The falls researcher behind the Physiological Profile Assessment on the two vision tests most eye exams skip, why walking speed is oversold as a screening tool, and what a wristband can learn from a week of ordinary walking.
Key Takeaways
- Standard eye exams measure how sharply you see. Two other parts of vision, contrast sensitivity, and depth perception, predict falls better, and both are routinely left out of a normal appointment.
- Vision does more than spot obstacles. It feeds balance directly. Close your eyes and your body sways roughly 30 percent more, which is why most people cannot hold a one-legged stance with their eyes shut.
- Seniors who wear multifocal glasses and get out of the house often may fall less with a second, single-lens pair kept for walking outdoors. Multifocals stay useful indoors and behind the wheel.
- A walking-speed screen set at 1.0 meters per second flags more future fallers than the 0.8 threshold in the World Falls Guidelines. Speed alone is still a weak test on its own.
- A wrist sensor worn for a week can capture walking speed, step count, longest walk and gait smoothness. Those measures predict fall-related hospital admission, frailty, and several chronic conditions.
Medical Disclaimer: This interview is for general education and is not medical advice. Nothing here replaces an assessment by a qualified clinician. Talk to your own doctor, optometrist or physical therapist before changing your glasses, your exercise routine, or how you manage a health condition.
Stephen Lord, PhD, DSc, is a Scientia Professor at the University of New South Wales and a Senior Principal Research Fellow at Neuroscience Research Australia (NeuRA), where he directs the Falls, Balance and Injury Research Centre, established in 2014. He has published more than 600 papers on instability, falls and fractures in older people and in clinical groups with balance impairment. His work follows two themes: identifying the neuropsychological, sensorimotor and balance risk factors for falls, and developing and testing ways to prevent them. Current projects include digital gait biomarkers, reactive step training and cognitive-motor interventions, along with studies of fall risk in people with stroke, multiple sclerosis, Parkinson’s disease, chemotherapy-induced peripheral neuropathy and cognitive impairment. He contributed to the World Falls Guidelines, and in December 2019 he received the Lifetime Achievement Award from the President of the British Geriatrics Society for his contribution to falls research. He developed the Physiological Profile Assessment, distributed through NeuRA as FallScreen and supplied to more than 150 research and clinical settings around the world. He spoke over video from Sydney, Australia about what a real falls assessment measures, why two of the three parts of vision that matter go untested, and what a wrist sensor can learn from a week of ordinary walking.
This conversation has been edited for length and clarity.
On this page:
On What a Standard Eye Test Measures
On Why Contrast Fades With Age
On Depth Perception and the Two-Rod Test
On the Two Ways Poor Vision Leads to a Fall
On Multifocal Glasses and the Case for a Second Pair
On Walking Speed as a Screening Test
On Measuring Gait From the Wrist
On What a Week of Ordinary Walking Reveals
On the Physiological Profile Assessment
On Training Balance With a Dance Mat
On the One Thing to Ask an Optometrist
References
On What a Standard Eye Test Measures
Thank you again for making the time, and for the quote you sent for an article on fall risk. One line in it stuck with me. You said it is not only about seeing clearly, it is about being able to judge contrast. Can you expand on that?
The standard test for vision is called visual acuity, and that is really the ability to see fine detail. Now that is crucial in everyday life, like reading the paper, seeing things clearly in the distance. But we use vision a lot more than just for fine detail. One of the things we do is judge contrast. A classic example is the ability to discriminate between two shades of gray. In the environment, that is often the case for the sidewalk, the footpath, where you have got two slabs of concrete that are slightly different [in shade]. And so that is an edge, and we need to be able to detect that, because clearly that has consequences. If you trip on it because you do not see it, you are likely to have a fall. It is not the same as fine detail. It is literally being able to determine shades of gray. It is related to visual acuity, but not exactly the same.
There are other aspects of vision too that are important, like the ability to judge depth. And for that, you need two eyes working together. That is important for looking at obstacles in the environment, and that is also not always detected by measuring visual acuity on the better eye. We really need to have two eyes working together to judge distances and obstacles. So those are the three main things involved. There are other things, like how big our visual field is so we can pick obstacles up. But there are three things that are really crucial for getting around in the environment, the outside environment in particular, avoiding obstacles so we can not trip, not fall.
