CVI Clusters Talk (Slides & Transcript)

To view Part 1 click here.

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Slide 1 In Part 1 we looked at the individual CVIs, and from quite a long list I focused on six.

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Slide 2 These six, and I went through each of them in the session, explaining what they are, and talking a bit about measurements, and measures that can help a child affected by them.

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Slide 3 We left Part 1 explaining that different CVIs have different approaches, and, looking at the same six...

  • Where the detail is not seen clearly, due to reduced visual acuity, make it bigger.
  • Where contrast sensitivity is reduced, increase the contrast.
  • Where there is a lower visual field impairment, or any visual field impairment, use the part of the visual field where the child has the best vision.
  • Where fast moving things are not seen, movement is not being processed typically. This is called dyskinetopsia. Slow things down.
  • Where visual attention is reduced because fewer items can be seen, called simultanagnostic vision, amongst other things, reduce complexity... and
  • Where reaching for things accurately by means of vision is impaired, called optic ataxia, keep things in the same place to use memory based reach.

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Slide 4 It took me an age to learn all the names of the CVIs...I couldn't remember them... I couldn't pronounce them... and I couldn't even begin to spell them!

These six CVIs are important because they are commonly found in children, and many children are affected by several of them at the same time. They can of course be affected by other CVIs.

It can become an overwhelming amount to learn, which is why I have just stuck with these six to begin with.

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Slide 5 Some of the commonly found combinations of CVIs in a child we have called CVI Clusters, that's just our name for them.

As I wrote this talk, I got a bit stuck here, because what I need to explain is

  • multiple quite complex brain processes
  • not working typically
  • also, processing inconsistently, making the behaviours inconsistent,
  • at the same time
  • in the same child
  • allowing for the fact that every child is different,

something that has taken me the best part of five years to understand, and I have thirty minutes!

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Slide 6 This is what I came up with, simple icons for each cerebral visual impairment, so here, for reduced visual acuity, we have a magnifying glass with the letter A for acuity in the centre.

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Slide 7 In real life colours and contrast are combined together. This diagram is called a colour solid. It shows how the primary colours usually have a bit of black or white added, with red becoming brown or pink when this happens. So reduced ability to tell different shades of grey from each other, or reduced contrast sensitivity, makes it difficult to see different shades of brown or pink, or light and dark blues one from another.

Hopefully seeing this image makes it easy to connect with the issues around how clearly shades and tones of colours are seen.

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Slide 8 For dyskinetopsia I have someone running because it is all about how we see things that are moving, especially when moving fast.

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Slide 9 For optic ataxia I have a hand, because it is about reaching for things accurately.

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Slide 10 This grey oval is meant to represent the visual field area, and the white inner oval, a window of vision, because that is how simultanagnostic vision has been repeatedly described to us. We explained a bit about this in Part 1 with videos, and will add to those explanations today.

The window of attention is different to the window of the visual field. The window of the visual field is permanent and does not change, while the window of visual attention varies. When there is too much to attend to, the window of attention can narrow, but it widens when there is no clutter or distraction. This process is magnified greatly in many people with CVI.

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Slide 11 Finally, this is our visual field, I thought it would be easier to remember if I made it an actual field! I have not added lower visual field impairments, but will as we go through.

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Slide 12 Here we have all the icons, each with its cerebral visual impairment. Next to them, I have made a simple column just with what is visually impaired, because that is the bit we need to know, in relation to each child - which areas of vision are not processing typically?

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Slide 13 So this person running represents a visual impairment of how moving things are processed, meaning fast things are not seen so well.

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Slide 14 And the hand represents a visual impairment when it comes to reaching for things accurately and so on with the other CVIs.

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Slide 15 So for explaining the clusters, hopefully the icons and simpler terms will make it easier to put everything together. This is the first time I have explained it like this, I am really simplifying things but all the terms were more clearly explained in Part 1 and hopefully when I move onto the clusters it will make sense.

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Slide 16 Before I start explaining some of the clusters, we need to remember that every child with CVI is different. And...which CVIs they are affected by is just one part of what you need to know about them - they may have other conditions, different strengths and likes and abilities based on multiple other factors, particularly their life's journey so far.

