Search for tag: "retina"

Interviewer: Age-related macular degeneration is a leading cause of vision loss in adults in the United States. The effects on the central vision caused by this disease can significantly impact your life, including the ability to do daily activities, the things you enjoy, and it could also lead to a loss of your independence. However, the good news is, if caught early, the progress of the disease can be slowed.

Dr. Monika Fleckenstein is a professor of ophthalmology and vision sciences at the Moran Eye Center. She's a retina specialist with an emphasis on this condition. Dr. Fleckenstein, let's start with what is age-related macular degeneration. What's going on?

Dr. Fleckenstein: Yeah. So age-related macular degeneration, and we usually say AMD, this is a disease in the back of your eye, and it causes that your central vision may get worse over time. As the name says, the most important risk factor is your age, where you cannot do a lot about it. But we also know other risk factors, which is, for example, smoking or unhealthy lifestyle. And we also know that there's a strong genetic component in this disease.

Interviewer: You called a . . . it impacts your central vision. Is that what you said? Explain what that means.

Dr. Fleckenstein: Yes. So if you look at a paper and try to read, you do this with your very central vision. So this is the area of sharpest vision. This is an area in your eye which we call the macula. And the very center of this macula is the fovea. This is actually the area of sharpest vision, and this is the area you need for reading, for recognizing faces. So this is the highest resolution in your eye.
How Age-related Macular Degeneration Impacts Daily Functioning

Interviewer: I want to know how age-related macular degeneration impacts people's vision in their daily functioning. Talk to me about that, from what you've seen with your patients.

Dr. Fleckenstein: We have different stages of age-related macular degeneration, early stages where you may not experience any symptoms, and then we have the later stages of the disease that you may develop a grayish area in your central vision. In certain subtypes of the disease, you may even develop a central dark area where you're not able anymore to recognize faces or read.

The symptoms patients experience is dependent on their disease stage, but usually, when I see patients with earlier stages, I actually ask them, "Do you have difficulties in dim light?" And so when you go to a restaurant and if you try to read the menu and the light is dimmed and maybe candlelight, this is actually where the patients realize first symptoms. Then also, when they come from bright light outside entering a room, and they may realize it takes them longer to adjust to these changing light conditions as before in their life or compared to the people they are surrounded by. So these are typically the first symptoms of the disease.

And so in later stages, when there is the real damage of the cell layers, the photoreceptors, patients may experience that they have difficulties to read. In very late stages, patients may even not be able anymore to recognize faces. And this is probably, you know, the end stage of the disease where they are not able anymore to read or recognize faces.
Early Detection of Age-related Macular Degeneration

Interviewer: And the importance of early detection in age-related macular degeneration, it's pretty critical, from what I understand. Can you expand on that?

Dr. Fleckenstein: Most sad situations are those where patients have the wet stage and did not receive treatment, and then you face a stage where treatment is not possible anymore or is not really effective anymore if patients have developed scar tissue. And this is why it's so important that if you realize symptoms, never hesitate to reach out to your doctor and ask to have a look.

And when I'm seeing actually my patients with earlier stages of the disease, I explain to them the symptoms of the later stages and tell them, "Please never hesitate to contact me and my team if you experience these changes." And I even tell them it's, you know, "Even if you do not have these specific changes, but if you have a weird gut feeling, please reach out," because sometimes, you know, patients just experience something is off, something is weird here. I cannot really say what it is. Never hesitate. Try to be seen by an ophthalmologist just to make sure that nothing is going on.

Interviewer: And if it's caught early, there are some things you can actually do about it. Tell me about that.

Dr. Fleckenstein: In the earlier stages of the disease, there are certain constellations or certain findings in the back of your eye where we would recommend that you take certain nutrition supplements. So it has been shown in a large clinical trial, the AREDS study, that a certain combination of supplements may delay the progression to late stages, but just if you have a certain constellation of the disease. So the study has also shown that just taking these supplements without having any sign of AMD will probably not have a positive effect. But if you have certain signs, it has been shown that the disease may be slowed down.

In general, we would always recommend, but this is more or less a general recommendation to the whole population, to have a healthy lifestyle, not to smoke. And actually Mediterranean diet has been shown, not only in age-related macular degeneration but also in cardiovascular diseases, that this can be beneficial to prevent the development of macular degeneration and also of the late stages. And Mediterranean diet, this means vegetables, fruits, olive oil, fish. So more a combination of nutrition into this direction.
When to Get Checked for Age-related Macular Degeneration

Interviewer: So since catching it early is so crucial, how often should somebody actually get their eyes checked for macular degeneration?

Dr. Fleckenstein: Yeah. So this really depends on age. So the American Society of Ophthalmology, they actually recommend to have an eye check when you become 40. Then it highly depends if your ophthalmologist finds anything, if you have any signs of a disease in the back of your eye. With ages of 65, we would recommend yearly eye exams. But of course, if you have a positive family history for age-related macular degeneration or if you have certain risk factors, I would recommend to be seen by an ophthalmologist more often and even in earlier ages.
Diagnosing Age-related Macular Degeneration

Interviewer: And in the diagnosis part, are you able to diagnose the disease? How far in advance before a person starts experiencing symptoms are you able to diagnose the disease with the equipment you have?