Editor’s note
The three parts of vision Lord is separating here:
- Visual acuity. How sharply you resolve fine detail. This is what the letter chart at a routine eye exam measures.
- Contrast sensitivity. How well you tell apart two tones that sit close together, such as the edge between two concrete slabs on a sidewalk.
- Depth perception, or stereopsis. How accurately you judge how far away something is, which needs both eyes working together.
An eye exam almost always measures the first. Lord’s research finds the second and third are the better predictors of a fall.
You drew a distinction there between contrast and brightness. What is the difference?
Brightness is just the amount of stimulus. And the contrast is how much they differ when you have got two different points. You could have a very bright footpath, a very bright sidewalk, but very low contrast, if you had two slabs of gray. And contrast is more important than the actual luminance or brightness.
In your experience, do clinicians mostly test acuity and leave the other two alone?
Most optometry services really concentrate on acuity. That is how the tests are designed, to maximize people’s fine detailed vision. It [testing contrast and depth] is often missed. It is only in more research or more intensive assessments that the other two aspects of vision get looked at, which is a pity, because with the aging populations around the world, there are a lot more people who are running into trouble with conditions such as cataract or even just age-related changes. Even when glasses are generally optimal for fine detail, advice to people is also important. If you have got a contrast loss, you just need to be a little bit more cautious in particular situations.
On Why Contrast Fades With Age
It has been a while since I studied the eye. The cones handle color and the rods handle shades of gray, if I remember right. Is that correct?
Yeah, the cones, they detect color. They are really for fine discrimination. The rods are in the periphery, and they are more likely to, you know, you will detect obstacles as you turn your head, then you concentrate on looking at the object with the center of the eye, with the cones.
So what is actually happening? Do rod cells die off, or is it something else?
These changes happen without any manifest disease. This is just what happens with aging, I think. There could be small neuronal loss. Factors such as cataract are a classic one for really exaggerating the effect. If you have got a cloudy lens, it really has a bigger effect on contrast vision, even more on contrast vision than it does on visual acuity. There would be all sorts of subclinical changes like that that just reduce the quality of the image and reduce vision.
Editor’s note
The “cloudy lens” Lord mentions is a cataract. The lens sits behind the pupil and is normally clear. Its proteins begin to break down and clump together from around age 40, and the clumps scatter light instead of letting it through, which is what makes the lens look cloudy. Most cataracts are age-related, but the National Eye Institute also lists eye injury, radiation including ultraviolet light from the sun, some medical conditions and medicines, and previous eye surgery as possible causes for cataract. The institute also reports that more than half of Americans aged 80 and over either have a cataract or have had surgery for one,1 which is why Lord treats it as a routine part of the picture rather than an unusual complication.
Absent a condition like cataract, does ordinary aging affect contrast on its own?
It does, yeah. It is one of the, just like any other functional system in the body, it goes through the same sorts of age-related decrements.
Has anyone worked out the mechanism at the cellular level?
I have not seen any evidence for that sort of level of mechanism. It is mostly been more around the optics, I think. There may be, but I am just unaware of it.
On Depth Perception and the Two-Rod Test
What controls depth perception?
It is primarily two images we get from both eyes working together. It is called stereopsis. By having two slightly separate images of an object, two angles, it allows us to position the object much more precisely than one eye alone. There is a lovely test we do, which is we have people three meters away from two rods. They look through a little window at the two rods, and the rods are on pull cords. And you pull on one, and it will move one of the rods forward and back until you line it up with the other one. It is a real visual, spatial test.
How far apart do you set the rods?
They are 3 meters away and 15 centimeters, or 6 inches. The movable one is either 6 inches in front of or behind the other one. They pull on the cord and the idea is to line them up exactly. Now, a person with good depth perception does that with basically no error. They are just two white rods, looking in a little black box or a window, and they can do it almost exactly. Now, someone with poor depth perception, so not good vision in one eye, might be three centimeters, around an inch, out and sometimes even more. We have had some people who have just moved the rod up and down and not really sure what the idea of the test is at all. So that is really poor depth perception. And then one of the things we do with students, we get them to close one eye. And they are typically then 3 cm (about an inch) out. So that just goes to show the two eyes working together.
