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SA: Hello, and welcome to Master the MRCPCH. In this series, we tap into the expertise here at Great Ormond Street Hospital to give you an overview of a topic on the RCPCH exam curriculum. So whether you're revising for an exam or just brushing up on a need to know topic, hopefully this podcast can give you the information that you need.
I'm Dr. Sarah Ahmed, a paediatric registrar and the current Digital Learning Education Fellow here at GOSH.
In today's episode, we're going to be talking to Dr. Eleanor Yule about visual impairment in childhood. Dr. Yule is a consultant in paediatric neurodisability at Great Ormond Street Hospital. This topic corresponds to learning outcomes in the neurodisability and ophthalmology sections of the MRCPCH exam curriculum.
Eleanor, thank you very much for talking with us today.
EY: Oh, it's a pleasure. Thanks for having me.
SA: So before we start talking about visual impairment in childhood, I wanted to ask, what would you like people to get out of listening to this podcast?
EY: So what I really think I would like trainees to get from this resource really is the beginnings of demystifying their approach to children who've got a sensory impairment, because I'm really aware that certainly for me, both as an undergrad and a trainee, until I started working in neurodevelopmental paediatrics had quite limited resources to draw on that would help me work out how to approach and get to know these children who've got sensory differences and developmental differences. And then on top of that, as well as just having an approach in establishing a rapport, trying to get a sense of where they're at, both with their functional vision skills and with their general development. And you do an awful lot of that through play. So that's what I'd really like. And then also to help get some confidence in when you're interpreting measures of visual acuity, what that might actually mean for a child. I think that'd be incredibly useful.
SA: Yeah, absolutely. Just echoing what you said, you don't really, you get taught it, but you get taught it in kind of very broad strokes. And it really is through experience and things like this actually, that you get a better understanding. So yes, I think this is going to be a really helpful episode.
So if we're starting to think about visual impairment, what does that mean? What causes children to have problems with their vision?
EY: Great. So you're asking about what are the definitions and then perhaps what are the aetiologies? Is that right?
SA: Yes.
EY: That's a good place to start. So it can be tricky actually in childhood, because if we think about definitions of impairment, the WHO classification, World Health classification and ICD 10, they all rely on distance acuity. And actually for children, we're not often interested in or able to measure what they can see at three meters, certainly not for the early years. But it's worth just revising those the way it's broken down. So definition wise um, the WHO based definitions, they categorise into normal, mild, moderate, severe, and they use the term blind, though you may see now instead severe sight impairment or profound. And they map those onto logMARs. So the, the logarithmic measure of the minimum angle of resolution, but so that's the sort of universal language we should be using when describing an acuity measure. The clue’s in the name, it's a logarithmic scale where zero is normal vision. So what you might call 20, 20, but again, we're not measuring at 20 meters for children. And then logMAR one is 10 times worse. So what you might used to have seen as six over 60 in Snellen's. And remember that certification of sight impairment is not about a measure of acuity. That is a process that's done via the eye clinic. It's a registration with local health services that helps map needs of children in a given area. If you're registered, it helps local authorities plan the resources they can allocate to someone and certification’s done at the discretion of an ophthalmologist. There are certain criteria that can be met in terms of acuity and monocular or binocular vision losses that they can register for. It's not the same as a measure of acuity, so it really shouldn't appear on a medical profile list or a diagnosis list, but it's useful to be aware of for some families.
So that's a little bit about definitions really and they're very easy to look up. If you just Google the WHO classification system, you can look up where those thresholds lie. Something that's worth knowing is moderate vision impairments are from like 0. 5 to 1. And severe is from one and above, and really if you've got logMARs of one to 1.3 and above, that's what we might call a profound visual loss. And certainly people would be expecting to be more tactile than visual learners. But as I say, it's not that simple because these aren't measures for children in the near field, which is where a lot of your learning happens.
SA: Can I ask, but
EY: Sure.
SA: What is the difference between acuity and refraction or refractive error?
EY: Oh, absolutely. So they're measuring different things. So this is, again, it comes back to a lot to communication, doesn't it? Because families can often come out of eye clinic or come out of seeing the orthoptist and know what glasses their child needs, but perhaps not have a clear understanding of how blurry the image is that their child can both see and make sense of and attend to. So refractive error is it's the physics of how images are focused on the back of the eye. Yeah? So that's the measure you get for what prescription of glasses you need. So that's done by the orthoptist or the ophthalmologist working with them in the eye clinic or in the high street optician. So you've got long sightedness, short sightedness, and that's to do with the the mechanical problem of the image not being focused appropriately by the eye's lens on the retina in order to give a clear image. And that's where the glasses correct. Whereas acuity is the degree of fine detail that could be discriminated by an eye once that image has been as focused as best it can. Yeah? You're really interested in someone's acuity with their glasses on because, glasses do not fix all vision problems.