The clusters are common combinations we think may be helpful, because if you see one you can check for evidence the others. Ideally each child would have a comprehensive diagnostic assessment, where the different CVIs affecting the child's vision are determined.

Where did we get these clusters from? Experts who have been diagnosing for years, although there is research featuring these combinations. I am presenting a simplified version today, but everything can be evidenced.

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Slide 17 So this is our first cluster. If you look at the visual field, you will see the bottom slither has been coloured black, this is because one of the CVIs in this cluster is a lower visual field impairment.

We know from Part 1 that lower visual field impairments vary from person to person, and can mean from a loss of clarity in the lowermost part of the visual field, to no vision at all for the entire bottom half.

Slide 18 (Video)Video Link:

Slide 18 (video) So, that bottom slither, is pretty important for walking, and not tripping.

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Slide 19 In cluster 1, the lower visual field impairment is typically mild, so just affecting that lowest slither of the visual field. (Visual field testing equipment does not test so low down, so may not detect this slither.)

When walking, the child might not be aware of it, but the tips of their toes as they move forward are in the very bottom of their visual what issues might there be if the bottom slither was missing?

They might trip over things that are very low down.

They might not be so good at games where the ball is low down, like hockey or soccer.

Stepping onto a downwards escalator and going downstairs, especially if there is no rail may be difficult and avoided...because if you can't see where your feet are going, you might fall...a person with a lower visual field impairment may well have had previous experience of falling down stairs and this could be the reason for their anxiety about stairs.

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Slide 20 This is our oval icon with a window of vision for simultanagnostic vision.

How simultanagnostic vision has been described to us is like a window of vision within the visual field.

At its most severe level it has been described like seeing life through a straw, and with stress can deteriorate into a state of functional blindness...but for this CVI Cluster it is usually mild, so the window of vision is still pretty big, not quite as big as typical, but they would probably be unaware their vision was different to anyone else's, and this almost certainly would not be picked up in a standard sight test.

Reduced visual attention due to simultanagnostic vision is not going to be a perfect oval - these diagrams are just illustrative. The window of vision will depend on many things.

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Slide 21 If the brain is working typically, the whole visual field should be mapped. So this image illustrates a whole visual field, so there is no visual field impairment here.

It is the case for all of us that we see most clearly in the centre of our visual field, and reach for things with most accuracy in the centre of our visual field - but the whole visual field is mapped.

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Slide 22 With this cluster, not all of the visual field is mapped - this mapping process is important - the picture has been created, but not all of the picture has been mapped. I think that is one of the most complicated parts of CVI to understand. We have dedicated Level 9 on our series of Lessons just to explaining that mapping process - so in this image, the area now covered with the grey represents the area that has not been mapped...

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Slide 23 Because there is process...visual attention follows on from the mapping process, so if an area of the visual field is not mapped, then there is nothing to add attention to. Where visual attention is absent, you can't see. No map, no attention, then of course, there is nothing to take to your libraries of memories to recognise.

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Slide 24 Compared to typical vision though, it still seems like there is a fair amount to see, although from repeated accounts, visual attention is likely to be dynamic. Somewhere open and clear, vision may be almost typical, but

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Slide 25 When somewhere busy, or a bit tired, or stressed, then the area of visual attention may reduce, meaning...

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Slide 26 The same person can see better when somewhere quiet, familiar and when they are feeling well, and have reduced vision when tired or somewhere busy.

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Slide 27 So someone affected may seem less attentive when tired or somewhere busy.

They may need breaks... this mapping process is going on all the time in all of us, and it can be exhausting if not working typically, and that is going to make staying focused in class difficult, so a child might find it hard to keep up, and may start to fall behind.

Recognising people puts a great demand on our brain, and this could be tricky for some with this type of vision, as can be recognising facial expressions, and this can lead to social difficulties.

The child may have some mild recognition issues, which would be difficult to separate from learning difficulties.

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Slide 28 As I was writing this, I realised I used the expression 'this type of vision'.