Editor’s note
The device Lord is describing is a Howard-Dolman apparatus, and it is one of the vision items in his own assessment battery. NeuRA’s description of the test matches his account: the person sits 3 meters (about 10 feet) back and pulls a cord to slide one rod forward or back until it looks level with a fixed rod, and the leftover gap is measured. Worth being clear about which gap: the two rods sit side by side, and the 15 centimeters Lord mentions is how far the movable one starts in front of or behind the fixed one, along the line of sight. It is a depth offset, not a side-to-side distance, and what gets scored is the depth error still left when the person says the rods look level. We could not find video of Lord or his team running it.
The detail about students is easy to skim past. Those are young adults with two healthy eyes, so they start with near-perfect depth judgment. Cover one eye and their error jumps to roughly what Lord sees in an older adult who has genuinely poor vision in one eye. The second eye, not age, is doing most of the work.
What about someone who only has vision in one eye? How do they judge depth?
There are other cues. They are called monocular cues. An obvious one is someone is in front of the other person. You can tell the closer person because the other person behind is obscured. You can see which finger is closer because you cannot see all of the other one. And other things that you just learn through experience, you know, the size of the obstacle in relation to when they are close and far away. There are quite a few monocular cues. But they are not as good as the two eyes working together.
Is there a normal baseline for a given age, with a range around it?
Oh, yeah, for sure. We have normative data on this. You can see that basically people in their twenties and thirties are all exact and precise. And then with normal aging, it becomes more and more decrements, not big ones, because this is maintained for most people throughout life. But as soon as there is an issue with poor vision in one eye, or blindness in one eye, that will be qualitatively different. They will be an inch, a couple of inches, in error on that test. Very, very different. It is a qualitative difference.
On the Two Ways Poor Vision Leads to a Fall
How do those three aspects of vision actually relate to falls? Is one of them a bigger contributor than the other two?
Yeah, it is interesting. There are two ways poor vision leads to falls. One is inability to detect an obstacle. The other one is we use vision for our balance, even in the absence of obstacles. A classic test for that is you get a person to stand still with their eyes open, and then with their eyes closed. And we can document that by measuring how unsteady they are. Typically, it is called sway. How much we sway over our feet goes up about 30%. So, we use vision like radar. We just look at obstacles, at the walls, and it bounces back, and it helps us position ourselves in space.
If people want to try another test, safely at home, try standing on one leg, eyes open. And do it again with eyes closed. Very few, the minority of people, can stand on one leg, eyes closed, for 20 or 30 seconds. The only difference is vision is removed. So that is really a dramatic indication of just how much we use our vision for our balance.
They are the two mechanisms. Failure to detect obstacles, and just not having that same amount of control. Where that comes into play is when people are on more uneven ground, something soft, something unstable. That is where we really use that vision to help our balance as well. That is why people might fall. The tests we found to be more predictive have been the depth one and the contrast one, over the visual acuity one. They are the key ones. The ability to judge distance and to detect contrast of obstacles like curbs, gutters, pipes and cracks.
Editor’s note
Two separate routes from poor vision to a fall:
- Obstacle detection. You do not see the curb, the crack or the step, so you catch a foot on it.
- Postural control. Vision is a balance input in its own right. The eyes feed the brain a running read on where the body sits in space, even when there is nothing to trip over. Take that away and sway rises.
The second matters most on ground that is uneven, soft or unstable, where the other balance systems have less to work with.
On Multifocal Glasses and the Case for a Second Pair
The convention is still to test acuity alone. Is that a gap in the available tests?
The tests are there. It is the way glasses are designed, to maximize visual acuity. So that is why, and that is basically the way the tests are done. But yes, there is more information that certainly could happen. I mean, the other aspect about glasses too is the type of glasses people wear. Multifocals, or PALs [progressive addition lenses], are a compromise, trying to get vision at different levels of the glass, the pair of glasses. And we found that regular multifocal glasses wearers are more likely to fall than those who wear single lens glasses when they are outside.
Editor’s note
Multifocal is the umbrella term for a lens that corrects more than one distance in a single pair. Bifocals and trifocals do it in visible steps with a line; progressive addition lenses, or PALs, do it as a gradual ramp with no line. The American Academy of Ophthalmology describes the difference as steps versus a ramp. Either way the lower part of the lens is ground for reading distance, which is the part of the lens you look through when you glance a few steps down the sidewalk.
Even while they are wearing their glasses?