SA: Okay. That's really helpful. Can, can we talk a little bit about what conditions, so the aetiology, so what conditions would cause a child to have problems with their vision?
EY: Yeah, absolutely. We could talk about sort of broadly breaking things down where in the eye or the visual pathway, there's a problem.
SA: Yeah.
EY: Some of the most complete and reliable data on what's happened in Britain came from a really good epidemiological study that, I can't believe it's 20 years old now, but it's really available as Rahi et al, R A H I, who broke down in terms of things happening in the anterior part of the eye, so parts of the eye that aren't the retina, issues with the retina, issues with the optic nerve and chiasm, and then issues with the, the parts behind that. So brain based visual problems.
So in the UK about 40 percent are brain based and then about 20 to 23 were in the nerves, the optic nerves and chiasm. About a quarter is retinal diseases and then the rest is made up of things like congenital glaucoma, cornea problems, lens problems, whole globe problems, so the mycopthalmias. And it's worth knowing that actually the incidence, by the time you're 16 years old, it's a bit higher. So that reflects the acquired brain based problems for the most part.
SA: Okay.
EY: It's worth remembering that, you know, in the UK, severe sight loss is a relatively rare issue. And then like globally it's unfortunately not, and it's unfortunately not due to quite preventable causes. So in the UK, we've seen a lot less retinopathy of prematurity and a lot less congenital cataract and also with early screening, a lot less long standing effects from congenital cataract. A lot less brain based and eye problems from congenital infections, such as rubella, though some do persist, such as CMV. And we're seeing a lot more strongly represented the brain based visual problems, because it's both the bigger proportion of what's happening now, but also our increasing ability to recognize the visual problems of children who've got general brain issues, issues with development.
SA: It is quite a large spread, isn't it? It's, and it's really interesting to think about it from what happens in the UK versus what happens globally as well. And I suppose that's, like you said, it's because of interventions like doing NIPES and checking for red reflexes on day one, which is why we have so fewer of these other things.
EY: Yeah absolutely. It can really just remind you how important those newborn exams are. You know, in the UK, we have quite a few moments in childhood where we're screening for vision problems, some are more focused for some children, you know, for example, the more focused follow up for children with Down syndrome, because we know they're more likely to have issues with squint, strabismus, and also cataract. But then the more standardized points where we screen children and the focus screening for retinopathy in premature babies and low birth weight babies.
SA: So thinking a little bit about those screenings and the examinations that you do when you're faced with a child that you're concerned might have problems with their vision. What, what is your approach to examining these children?
EY: So I think much like anything to do with child development, you can learn an awful lot just by watching before you even start to present things to it to try and interrogate vision as it were. And also it's always preceded by a decent history from parents, because getting a sense of at what point parents were first concerned and where they've been on that journey of having their concerns considered is really important and really important for a family's experience, because if they are listened to and understood, they're going to, I believe, much more readily trust your opinions and what you're noticing about their child. As you can imagine, that's really sensitive conversations.
So in little ones, really, we've got, you know, the physical examination, where you just want to get an idea, is there more general developmental impairment going on? Have they got normal tone and power? Is their head well grown? Plot it, measure it. Any other subtle differences in their appearance and what do we know about their hearing.
And then coming on to vision, just closely watching seeing what might be happening. There are, if we break down even further before we can even do measures of acuity, we can get an appreciation of what size of an object a child can visually detect and fixate on. And that's really worthwhile understanding. It's very hard to map these things on to measures of acuity because you're not making a measure of a discrimination between 2 parts. That's what acuity is. It's more, you're measuring the ability to detect a single thing. So we do have measures of this detection vision that starts with gross detection. So is there light perception? Is there an ability to fixate on that light and turn to it if it's presented in different places. And then we use lures of decreasing size. So, generally speaking these can be mapped quite, quite carefully in the first year of life, and we expect someone who's, by the time they're nine months, to really be able to fixate on something the size of a sprinkle that goes on a cake, and we would generally say if you can fixate on a two and a quarter centimeter cube, so like a little wooden block, that's quite good detection vision, and you're likely to have the ability to be, you know, reaching out for things in space and making sense of things presented to you in the near field to the best of your other abilities.
So that's detection vision and gross detection. And, you know, when you're measuring any of these things, you've got to be really aware of the rest of a child's developmental profile.