CVI is technically seen and measured as an impairment...a deviation from what is considered normal...less of something or low something.

Maybe it is the parent in me, but I look at my son with CVI and marvel at the things he can do.

For me, I think the clusters helped me understand CVI as a 'type of vision', with a focus on what a child can do, not what they can't do.

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Slide 29 Back to cluster 1... reaching for things accurately is difficult to illustrate so I am going to explain, but first...

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Slide 30 For our images, I am just going to put the hand on the field, to show this is included in this cluster, I've just changed it to white to make it clearer.

And here is our first cluster...

Showing the lower visual field impairment, slightly reduced visual attention and with the symbol of the hand, inaccurate visual guidance of reach.

Thinking of mild difficulties reaching for things accurately, this might make a person sometimes a bit clumsy...but what else?

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Slide 31 Think about putting your pen on a piece of paper to write...

The picture your pen, held in your hand, is guided through, is created in your mind.

Because your mind has placed the paper accurately, where you are aiming for...and ....that's your visual map doing that...your pen goes to exactly the point you want it to.

But what if it is a little bit 'out'? So when you put your pen on the paper it doesn't quite go where you expect it to...because where the paper is in the real world, and where your mind has placed it, are slightly different...even just a millimetre or two...what might your writing be like?

Maybe a bit like this?

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Slide 32 Anything requiring fine levels of accuracy may be difficult for the child, who may...

  • seem a bit clumsy
  • struggle with handwriting
  • have difficulties with activities needing fine accuracy skills e.g. needlework

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Slide 33 So bringing everything together, we have a mini-profile of some of the challenges a child with CVI Cluster 1 may face, I know this is a lot of info on one slide - it is just all three put together. So what does this child need for support?

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Slide 34 The purpose of explaining the clusters in terms of the individual CVIs is so that you can decide what support is necessary, because every child with CVI is different, including their home and school set up.

If you know they don't like stairs, and particularly between classes when it is really busy with lots of other children and noise, then make a plan, which might be going first or last or staying to the right where there is a rail - do what works for the child.

The child with CVI is the most important resource on the child with CVI.

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Slide 35 You may have test or assessment results, brain scans, different strategies and suggestions that may have worked with different children.

This makes up a cvi toolbox, and a good tool kit is a great resource, but only in the hands of someone who will confidently put the child first. I have put a link to a blog from US CVI educator Amanda Lueck about this, and as far as CVI toolboxes go, she must have one of the best, but writes, for both parents and educators...

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  • It is so important for parents to trust what they have learned from their children and to communicate this to professionals.
  • I have found that it is important to wipe the slate of my preconceptions utterly clean, although this is not so easy to do.
  • I have learned to watch as each child teaches me and others how he or she experiences the world.
  • Each child is a universe. And each universe has its own rules, checks, and balances.

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Slide 37 I love this quote...each child has their own rules, checks and balances...

Optimised support is targeted, to the individual child.

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Slide 38 Here are just a few suggestions of what is an enormous list...

  • Check tiredness, plan breaks
  • Encourage friends and family to use words to express how they feel rather than rely on a fleeting facial expression.
  • With handwriting, joined up writing can help, but also learning to touch type and thick wide lined paper.
  • Encourage talking, learn where life is difficult

Talk, use words!

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Slide 39 I have learned from so many accounts from parents that when a child finds something difficult, whether it is school work, making friends, being good at sport...they blame themselves...

"it must be me...something isn't working...something is missing....I am the problem..."

That is talk to children, open up the conversation about difficulties to find out the cause, and then look at what you can do to help.

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Slide 40 I talked about the 'CVI Project' in my last talk, which was looking at how many children in mainstream schools may have CVI. They have now published their findings...

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Slide 41 Across several mainstream primary schools, so that's age 5-11 and the average age was 8, they found at least 3.4% of the children had CVI related visual difficulties. With my references I've included a link to our introduction to the paper explaining the figures and issues they raise.

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Slide 42 One of the issues is that it is looking increasingly likely than in addition to being the biggest cause of childhood visual impairment in economically developed countries, CVI might also be one of the biggest causes of learning difficulties in children. Of the children found with CVI related difficulties... 80% were struggling in school on some level.