That is right, and that is because the lower lens of the glasses is designed for reading, not for walking. When we walk, we typically look two steps ahead, two to three steps ahead. We do not look at our feet, we look two steps ahead. And when you are looking through your multifocal glasses, you are looking through the section that is designed for 60 centimeters (around two feet). So, vision is a little bit blurred. That is the other aspect. We have published on that and even completed a randomized control trial where regular multifocal glasses wearers had a second pair of glasses, just single lens, wore those outside, and they had a significantly lower rate of falls over a year.2 It is another factor. It is more than just fixing one aspect of vision. It is considering maximizing your vision when you are outside.
Editor’s note
The trial Lord refers to is the VISIBLE randomized controlled trial, which followed 606 regular multifocal wearers for 13 months.3 The result is more specific than a headline can carry, and Lord makes the distinction himself in his next answer. Across the whole group, falls dropped by 8 percent, which was not statistically significant. The significant reduction, close to 40 percent, was in participants who regularly took part in outdoor activities. Among those who rarely left home, outside falls went up.3 The practical read is that the second pair is not a neutral precaution to hand every multifocal wearer. It helps the people who actually get out, and for someone who mostly stays in, it made things worse. That is the same split Lord draws in his next answer, and it is why he frames the advice around how active a person is rather than around the glasses on their own.
So for those people, based on your data, it sounds better not to wear the multifocals outside.
A second pair. This is for people who regularly go outside. People who generally stay at home, if they are older and frail, multifocals are an advantage, because you only have to have one pair of glasses. But if you are active and out and about, negotiating stairs in particular, because you really need good vision going up and down stairs. Some people with multifocals take them off when they go downstairs. So, then you are going down with no glasses at all, which as you can see that might be an issue as well.
On Walking Speed as a Screening Test
I read the abstract of a recent review of yours comparing walking-speed cut-points. You found that 1.0 meters per second picks up more future fallers than the 0.8 figure that has been widely accepted. What did you find?
Why we did the review was just to contrast the two cut points. And one meter per second is considered, you know, often like the speed you need to cross the street safely. It is not a fast walking speed. Young people can walk at, you know, like, 1.2, 1.4 meters per second. I think the issue, what we found is these studies were done in people who are living at home, not in institutions, not under care. If you are living at home independently, a lot of people are faster. So, 1 meter per second was more the sweet spot for determining who was at risk of falling versus those who were not. So people who are slow walkers, slower than one [meter per second], were at increased risk. So that is probably, you know, that is not over surprising, that slow walking is an indicator of frailty and lots of other poor outcomes. Also related to falls. 0.8 was just too low to discriminate. Too few people walked slower than 0.8, that is the reason why. It was only the slowest versus all of the rest, versus a better cut point for discrimination.
Editor’s note
The review Lord is describing was published in 2026 and pools individual participant data from 28 studies and 7,608 people, split into eight studies of community-dwelling older adults (n = 3,627) and twenty of clinical populations (n = 3,981). That split matters for reading the figures below, because the two groups fall at very different rates and the cut-point behaves differently in each. He is the review’s corresponding author.4 Some background on the question is worth having. Gait speed here means a short timed walk converted into meters per second, used as a fast screen for who is likely to fall. The 0.8 m/s line came from the World Falls Guidelines, published in 2022 by an international task force that Lord himself sat on.5 Going back over the pooled data, his group found that walking below 0.8 m/s was associated with a higher risk of falling, a relative risk of 1.27, and a higher rate of falls, an incidence rate ratio of 1.54. As a standalone screen, though, its accuracy was modest: 58 percent overall, with 77 percent specificity and 35 percent sensitivity. A 1.0 m/s line produced similar effect sizes and similar accuracy but flagged far more of the people who actually went on to fall, 30.1 percent against 8.7 percent among community-dwelling older adults and 66.9 percent against 46.0 percent in clinical groups. The authors land on both halves of that at once: slower walking is reliably tied to a higher risk and rate of falling in community and clinical groups alike, discrimination is poor either way, and the 1.0 m/s line is the more clinically useful of the two precisely because it catches more of the fallers. That is the trade Lord describes next. Not a sharper test, a more useful one.4
Was 0.8 previously an accepted number, or was that something you set for the review?
