Cortical Vision Impairment: Assessment and Intervention

Ellen Mazel discusses how the vision is processed in a child with cortical vision impairment (CVI) and the importance of early intervention.

Ellen Mazel discusses how the vision is processed in a child with cortical vision impairment (CVI), how the child understands the visual part of their world, and the importance of early intervention. She also offers strategies for assessment and intervention.

Read full transcript »

Read Q & A with Ellen Mazel »

Presented by Ellen Cadigan Mazel, M.Ed.

Length of time to complete: approximately 30 minutes

Attached File(s)

Download the Audio Version 


  1. Introduction
  2. Evolution of Intervention and Assessment
  3. Assessment and Strategies for CVI Characteristics
  4. The Benefit of Early Intervention

CHAPTER 1: Introduction

MAZEL: CVI is a brain-based visual impairment — it’s also called cerebral visual impairment, you’ll hear it called both — and it’s the processing of the visual information that is not happening for children.

Cortical Vision Impairment with Ellen Mazel.And vision is processed in, like, 30 different parts of your brain, and some do movement, some do color, some do form, and certain areas are not working for children. So we’re really looking at how the vision is process, how the child understands the visual parts of the world.

CVI is really the leading cause of visual impairment in the United States and I believe in western Europe as well. Just with the improved medical science, the children are born earlier and survive, sometimes at 24 weeks, and that can also bring some problems with brain bleeding or problems with the eye.

NARRATOR: In a photograph, an infant delivered at 26 weeks is shown in an incubator. The infant is attached to a ventilator.

MAZEL: 90% of what a child knows comes through the information that they’re getting through their eyes, so extremely important for all levels of learning.


CHAPTER 2: Evolution of Intervention and Assessment

MAZEL: I’ve been working for 30 years, and years ago, we had children with what they called cortically blind on our caseload, and we would go in with our bag of tricks that we had for a child with an ocular problem, and we’d try them, and nothing happened, it wasn’t working. I think we blamed the child rather than saying, “We don’t know what we’re talking about.” We blamed the child. And things have changed now: the information is new, the information is out there, and I think it’s very exciting because we’re seeing real changes in children.

We’re really seeing improvement. We’re expecting improvement. I was lucky enough to go to a conference. Christine Roman, who is one of the largest researchers in the field, gave a conference here at Perkins, and it was really professionally life-changing.

NARRATOR: The cover of one of Christine Roman-Lantzy’s books, Cortical Visual Impairment: An Approach to Assessment and Intervention, is shown. The cover illustration shows a young boy in a sweater leaning over a light box and manipulating colored blocks.

An image of a brain scan shows a lateral section of the brain with activity in the visual cortex highlighted. MAZEL: She talked about the characteristics that she’s looking up. She talked about her assessment tool, she’s talked about some strategies to work with children. I took that very little bit of information and went back to the kids that I was working with and I could see results, and that was very exciting. So it really started me to say, you know, “Well, what else can I know? What else is it about the brain that’s interesting?” And we find this is the decade of the brain. There’s just so much information everywhere, and with the Web, of course, we can really find this information and apply it to the work that we’re doing.

I really think it was the ability to image the brain in real time and research about the brain function — typical brain function — and therefore, you know, then you can find out about brains that are not functioning in the same way, you can really get the information that they needed in real time to take a look at where this information, where’s the color being processed, where are forms being processed in the brain, and really figure out what could be going on, what could be going wrong.

NARRATOR: An image of a brain scan shows a lateral section of the brain. Activity in the visual cortex causes the area to be highlighted in yellow.

MAZEL: I think that parents have really stepped up and said something has to be done, they’re noticing that their children are not responding to their faces, they’re not tracking items as babies when parents know they should be. And parents take their children to pediatricians and ophthalmologists and get bounced between the ophthalmologists and neurologists in an effort to get an answer to this question: “Why isn’t my child seeing?” And then seeing characteristics that they say, “Sometimes my child sees this, sometimes they’re seeing red,” or “When I move across the room, they seem to follow me, but they don’t follow other things.” So there’s little hints that a parent has and terrific information for us as teachers that help us understand how that child’s processing information.


CHAPTER 3: Assessment and Strategies for CVI Characteristics

MAZEL: We start with color because it’s probably the most important feature about an object. Parents have been telling us for years, “My child likes Elmo, my child likes Big Bird.” The red and the yellows are two colors that are very, very highlighting to everyone’s brain. And kids with cortical vision impairment, it tends to be the colors that they’ll look at. So that would be one area where we’d look at first, would be color. If we know a child will look at a red, then we want to infuse that color into the things we want the child to look at.