I've included in my links another study in a mainstream school, it was only small, but shows compelling links between autism and CVI.

The CVI Project findings mean CVI is likely to be more than three times more common than autism, in mainstream schools.

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Slide 43 Our next cluster, CVI Cluster 2, looks a lot like cluster 1 with an addition... the difficulty of clearly seeing things that move clearly, particularly if moving fast. Everything else is as CVI Cluster 1, but a little more severe.

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Slide 44 The window of vision is smaller and the lower visual field impairment is likely to be slightly more severe. It might still seem like there is still a lot of vision available.

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Slide 45 But compared to typical vision, we see that there is a considerable amount of vision loss across the field of vision.

These diagrams are just illustrative, to explain the point.

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Slide 46 We have the added difficulty of how things that are moving are seen, what might that be like for a child with CVI?

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Slide 47 Have you ever stood on a train platform, when a fast train is passing through the station and not stopping, and you have to stand back behind a it passes there's a sort of thud followed by lines where the clarity of the moving train is lost.

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Slide 48 Imagine that, but not a fast approaching train, instead, the same experience but from a car driving not very fast in a neighbourhood, or even a cyclist... things everyone else can see clearly, suddenly coming into view like out of nowhere, but can't be seen clearly, and just as quickly disappearing. We can't know for sure what it's like, but certainly from my son's reaction to moving things, this is how I imagine it may be like.

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Slide 49 So let's look at the lower visual field impairment, when it's affected a bit more severely.

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  • One added issue here may be that things are repeatedly tripped over and not learnt.
  • The same difficulties with sports with a low ball (e.g. soccer, hockey).
  • Going down stairs or escalators might not just be avoided but can be a cause of anxiety or stress.
  • Several children we know with this level of lower visual field impairment choose to watch television on the floor looking up to the screen.

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Slide 51 If we imagine this is the full television screen as seen with typical vision.

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Slide 52 With a lower visual field impairment, if the child is positioned with the centre of the television screen at eye level, as with the image on the left, they may not be able to see the bottom half of the screen.

If they move their position down, maybe sit on the floor and look up, or kneel, they are also moving down their lower visual field impairment, and more of the television screen is available to see, so the programme will make more sense and be more enjoyable.

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Slide 53 And going down a slide head first - why?

Slides are fun, we all know that, but probably a lot less scary if you can see where you are going, which you can when going down head first, if you have a lower visual field impairment.

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  • It is a very common CVI.
  • It is relatively easy to spot and measure, if you know what you are looking for, think back to the demonstration, and where you can see the tip of your toe - not all children can follow instruction to do this exercise, but clues like the slide, watching tv and regularly tripping over things low down or missing things are very good indicators.
  • It is quite consistent, whereas many other CVIs are very dynamic.
  • It is a good indicator of specific other CVIs to look for.

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Slide 55 Let us look at that window of vision with Cluster 2...

  • As with cluster 1, the child may be less attentive when tired or somewhere busy.
  • Need breaks, can quickly become overwhelmed, stressed and confused.
  • Struggles socially, possibly leading to behavioural challenges.
  • Can severely affect all aspects of learning.
  • Loses things and can't find things.
  • May be a little obsessive about things not being moved.

This list is starting to look a lot like autism.

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Slide 56 Let's look at reaching for cluster 2, again as cluster 1 but more severe.

  • May seem very clumsy.
  • May struggle with writing / copying / drawing.
  • Difficulties with activities needing accuracy of motor skills e.g. catching a ball, tying laces.
  • May line things up.

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Slide 57 Why line things up? If reaching for things and searching for things are difficult, by placing toys in a line, or in a remembered order, they are easier to find and see, and if they easier to see they are easier to reach for and therefore easier to play with.

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Slide 58 Looming was first described to me by a mother who described her son in the supermarket.

He loved holding on to the shopping trolley, but would regularly brace himself as if something was about to hit him, even though there was nothing that she could see.

His brain had not mapped his surroundings accurately, and in the same way he could not reach for things accurately, he also could not tell how far away things were. This was made more difficult while moving and by a cluttered environment, and he kept bracing himself for impact.