It was included in the World Falls Guidelines, and that is why we did this work, because we looked at what we thought was in the literature, that it was too low. I was part of the World Falls guideline. I was part of the decision making, but it just went through as, I guess it was conservative, you know, just making sure that people below that would be at increased risk. It was done by consensus, rather than by looking at all the available data, and the point of the paper was to just check to see if that was the case or not. And it looks like, if you are looking at people who are independent in the community, one meter per second is a better cut point for looking at increased fall risk.
What was the resolution of the comparison? Did you test 1.0 against 1.1, or 1.0 against 1.5?
We tried some other ones, but they were the accepted ones. What happens is, you know, if you keep changing your criterion, your prediction gets either better or worse as you go along, so it is called a sensitivity-specificity trade-off, and so more false positives and more false negatives as you keep changing it as you go along. One was about the sweet spot, actually. It was a good point to pick.
How did you measure fall risk against walking speed? Was it the number of falls?
Yeah, so all of the studies that we reviewed would have administered the test to people, and then the gold standard approach is to follow people up for 12 months with regular surveys, either weekly or monthly surveys, so you can hopefully document the number of falls people have. And this was simply whether people fell at all in that follow-up year, yes or no. That is how the test was done.
Some people naturally walk slowly. Have you found people below 1.0 meters per second who are not really at risk?
For sure. I mean, if you are slow, it is not a 100% chance of falling at all. It is just your risk. But there would be the people in those slow walkers who are steady. They would be slow and steady. They are winning the race, and they would be fine. But it is a marker of many things, you know, like reduced vigor, strength, balance. So overall, in population terms, you are better to walk more quickly. And in some of the work we have done, it is actually quicker and steadier are the ones who are really at the low risk. You are walking fast and also smoothly and steady, with the accelerometer signals there. That is the safest.
On Measuring Gait From the Wrist
Another line of work of yours is digital gait biomarkers. Can you elaborate? Is this still under wraps?
Yeah, sure. What we call the digital gait biomarkers are ways of measuring different aspects of gait or walking quality. So, the speed in which a person walks, the amount they walk, and also the quality of the walk, their symmetry, their regularity, their smoothness. How it works, it is by looking at sensors, so basically measurements of acceleration called accelerometry. This technology has been around a reasonable time now in measuring gait and performance, but it all came out of airbag technology, actually. That is when the accelerometers became not overly expensive. They literally went from thousands of dollars to, you know, a few cents, I think, that were produced in such a massive number. They can be put in inertial measurement units, they are called, or accelerometry, just into a tiny matchbox-sized device.
Is that the same technology smartwatches use?
Yeah, they are now in smartwatches too, and they have evolved also out of pedometers, you know, simple pedometers that used to just measure single steps, and give you a step count. They have evolved from that, but now, because you have got measurement in three dimensions, forward, back, up, down, sideways, you can get a lot more information from the modern accelerometer. These can be placed on the legs or the back, and they are good places, because they give you direct measurement about movement of the body. But the work that we have been doing has been putting this on a wristband, so similar to a watch. That has big advantages, because it is much more acceptable to people to wear something like a watch than it is to wear something around the leg or around the back.
The bit of the breakthrough was because the disadvantage of the watch, of course, or the wristband, is that the arm moves around much more than the body does. There is lots of noise that is not related to your walking. The PhD student who worked on this, Lloyd Chan, did a whole lot of validation work, where he looked at the accelerometry signals at the same time while he videoed people doing all different types of activities, and different placements of their hands, such as, you know, like, if they had their hand to their ear, or their smartphone in front of them, or if they were texting, running, hands in pockets. And he has been able to remove the noise, and therefore get really useful information from a wristband. That means you could measure people’s speed, the amount of steps they do, their longest walk, you know, all these sorts of aspects if they have been running. And also when they do walk, how smooth or regular the walking pattern is. They are useful domains.
Step two was to use a very big database. There is a big one called the UK Biobank, which has literally hundreds of thousands of people. They also wore the same watch. We used that data and Lloyd’s algorithms to predict outcomes. It predicts people who are likely to be admitted to a hospital because of a fall. But it also identifies people who might meet the criteria for frailty, but also other conditions as well, like stroke or diabetes or heart disease.