NARRATOR: An image of a child’s bottle ringed by a bright red fabric is shown.

MAZEL: Wrap the red on the baby bottle, underline the red words in the storybooks, things like that that can really highlight the salient features we want children to look at.

A child's bottle ringed by a bright red fabric. NARRATOR: A graphic of the word “movement” appears on the screen.

MAZEL: And then we would look at movement, for instance. And movement is a primitive visual skill. We all see movement more than we see stable things as an early visual behavior. And children with cortical vision impairment, the movement of an object will draw visual attention much more than a stable object, and, in fact, some children with cortical visual impairment cannot see things if they’re stable.

NARRATOR: A video clip of a lava lamp is shown. The slow motion of the material in the lamp and the internal illumination provide an attractive visual target.

MAZEL: So if I’m going to show a child something, I’ve got to create some movement in that material in order to draw their visual attention.

NARRATOR: A graphic of the word “latency” appears on the screen.

MAZEL: Another characteristic that we look at that’s very important is latency. That’s the length of time it takes for a child to realize an object is there and then turn to look at it. And unfortunately, the world is a very fast-paced place and things are not in a child’s view as long as they need it to be.

NARRATOR: A young boy sits in a wheelchair facing the camera. To the left of the screen, a bright green ball is shaken. The boy’s eyes track slowly towards the object, and he turns his head and smiles.

MAZEL:So a strategy for a child with latency problems is to leave the materials in a location for a long enough time for them to visually attend to it and then turn to visually examine it. So that would be a strategy that we would mention for classroom teachers.

NARRATOR: A graphic of the word “novelty” is shown.

MAZEL: Another area we talk about in cortical visual impairment is novelty. Children with cortical visual impairment tend to see things they’re familiar with, things that have been in their environment for a long time. So if I meet a family with a baby with cortical visual impairment, I’ll typically ask to see the crib. I go in, I want to see is that green bear sitting in the corner of that crib, has that always been there? And what I might find is that kelly green bear is a color that that child can process because it’s just been in their environment for a long time and they’re able to see that.

NARRATOR: We see a bright green teddy bear against a dark background.

MAZEL: So in instruction, we want to, if we’re going to be teaching a new skill, we’re going to be wanting to use very familiar materials with that child because then they’ll have a better chance of learning the skill that you’re trying to teach. So that would be another strategy for that characteristic.

NARRATOR: A graphic of the word “distance” appears on the screen.

MAZEL: Distance is another characteristic that we look at. How far away can a child process the information? And typically, children with cortical visual impairment will see things that at near, not because there’s anything wrong with their eyes, but because if I hold something near, I have less of this to look at. The further away something is, the more I have to look at. So we really tried to think about what distance can a child process the information.

NARRATOR: A graphic of the word “complexity” is shown.

MAZEL: I think one of the biggest areas for classrooms and for families is complexity. That characteristic is extremely important for cortical visual impairment. And complexity has really three areas.

A laminated card with the words snack foods and illustrations of a pretzel, cookie, and peanut. We have visual complexity, which is the amount of things that you have to look at, the background of busyness that there is in the world that a child needs to process one item from another. So a strategy to try and get a child to look at an item, if background busyness is a problem, is to use solid color backgrounds, contrasting colors to a background, one object at a time rather than many things to look at, to really reduce the visual complexity of the environment.

NARRATOR: A photograph shows a laminated card with the words “snack foods” and illustrations of a pretzel, cookie, and peanut. The card is trimmed with shiny red foil and presented on a dark black background.

MAZEL: Auditory complexity is another area within the complexity characteristic, and that’s what level of sound can a child process at the same time they’re looking. And typically what we’ll get is as soon as the noise level gets up, the looking stops. The child cannot look any more. And parents will often report they cannot take their children to any malls or any busy places.

The children just really can’t handle the noise and the visual processing. And then the third area within complexity is positional complexity. And that’s really making sure that the child’s body is very stable, feet down on the floor, solid seating, so that they’re not trying to position themselves in space while they’re trying to look. And so we look at how solid or how positionally complex can we get that child to still maintain the visual contact with items.

NARRATOR: Again, we see the video with the boy in the wheelchair, noting this time that his shoulders are harnessed to provide positional stability. A graphic of the words “visual reflexes” is shown.

MAZEL: We have visual reflexes. If I touched you in the middle of your eyes, between your eyes, you’re going to blink immediately. If I quickly come up with my hand in front of your face, you’re going to blink immediately. Children with cortical visual impairment will have either absent reflexes or it can be delayed. So that’s not really an area that we provide instruction around because it’s a reflex, but it’s definitely an area that will give us a little bit of a clue as to how fast processing is happening.