Dr. Fleckenstein: So we can see on a micron level changes in the back of the eye. Within the last decades, we have seen such a rapid improvement on resolution. And again, we can see tiniest changes in eyes. We indeed also see patients without any symptoms who are not aware of having any problems, and we may pick up earlier signs of the disease, and we can certainly see if macular degeneration is present or not.

Interviewer: That peace of mind is probably great for a lot of patients when you tell them, no, that's not it, that's something else.

Dr. Fleckenstein: Yes. But, you know, I tell my patients as well, as the time has changed so much and we have these dynamics right now, having the diagnosis of AMD today is something completely different than 20 years ago.

Interviewer: And why is that?

Dr. Fleckenstein: Because first of all, I believe within the next 10 years, you know, we will have more treatments available, and for the wet late stage where everyone is so scared about, we have wonderful treatment available, and this treatment really works well. And I always say I have respect for the wet late stage, but I'm not scared of it anymore because if this is treated well, patients can keep their vision for many, many years.

Announcer: Examining the latest research and telling you about the latest breakthroughs. The Science and Research Show is on The Scope.

Interviewer: I'm talking with Dr. Bryan Jones, an investigator at the Moran Eye Center at the University of Utah. Now anyone who sees you knows that you carry a camera around with you wherever you go.

Dr. Jones: I do.

Interviewer: And I suspect your love for photography might have come before you delved into science.

Dr. Jones: It did, yeah.

Interviewer: I'm wondering if that passion for photography and how maybe we see the world or how the camera sees the world sort of influenced what type of research you're doing now?

Dr. Jones: I came to photography initially in college. My first major was film studies. And I spent a lot of time with a Leica M6 camera and a Canon 1D camera that my parents had. And I fell in love with photography. I've had the privilege of knowing a couple of friends who have retinitis pigmentosa. One of my friends is an army veteran, and I've watched him go blind. So for me, the ability to do photography and to share what I see is a constant reminder of why the work we do is so important.

Interviewer: And what are you looking at these days? What's driving your research?

Dr. Jones: So our lab has two main focus areas. The first is understanding how the retina is wired. So the retina is this piece of gauzy tissue at the back of your eye that is an extension of the brain. And this brain tissue at the back of the eye is sort of a layer cake-like structure with 7,200 neurons or more in our human eyes. And it captures light, photons of light and then computes all the parameters required for vision. Captures contrast and luminance and edges and movement. And calculates all these parameters and sends that information on to others and brain and cortex and sub-cortex for higher processing.

People have been studying the retina for about 150 years, and we still don't know precisely how all those 7,200 or more neurons are wired. And that's the first mission of our lab is to try and pull apart that wiring and identify all the neurons and figure out how they are precisely wired together. That's a field called connectomics.

The second main mission of our lab is to understand how that structure and how the neuron identity and how the wiring is altered in diseases like retinitis pigmentosa and age-related macular degeneration that steal vision from us.

Interviewer: So you're looking at circuitry itself?

Dr. Jones: Yes, ma'am.

Interviewer: And how are you doing that?

Dr. Jones: So there are two new approaches that have been pioneered. The first one that was pioneered by Dr. Robert Mark here at the University of Utah called computation molecular phenotyping. We basically use antibodies to serially label tissues and pull out smaller molecule fingerprints that uniquely identify populations of neurons. And then we insert those data into electron microscopy datasets.

So we basically take the retina and section it very thin. Each section is thinner than the wavelength of light. There are about 90 nanometers. And then we section in the case of the mouse retina that we recently finished, about 1,490 nanometer sections, and then we reconstructed those 1,400 sections into a digital layer cake and create a volume and then we go in by hand and trace neurons all the way through the dataset along with all their connections, their synapses and their gap junctions.

Interviewer: So the hope is to create like a three dimensional representation?

Dr. Jones: Yeah. A three dimensional representation that we then extract out circuit topologies. So it turns out the circuit topologies are far more complex than we thought they were. And so we're now having to develop new software that can allow us to visualize how complex some of these topologies are. The circuit topologies are things that give us excitation and inhibition and ultimately end up tuning response profiles in retina.

Interviewer: You know, if you think about circuitry in how most of us think about circuitry, I mean, if you look at the circuitry like in a computer or in the electronic system of a car, I mean, it doesn't exactly tell you how it works. Or does it?

Dr. Jones: So there was a pretty famous paper that came out a few months ago where they took a standard computer integrated circuit chip and they took it apart digitally and they tried to predict how it would work. And it turns out they didn't have a whole lot of information. It didn't function the way it should have functioned. Or at least their models, their predictive models that they thought how it would behave, it didn't actually behave the way the chip actually did.

So while the circuitry is what we're after and the circuitry in any neural system is sort of the substrate that gives us a basic performance profile and ultimately makes us who we are, there is still a lot we don't know. And so for us the connectomics framework, the circuitry framework we're trying to obtain is only the basic starting point.

It is a framework and on that framework we have to hang physiology, we have to hang physics and we have to put molecular biology and we have to put genetics into it. And so for us it's only the very beginning of understanding how neural systems are wired. Even though the science community has been studying the retina for 150 years. In a lot of ways, we are still right at the very beginning.

Interviewer: So it's kind of new frontier. Something that hasn't really been done this way before.

Dr. Jones: Yeah, exactly.

Announcer: Interesting, informative and all in the name of better health. This is The Scope Health Sciences Radio.