Editor’s note
UK Biobank is a long-running study of roughly half a million UK adults. It is best known for genetic and molecular data, but it also ran a movement substudy: about 103,000 participants wore an Axivity wrist accelerometer continuously for seven days. That substudy, not the molecular data, is what Lord’s group used. The algorithms he describes were developed and validated against a week of wrist-sensor data from 78,822 of those participants.6 Applied to that cohort, they have since been used to predict injurious falls, in an analysis that narrowed the sample to the 32,619 participants who were 65 or older and living in the community and followed them for up to nine years7 and to identify frailty in middle-aged and older adults.8 The wristband is a research instrument. It measures and predicts, and it does not call anyone, which is a different job from the one a medical alert system does, which is to summon help once a fall has already happened.
Is that all from gait, or are there other inputs, like heart rate and the other things smartwatches measure?
It is interesting, this work follows on from other work which has shown that clinically measured gait, just when you test someone’s gait in the clinic, it predicts these same outcomes too. You know, it is very, very prognostic for, you know, how long a person will live. The advantage in doing it this way is you do not have to have someone come in. If you wear the watch for a week, you get these parameters, and therefore it is remotely, automatically measured, and from a wrist. That is the advantage in doing it this way. But good point about, the measures do predict these outcomes, but then you can also add it to other predictors like risk factors for, like, blood pressure and so on, and they add to the discrimination.
Is it a watch, or something else?
It is actually a band. The big issue is battery life. So, if it does not have a face and do all the other things that the smartwatch does, it will last a whole week. It takes less than half an hour to charge, about the same as a watch.
On What a Week of Ordinary Walking Reveals
So if someone wears this and the prediction says they are more likely to fall, or at risk of high blood pressure, what happens next? Do you send them recommendations?
Well, that is the next step, and that is where we are trying to work, actually, with companies and so on, to actually incorporate these algorithms into their products. What it would mean would be, it gives you that information early, because a lot of these conditions, there is a lot you can do. Like, obviously, you would really look at the management of people who are at risk of stroke in the next nine years. Or another one we have looked at is chronic obstructive pulmonary disease. It predicts that too, so you can see why it might be that people are starting to slow down, get less regular in their gait, and so on. And there are all sorts of pharmaceutical and non-pharmaceutical treatments you can do for such conditions. That is the idea. It would be early intervention. And really try and, you know, prevention, like true prevention, just because we might be picking this thing very early on.
Editor’s note
Lord’s claim here is stronger than “sick people walk more slowly.” He is saying the conditions leave different signatures in the wrist data. The mix of measures that flags someone heading for a stroke is not the same mix that flags chronic obstructive pulmonary disease, and neither is the same as the mix that flags a fall. A few measures do recur across them, and the one he keeps returning to is the longest continuous walk a person takes in a week rather than the total step count. That is what makes the approach a screening tool for several outcomes at once rather than a single crude index of frailty.
Do you have a patent on it?
No, not so far, no. We have got some preliminary work being done here in Australia along those lines. And yeah, that is what we would really like, of course, because there is no value in doing this research in a health-related area just for the sake of it. If it does get a practical use, we are all for it.
Using your COPD example, is the pattern of someone who gets winded and slows down different from the pattern of someone who is weak for another reason? Can you pick up those small differences?
The patterns for each of the diseases and conditions we have looked at are not always the same. Some key factors keep coming out, and one of the strong ones is the longest walking bout that the person has done. It is more than step counts. If people have a longer walking bout, they are protected. The people who never go out for a walk, or, you know, like, half a kilometer or whatever, half a mile, they are the ones who are likely to, it is a consistent risk factor for adverse outcomes. It is an important one. Usual or fast walking speed is often useful. For some, it is interesting, because this is a community sample age 55 and over, but any amount of running is protective. So just if people run at all, it is protective.
Even a minute of running?
Yeah, so it has just been categorized as any running. It has got a very sort of, like, skewed distribution. Most people did not run. But for those who did run, they were better off, and lots of outcomes. A lot of these things are chicken and egg. But if people are running, keep doing it.
Editor’s note
The pattern Lord describes here holds beyond falls. In the same wrist-sensor cohort, walking speed, running duration and the proportion of longer walking bouts predicted cardiovascular death, and the authors concluded that these features add information that a daily step count on its own does not carry.9
If you are a slow but steady walker wearing the device, it picks up more than speed.
Yeah, exactly. Exactly. It would pick up the smoothness of your gait, which would be the steadiness. It would pick up the number of steps you did. And the longest walking bout, all of those things, and they are equally protective.