SA: Yeah, absolutely.
EY: It's particularly with brain based, visual problems in, you know, children who have cerebral palsy or some other global difference to their brain, that anything you interpret has to be with real caution because you're relying on a child's ability to fixate on something that can be, you know, an image has been made on their, the back of their eye. Are they able to then attend to that image? Make sense of it somehow and find it, you know, interesting and important to attend to. So those are factors at play there.
When we're measuring acuity with sort of the next stage of interrogation, as it were, and these things that you'll see both in the neurodevelopmental clinic and in the eye clinic, it's measures of acuity where we rely on the fact that you don't have to be motivated to look at something in particularly. If your eyes can visually discriminate some stripes on a blank card, then naturally they're just drawn to them. Your eye recognise a pattern and, and they go that way. So, that's the measures of, of what we call grating acuity. So stripy cards, and then some cards with vanishing, more faded optotypes of, of little images, like a train and a boat and a car. That's a different set of cards we sometimes use. But again, you don't have to know it's a car or a train or something. It can just be a little bit more motivating for the slightly older preschoolers to get them sitting and having a one on one moment with you.
And then with the older children, it's recognition acuity where you're doing either shape matching. So you don't even have, you know, they don't have to have the words for it. They just have to have the ability to go with the concept of matching. Yeah, so that's a bit of a breakdown of how we might measure recognition acuity and the resolution acuity and another little important caveat would be that resolution acuity can sometimes be a little bit of an overestimate. So they sometimes don't map exactly and you might get a lower recognition acuity. Just to be a little bit aware of that, but it is as with any of these, we, we think it's just worth trying to gather all that information to the best of your ability.
SA: Can we talk, you mentioned this earlier, but vision is so tied up with other aspects of development. Can you tell us a little bit more about that?
EY: Yeah, absolutely. And I think it comes back to, that's why we're making such a strong point about you can't, you can't comment on a child's development if you don't know what's happening with their vision, because that's a really important context. So really in the first year of life visual sensory input for typically developing children is the major impact on how you start to make sense of the world. Any sensory input is how you sort of progress with your development. Information goes in, you process it and make sense of it and react to it, and then learn that you can have some agency over what's going on in the world around you. And it's the visual side that really predominates for the majority of children who are developing typically. So that's why it's so important. And we need to think about these sort of cycles of development that go on, the more input is received. So a typical developmental trajectory will look different if you're growing up with visual impairment. So if you had a purely vision impairment issue, no other issues with other areas of your brain or your movement or your general health, you will still look different in the way you acquire your language skills, your motor and mobility skills, your social emotional skills, and how you learn to make sense of what's going around you with your cognitive skills and how you learn to perform in your environment with your adaptive skills. They're all going to be done differently. And the other sort of thread alongside that is unless you get the right support in and the right understanding of what a child needs for their next step at each step, having profound vision impairment, having no formal vision, no objects that you can slightly make sense of to reach out to, it's a potential developmental emergency more than anything, because without ways round, without ways of mitigating for that missing information about the world through your other senses and through play partners and learning partners, you're not going to get the drive, those cycles of development that you need for the brain to keep growing and learning.
So thinking about how visual impairment does affect the early years of development, if we think about how you know where you are in the world and how you take in information about what's going on in your immediate vicinity. Think about a baby lying in a crib with a mobile above them, and they notice shapes and they notice their hands and they notice that they can move their hands out to cause a difference in that shape and grasp that shape and begin to make sense that there are things beyond their body, basically. That beginning of understanding has to be presented in a slightly different way for children who are not seeing these objects around them. So there are some important potential stumbling blocks in that process if it's not supported. So sometimes children who are reluctant to use their hands to explore the world or are hesitant to experience things in their hands, if these children who are visually impaired are in that situation, that's a real challenge. And it's not insurmountable. But it's something that's worth being aware of early. And also worth respecting what's happening with a child's hands if they're learning with low vision, because directly placing something into a child's hand without them having any choice or agency in that or any forewarning as well of what's going to happen can be incredibly overwhelming. It's not that they feel more than people who, you know, have got vision, you know, it's not that that myth that there's a super sense, but it's more, there is no choice in it. A child who reaches out and grasps an object has, you know, there's choice there, so we have to be really careful about how we present materials to children with visual impairment. You can generally do that by gently presenting onto the back of the hand, making them aware of it, or younger, younger ones on, on their body. See if they then make that choice to bring their hands in. And then if they may remain quite reluctant, there are some different techniques you can do to gently guide them, by the elbow, to start to engage.
