize the early forms and perhaps prevented turning into the late forms. And that's where red light therapy comes into play. And it's

fascinating. Shining red light of a very specific wavelength, done by healthcare professionals, not by our cells, but done in a very specific way, can change the metabolism of specific components within those light-sensitive cells, such that it tries to reduce the waste products produced by the metabolism, which is the underlying cause of this macular degeneration. So there have been trials to look at the success of that, and I must say it's a little bit controversial amongst ophthalmologists at the moment. Many feel that there may well be a signal to a benefit in it helping, and others are just a little bit skeptical until they have more information,

larger scale studies and trials, to understand what the true benefit of this is. So obviously this, anyone's suffering from this, their daily life can be severely affected. And I know some people can register as being sight impaired. So at what point are we eligible for that? You know, how do we do it and what does it mean? Yes, it's really important for individuals with impaired vision or reduced vision. And let's just remind ourselves there are about 2 million individuals within the UK who do have a form of sight impairments,

it's really important for individuals with sight impairment to maximize their vision and also to obtain support. And one of those mechanisms is to be registered as so-called sight-impaired or severely sight-inpaired. Those terms used to be synonymous as partially sighted or blind, but we don't really use those terms anymore. And to qualify for being registered as sight-impaired, the vision in both eyes must be quite reduced, off and down to about the ability to read the top letter on the opticians chart in both eyes. Now, there are some exceptions if predominantly the central vision or predominantly the peripheral vision is used. But that's the level of vision.

And really, a healthcare professional has to advise to that and then effectively go through the process, form filling, etc. And that then is a communication through to the individual's general practitioner, to social services, to the Office of Census and Population Survey. And what it does is it enables support to be put in to the affected individual as they require it. So going back to treatments then, we mentioned a few options there with either drug-based or this light therapy, concept. Are there any sort of future ideas that look promising in the pipeline? Oh, wow, yes. The future's just amazing with the potential therapies which are coming along. In fact, these are being trialled at the moment and I remain optimistic that we'll perhaps

have a menu of therapies. Let's just walk through a few of those. Now, let's imagine that this chemical which we inject in the eye is able to be produced by our own cells on our own body. is our own natural reservoir of it. Well, actually, that is being worked on at the moment by genetic therapy, gene-based therapy. So let's imagine we take what's called a viral vector, like a virus, and the genetics of that virus is changed to insert the coding to produce these medications which stop the leaking. Now that viral vector, so it's called as injected into the eye or put into the eye. It inserts into our natural, so-called host genetic code. And then our own machinery begins to produce that chemical. So it's a really neat idea. And this is beginning to be trialled.

And initial results are really quite successful in being able to maintain the level of vision, but also reduce the number of these injections, which are required. So really quite smart idea. Another concept which has been used are implants into the eyes. So not just injections, an implant which will last longer, which will effectively degrade within this jelly we were talking about over many, many months and perhaps even years, and slowly release the medication. And then a third concept is,

imagine we had a little port or a reservoir, which was inserted into the site of the eye, the white of the eye. And instead of an injection into the eye of the medication, the port of the reservoir was filled up intermittently. And then the medication slowly leaked out into the eye over a period of many months. So each of these strategies have been tried to address these key unmet needs of reducing the amount of injections in the long term. So it sounds like there's a lot going on then. So you're optimistic that we can beat this? Oh yes. So. am. So if we look at the real successes of treating this wet macular generation to start off with,

it's reduced vision lost by about half 50%. That leaves 50% more work to do to try and restore vision fully. Now, perhaps we'll never be able to get to 100%, but we'll hopefully shift the needle towards 8 or 90%. And that can be done through new therapies. It can also also be done through a real passion of mind, which is detecting people early. And let me just explain about that for a moment. So we know through experience that when this wet macular degeneration comes along, the effect on the vision gradually occurs, or actually quite rapidly occurs over many weeks and months, such that there's a decline in the vision from relatively normal vision,

down to about seeing the top letter on the opticians chart over about two years. And that decline is relatively predictable. And sometimes we see people presenting with poor vision. And when we see people presenting with poor vision, we can't actually restore much vision or sometimes not at all. But when we see people presenting with a relatively early disease, early development of this, we can try and retain vision at that.

earlier level when the vision isn't quite so poor. So a real passion of many of us in particular me is to be able to catch people really early, so-called early detection of the treatable forms. And I'm really keen that we understand how we're able to do that, not just locally, but nationally and perhaps internationally. So the kind of takeaway piece of advice then is keep up with your regular opticians appointments? Absolutely. Keep up with your regular optician appointments. If you notice a sudden change in a vision, get help, seek help, go to your optician or phone up your optician or perhaps even your general practitioner. Seek help, don't ignore it. And so that we can catch this disease. And probably the third piece of advice would be all those good things which we all try and do by maintaining the health of our eyes, which is the same message about maintaining the health of the rest of our body. A good diet. exercise, keeping well, and to refrain from cigarette smoking, tobacco smoking if possible. Thank you for listening to this episode of Instant Genius, brought to you from the team behind BBC

Science Focus. That was Professor Richard Gale. If you liked what you just heard, then please do consider subscribing to Instant Genius on your preferred podcast platform. The current issue of BBC Science Focus magazine is out now. Pick up a copy wherever you buy your favourite magazines, or download us on your app store of choice. You can also find us on Apple News or online at sciencefocus.com. This podcast is sponsored by Name, Audio and Focal. The texture and emotional depth of music can be lost through digital sources or poor signal. Name Audio believes you can have digital precision with analog warmth.

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