On the Physiological Profile Assessment
The point of falls research is prevention. In 2003 you published the Physiological Profile Assessment. The idea is that it tells you how likely you are to fall, and then produces recommendations. Is that right?
Yeah, I mean, a lot of the things we have been talking about are included in the PPA. Visual tests, for example, the contrast test is in there. The test of lower limb sensation, which measures neuropathy, or, you know, just even subtle loss. A measurement of strength in the legs, the quads, which is one of the most important muscle groups. The test of speed, reaction time, and that is a finger press in response to a light. And a test of balance, and it is a test of balance when people, how steady they can stand on a foam mat. All of the types of things we have talked about already are in the PPA.
Way back in that time, we put hundreds of people through these tests and then we followed them up for falls. And they were the five most, you know, independent and significant discriminators. And then if you put them all together in a statistical function, you could predict the likelihood that they would fall into the future. And they were the key ones. And from that, you can see that you have got information as to why people might be falling. It is their vision, the loss of sensation, they are weak, they are slow in their responses, or they have just got bad control. That then produces a report for people and gives them the appropriate advice as to what to do to reduce the risk.
Editor’s note
The five components are set out in the 2003 paper describing the approach.10 The vision test in the profile is edge contrast sensitivity, not the letter chart, and the depth-perception task Lord describes above is the rod-alignment test used alongside it.
What the assessment actually measures:
- Vision, tested as edge contrast sensitivity rather than a letter chart, alongside a depth-perception test.
- Peripheral sensation in the lower limb, covering proprioception, touch sensitivity and vibration sense.
- Lower-limb muscle force, with the knee extensors carrying most of the weight of the score.
- Reaction time, measured as a finger press in response to a visual cue.
- Postural sway, measured while standing on a foam mat with eyes open and closed.
Combined in a single function, the five produce an overall fall-risk score and, more usefully, a profile showing which of the five is the person’s weak point.
My understanding is that the PPA is available worldwide.
It is, yeah. It has been used in research and clinic labs around the world in that time.
Can someone walk into a doctor’s office and ask for it?
No. It still has not had massive penetration, but it has been taken up by various individuals, some physiotherapists, some rehabilitation sites. Many universities have used it in research and so on. But yeah, it is still available, though, through NeuRA, where I work.
On Training Balance With a Dance Mat
You also work with people who have various neurodegenerative conditions, chemotherapy-related neuropathy, and cognitive impairment. Is that a catch-all, or did you pick those conditions for particular reasons?
Yeah, all of the conditions we pick affect gait quality, and they increase your risk of falling. The groups we have looked at have all got a balance problem. MS, stroke. We have looked at studies of people with dementia, and also Parkinson’s disease. But the interesting one that we are looking at, at the moment too is the chemotherapy-induced neuropathy, because that can be people much younger. But it has a big effect, not only on the loss of sensation, but on balance and gait quality. And it also affects the hands as well. It is definitely a major complication of the treatment.
What we are putting in place there is an intervention to try and improve balance and balance control. And in essence, it is really sort of like, you know, Dance Dance Revolution, StepMania-type dance mat training. We have done quite a few interventions using this game now, and it is designed to train up quick and accurate stepping. You can imagine those games, and we get people on a dance mat at home, either watching a screen or their TV, playing adapted games, you know, such as Dance Dance Revolution, or moving their feet to play something like Pac-Man, or Space Invaders, or Tetris, all these sorts of games. They require quick and accurate steps. You also need to withhold your step. And you also need to make decisions, so it is testing your cognition as well. It is testing two things, not just your stepping, but your decision-making as well. That is what we are doing at the moment to try and make exercise fun.
Do you have a resource online for people outside Australia?
My colleague is looking after this. I suppose if you looked at our NeuRA website, if you Google that, you would find it. Through NeuRA, you will get an indication of the research we are doing, and the assessments we do, and so on.
On the One Thing to Ask an Optometrist
Coming back to vision. Contrast and depth are not measured as often as acuity. What should someone say to their optometrist to make sure those get tested?