So that's sort of hand use. And then there's things about, you know, your position in the world in general, you can't see the floor, you can't see an adult tapping on the floor in front of you or smiling at you in tummy time. So you have to sort of learn about your position in space in a slightly different way, in a facilitated way, again, through like gentle guiding about knowing where, where you are in space, on the floor, on a person's lap, bringing, bringing games and song into it to get a little one used to having their, their body in different positions and knowing where the floor is.
But you can have what could be interpreted as delays in manipulation of objects and delays in the gross motor skills, like sitting and falling, standing, walking, when in fact they may be completely on track developmentally, they're just coming at a different interval because of the input to go in to make that next step.
And then it can also, as well as being appear delayed compared to sighted children, it can look a little bit different in the early years. Well, particularly the social and emotional side and the language acquisition. So, if you can imagine, if you're missing out on lots of incidental information around you, when you're playing. If you don't know that another child sat next to you is picking up a different toy, a new toy, and having a really good time with it and smiling and really enthralled by it. How can you make the choice to move on from the toy that you've been enjoying? And how can you trust you're going to have as good a time? So that can then end up appearing to be a bit more rigid in play and a bit more repetitive. And it may not be the case that a child's got an inability to be flexible and try new things. It's just, it's a lot harder for them to appreciate that could be worth doing.
SA: So I get how not being able to see something can affect your gross motor skills, but how can visual impairment affect language and language acquisition?
EY: Yeah. It's to do with what senses have you got to know what's out there in the world? That's worth having words to describe. And then beyond that, beyond concrete things, knowing what's out there in the world in terms of experiences or ways we label people to use language to describe to both label them and then, you know, request. And then comment on and build on. So, it gets harder to link your language to what's happening in the concrete world and harder to appreciate what's different about for example, using pronouns to describe other people, cause you perhaps might be more linked to the experience that's right in front of you.
And there can be a bit more of a tendency to learn language in chunked phrases or, you know, what sometimes is called learned phrases, because when your adults are commenting on the segments of the day, it may be you're picking up on that whole phrase rather than you know, noticing that, you know, the hairbrush, when they say time to brush your hair you're going to perhaps attend to that whole phrase and recognize that's what's said before your hair is brushed, rather than linking, you know, the action of brushing and the noun for hair and breaking it down in that way.
But then that does also lead us onto the fact that as well as appearing different for some children with visual impairment, the whole side of interperson interaction and social skills and joint attention, there is alongside that, that difference which can pan out to be a child who goes on to be an adult who's got quite a range of social skills and a range of ability to have insight into other people's experiences. We do know that there is a higher incidence of children and young people who are autistic with visual impairment. Particularly severe visual impairment, the incidence is up around 20%. So if you just sort of break that down a bit, it's, you know, that whole interpersonal interaction, just, it looks quite different. A parent can notice what a child is attending to, read that, comment on it, and then you help that child link in and notice that someone else is noticing what you're doing and then joint attention builds and builds. So it's not that it can't be done, but it's developed in a different way. But there is an increased incidence as well, eventually having autistic differences. And because of the vulnerabilities and then also the fact that quite typical development for children with low vision can look a bit different, often there is a tendency to do a little bit more careful monitoring and support rather than going for a very early years diagnosis of autism, because sometimes you just need to see what happens when you get those strategies in place.
SA: Can you tell us a little bit about the role of the MDT in looking after these children?
EY: I think that's really important because when we meet children in low vision developmental paediatric service, we're very, very aware that we're one tiny bit of the picture of what's happening to these children out there in the world. There's a number of professionals, I think, as trainee paediatricians, it's worth getting a sense of what they do.
Much like we have teachers for the deaf, we have specialists in education, qualified teachers for vision impairment. They don't just work with school aged children. They can work with families right from the beginning when there's a significant visual impairment to make sure that the early years are well supported and adapted for maximizing learning and play potential and developmental potential for kids who've got vision impairment. Some of them will use a developmental journal, which is a sort of age and stage related breakdown of play-based ideas for families to use to help children come on in all their areas of development. So their communication, their joint attention, their movement and mobility. And it's really practical and really evidence based developed here in the UK by professionals, some of whom work in the vision clinic at GOSH. And it's really useful thing to work through together with the family and gives good ideas if, if you're a bit stuck at any particular area, other things that you could try.
You've also got alongside teachers of vision impairment, you have habilitation specialists, sometimes they come through third sector, such as through guide dogs. Sometimes they're through education and they are for the children who are becoming mobile in their environment, making sure that they've got access to the skills and the equipment they need to develop their independence, getting around their environment and doing things for themselves.