The bin in this picture caused a person with CVI to scream, from the first-hand account it "suddenly appeared in front of me and terrified me. I screamed, jumped and almost ran away".

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Slide 59 When it comes to using a pen or pencil, it must be so frustratingly difficult for many children with more marked optic ataxia.

For the same reasons I explained with handwriting, but so much harder.

One thing to consider is breaking every task down to learning just one new thing at a time.

If a child is learning a letter, maybe the letter S, let them copy it with their finger, maybe in a tray of sand...or a lovely quiet open beach if you are lucky enough to be near one.

Let them build familiarity with the letter, what it looks like, how it is formed - you are creating a memory, and as they re-create it over and over, that visual memory becomes stronger and a form of haptic memory, connecting what is seen, felt and known.

Then, when the child tries to form the letter S with a crayon or pencil, they already have that letter, what it looks like and the movements needed to make it in their mind, and from that, the incredibly difficult challenge of copying it onto a piece of paper can start.

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Slide 60 I explained this last time I know, but can't stress it enough, especially where learning is difficult for a child with CVI.

One step at a time, only one new thing at a time, starting with what the child already knows, in a way the child can learn, which may be different to how other children learn, at their pace.

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Slide 61 Continuing with our profile...

  • Inconsistent vision, things are sometimes seen clearly, sometimes they're unclear, sometimes they're not seen at all.
  • Easily confused as things appear and disappear.
  • Sometimes startled or frightened.
  • Dislikes places with lots of movement.
  • Feels safe in car.

The reason cars, and also wheelchairs may be preferred is because there might be a learnt understanding that they are protected, like a protective shield, and they can switch-off, relax and enjoy being out and about, rather than frightened and startled.

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Slide 62 Bringing everything together from cluster 2, we have another profile - this is very general, and what you need to do is make it specific to the child with CVI you support.

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Slide 63 And from their unique profile, create a programme of targeted support...for that child, which of course needs to be organic and evolve with the child, because if you get it right, then that child is going to learn and develop, so their programme of support will need to be reviewed and updated as they progress.

As might be expected, for those whose CVIs are both more severe and more in number, learning and other areas of development will be more severely affected. This is not the case for all, we know of both very severe CVI in very able children, and very mild CVI in profoundly learning disabled children, but broadly speaking, as the CVIs become more severe, there are greater support needs, and you may find children with communication difficulties in this group.

Supporting a child without language is a particular challenge, I have included a link about understanding the needs of non-verbal children with CVI from our Pick & Mix sections.

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Slide 64 So, this is our second cluster.

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Slide 65 And here we have the first and second cluster next to each other.

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Slide 66 The third cluster is as cluster 2, but everything is more severe with the added elements of reduced visual acuity and reduced contrast sensitivity.

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Slide 67 The lower visual field impairment is more severe, maybe covering the whole of the bottom half of the visual field, and the window of vision even smaller.

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Slide 68 This is the cluster I went through in Part 1 explaining my son's CVIs, and we edited this photo of me, simulating his multiple CVIs and ended up with the image on the right as his vision, compared to typical vision.

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Slide 69 We started with clear images, and using the programme sight-sim, edited them to show increasingly severe levels of combined reduced visual acuity and contrast sensitivity.

I am not going to go through this cluster in detail again because I have already covered it, if you didn't manage to see Part 1 it is available on line.

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Slide 70 Just look at what has happened. From typical vision, there is a combination of the lower visual field impairment becoming more severe and the window of vision reducing, so rather than thinking of very fixed clusters 1 2 or 3, think of this as one of the many CVI spectrums, a common one found in children.

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Slide 71 As a greater area of the brain is affected, everything is more severe and more CVIs are added, because the areas of the brain where they are processed are affected.

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Slide 72 With cluster 1, most of the processing issues come from the back of the parietal lobes, with cluster 2, that extends to a part of the temporal lobes, and with cluster 3 extends further to the occipital lobes.

With that, I am going to thank you for your time, I really hope it has made sense... thank you.

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