I think the more important one would be to get advice. You know, if a person is active, still working in the community, and they have tripped on an obstacle, for example, to ask their optometrist about a separate pair of single lens glasses. I think that would be the simplest thing to do. People who are noticing that they are having difficulty focusing on things when they are out and about, walking down steps, stumbling, hitting things, that is probably the people who should talk to their optometrist about trying a second pair of single-lens glasses. You do not give away your multifocals, because they are really useful when you are in the house. When you are driving, you need them to look down at the dash, back up again. All of those things, they are useful when you are in a safer environment. But where they led to falls was when there were people in lesser known environments. So when you could not anticipate the tree root, you could not anticipate the pavement crack, et cetera. That seems to be, I think that would be the best advice.
Editor’s note
Lord’s closing advice is about staying active outdoors rather than staying in, which is also how he frames the rest of his work: measure what is actually driving the risk, then change that one thing. For seniors who want that independence along with a way to call for help if a fall does happen, a mobile device with automatic fall detection covers the same outdoor settings he describes, the unfamiliar pavement and the tree root you could not anticipate.
References
- Cataracts | National Eye Institute. https://www.nei.nih.gov/eye-health-information/eye-conditions-and-diseases/cataracts.
- Lord, S. R., Dayhew, J. & Howland, A. Multifocal glasses impair edge-contrast sensitivity and depth perception and increase the risk of falls in older people. J. Am. Geriatr. Soc. 50, 1760–1766 (2002).
- Haran, M. J. et al. Effect on falls of providing single lens distance vision glasses to multifocal glasses wearers: VISIBLE randomised controlled trial. BMJ 340, c2265 (2010).
- Hicks, C. et al. Predictive accuracy of gait speed for falls: An individual participant data meta-analysis. Ageing Res. Rev. 120, 103207 (2026).
- Montero-Odasso, M. et al. World guidelines for falls prevention and management for older adults: a global initiative. Age Ageing 51, afac205 (2022).
- Chan, L. L. Y., Choi, T. C. M., Lord, S. R. & Brodie, M. A. Development and large-scale validation of the Watch Walk wrist-worn digital gait biomarkers. Sci. Rep. 12, 16211 (2022).
- Chan, L. L. Y., Arbona, C. H., Brodie, M. A. & Lord, S. R. Prediction of injurious falls in older adults using digital gait biomarkers extracted from large-scale wrist sensor data. Age Ageing 52, afad179 (2023).
- Osuka, Y., Chan, L. L. Y., Brodie, M. A., Okubo, Y. & Lord, S. R. A Wrist-Worn Wearable Device Can Identify Frailty in Middle-Aged and Older Adults: The UK Biobank Study. J. Am. Med. Dir. Assoc. 25, 105196 (2024).
- Herrero Pinilla, B., Hong, S., Brodie, M. A., Lord, S. R. & Chan, L. L. Y. More than step counts: Slow walking speed, limited running, and fewer long walks predict cardiovascular mortality in the Walk Watch UK Biobank study. The Journals of Gerontology: Series A 80, glaf184 (2025).
- Lord, S. R., Menz, H. B. & Tiedemann, A. A Physiological Profile Approach to Falls Risk Assessment and Prevention. Phys. Ther. 83, 237–252 (2003).
Dr. Eliezer (Eli) Lichter
Dr. Eliezer (Eli) Lichter brings a rare combination of hands-on clinical experience and rigorous scientific training to his work as a medical writer at Medical Guardian.
Before entering research, Eli served as an emergency medical technician in Yonkers, New York, one of the state’s busiest urban EMS systems, where he was recognized with multiple Lifesaving Citation Awards. That work put him on the front lines of exactly the crises Medical Guardian exists to prevent, including fall responses involving older adults. He later served in an administrative role at a large skilled nursing facility in upstate New York, where he managed the full operational complexity of senior care, including fall prevention protocols and incident response.
That direct, real-world exposure to what aging adults and their families face every day shapes everything he writes.
Eli earned his PhD in Biochemistry and Molecular Biology from the University of Nebraska Medical Center, where his research focused on the genetic mechanisms underlying neurodegenerative diseases, including Alzheimer’s and Parkinson’s disease. He then completed postdoctoral training at Boston University in computational biomedicine, including a research affiliation with the Broad Institute of MIT and Harvard, developing molecular and computational strategies for early detection of cancer, Alzheimer’s disease, and other serious conditions through advanced applications in genomics and epigenetics.
At Medical Guardian, Eli translates complex medical and scientific research into clear, trustworthy content that helps older adults and their families make informed decisions about their health, safety, and independence.