And then also the VI teachers, once you are school age, making sure that curriculum is accessible and presented in an equitable way as much as possible. So sometimes that's through enlarging, alternative visual materials, so things like iPads and magnifiers, audio descriptors, and then also the braille skills.
SA: It's so important, I think, like you've said, to have a good team around and to recognize it and then to support these children so they can get best out of their education. And so the work that you guys do and the work that the wider MDT does, I think it's just phenomenal.
EY: I certainly enjoy it. I enjoy playing our small part. Often, it can be very confusing as well for, you know, I'm thinking as a trainee, getting my head around child development in general, making assessments of development in a child who's got no developmental differences or vulnerabilities. That was hard enough. Fine motor assessment. Oh gosh, have I, have I got everything I needed? Have I asked questions about language? And then doing it in the context of a really important difference and begin to develop a bit of confidence in when someone's on track or not. I find that really fascinating but really worthwhile as well often to provide some reassurance that things are going really well for families and they're doing an awful lot and families often just need that bit of validation that they can get to know their child and interact with them and have fun and teach them. But then also to highlight the children who really are going to benefit from more intensive support to move through their development to the best of their ability.
SA: Yeah, I couldn't agree more. Um, let's wrap up with some quick fire questions. So firstly, are there any classic exam questions that might pop up around visual impairment?
EY: Oh, let's have a think. So I think, what I'd say in your clinical exam is when, you know, whenever you're commenting on the child's development, whenever you're asked to do a development of any system, it's really important you let the examiner know, you know, it's important to know about the child's vision, hearing and growth. So I know those are the three things I think you should be should be asking for and say, before I approach child, I would like to know if we know any about any differences in their hearing or vision. Because then it helps you put it in context.
So the second thing I'd say that could come up in exams would be interpreting measures of acuity. And also measures of refraction, so you know, a positive prescription of glasses is to correct short sightedness and long sightedness you have a negative. And also acuity measures. You may still get things presented in Snellen's, but we should be moving away from that and using logMAR. So if you can just hold on to that, logMAR zero is normal. LogMAR 1 is like 6/60.
And then the third thing I'd say is you might have to comment on like a strabismus exam. I can imagine that's could quite easily come up. I don't think a child would come into clinic. They'd get a bit tired having to do 10 examinations in a row. But, I think I even had a photograph station where I had to comment on a cover/uncover test and explain what was happening there and whether it was divergent or convergent squint. So that would be useful. And the way to do that is go down to eye clinic and sit in with an optometrist and find out how they do it.
SA: Fantastic. Secondly, are there any useful resources that you would recommend?
EY: Oh yeah, there's loads actually. I, I think anyone who's getting interested in child development anyway trainee level, I would encourage you to become a trainee member of the British Academy of Childhood Disability. It gives you access to loads of online seminars when they come up throughout the year and regional training days and gives you discounts and there's a really good newsletter.
There are some modules within the Disability Matters training package. There are some modules on visual impairment there.
And for those wanting to take more of a deep dive into child development I helped develop a module with McKeith Press. There are a number of modules there on developmental assessment and understanding neurodisability and there is a vision impairment module. Those are paid for resources. So I better say that with that caveat and I'm not trying to advertise them, but they're quite useful.
SA: Fantastic. I will make sure everything is linked in the description below. And finally what would be your three takeaway learning points?
EY: Number one, don't be afraid to get to know children with a sensory impairment. Don't mistrust your skills. If you just watch and observe, and the more children you meet, and the more children you interact with, that's how your confidence will build. And saying that, try and hold on to that advice about forewarning, not directly presenting things into children's hands if they have a visual impairment. And checking in with family if there's any typical way they might begin an interaction. I think those would be really helpful.
Number two, check in with families about what they understand about a child's vision because sometimes things can be written all over the chart and then actually a family might not even know what that means or know what that might mean for what the child can actually see.
And number three, get out there visiting our multidisciplinary team. I think as a trainee you have time. You can go on these days, you can have a taster session. So I'd even try and get out there if it really strongly interests you. Even just have a conversation with a teacher with a visual impairment in your borough when you're on a community placement, find out what they do, find out how they liaise with schools and what they do when they visit children in school. And go down to the eye clinic. see how a child's acuity is measured and reflect on how it's different from an adult.
SA: This has been just unbelievably fascinating. Thank you so much, Eleanor.
EY: Oh, a pleasure.
SA: Thank you for listening to this episode of Master the MRCPCH. We would love to get your feedback on the podcast and any ideas you may have for future episodes. You can find link to the feedback page in the episode description, or email us at
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