NARRATOR: A graphic of the words “visual fields” appears on the screen.

MAZEL: Visual fields is another area that we think about in cortical visual impairment. Typically, children with cortical visual impairment see better in their periphery. And again, I think that developed evolutionally…seeing off in the sides, seeing movements in the side may have protected us in the wild so that we can see danger and get away from it. And that seems to be very intact in children. So positioning of materials slightly off center to allow a child to visually locate it and then turn on their own to look at it is an important piece.

A boy with CVI tracks a ball. NARRATOR: In a series of two photographs, a young boy is sitting, with his neck supported, while a purple ball inside a bright yellow frame is introduced into his field of vision. In the second photo, the ball is moved to the boy’s right visual field and his eyes track to the ball.

MAZEL: We might also see children having either left field or right field or upper field or lower field problems, and this is where I like to get the neurology reports, because if I see in a neurology report that maybe there’s damage on the left side of the brain, I might be looking for less visual abilities on the right side, so that can give us a lot of information. And again, instructionally, we’re really wanting to put materials where the child is going to see them best.

NARRATOR: A graphic with the words “lights & lighting” appears on the screen.

MAZEL: You see children with cortical visual impairment will often have their heads tipped up and they’re looking at the lights above or they’re looking towards windows. And that’s not really very functional, to just be able to look at light. So, educationally, we want to make sure that that light is placed behind the children so that they’re paying attention to some of the more important visual targets that we’re asking them to look at.

NARRATOR: From the cover of Christine Roman-Lantzy’s book, we see the photograph of the young boy leaning over a light box and manipulating color blocks.

MAZEL: So it can be something that we want to avoid, but at the same time, we might instructionally use light to draw a child’s visual attentions. And then the visual motor responses. That is the ability to see something and then have visually directed reach — you’re reaching and you’re looking at the same time. Or you’re playing with an item while you’re looking at it. And typically, children with cortical visual impairment cannot look and use their motor skills at the same time. So you might get this kind of behavior where they’ll see something and then when they reach for it, they have to turn away. They cannot do both things at once.

NARRATOR: A photograph of a young child’s hand and wrist is shown. A bright red hand splint covers much of the hand. The brightly-colored splint might draw visual attention by highlighting with red.

MAZEL: This is an area for us to assess because, of course, maintaining your vision on what you’re playing with or what you’re interacting with is how you’re going to learn about that particular item.


CHAPTER 4: The Benefit of Early Intervention

MAZEL: I’ve never seen a child of any ability not make improvements, and I think that’s a very different way to look at our business. We know that brains are plastic. They’re plastic all the way through life, we’re all happy to know, but particularly in the early stages of life, and between the ages of one and five, it’s extremely plastic. So we want this time to be used very, very carefully, to put these strategies in place so that we can make those improvements. And I think if there’s anything anybody should walk away from, hearing about cortical vision impairment, it’s that we are expecting improvement. We are expecting to see that visual behavior improve, and typically, when we see improvements in one area, like color or movement, we’ll see those improvements in all areas.

NARRATOR: In a video clip, we see a toddler in pink glasses spinning a toy that is made up of a ring of brightly-colored bells.

Toddler playing with a toy made up of a ring of brightly-colored bells.MAZEL: I think that a large part of my job, at this point, just because I’m out in the community, working with early-intervention teams and working with doctors on teams, is to really get people to understand cortical vision impairment and to start to work more collaboratively. The ophthalmologists typically will think about the health of the eye from the optic nerve forward, you know, what does that eye look like. And with children with cortical vision impairment, often the eye looks perfect.

The family goes in and the eye doctor says, “Everything’s fine,” but yet that child’s not looking at anything, so everything isn’t fine. So they might get sent to a neurologist who will take a look at the brain, but again, not the functioning vision part. So how can we get these two people to work together a little bit. And then educate early intervention providers, because if the child’s not looking, there’s probably other things going on, other types of needs that would refer them to early intervention. So you would really want to be educating the early intervention providers about what cortical vision impairment looks like and bring in a teacher of the visually impaired to really help sort through what visual piece this might be, because if we can take that visual piece out and see what’s left, that can give us a lot of information.

Again, 90% of what you’re learning is through your eyes, so if you’re not using your eyes, cognitively, you’re going to be behind, motor, you’re probably going to be behind. It affects every part of your development. If I were a parent, I would be asking — if my child wasn’t using their vision — for a teacher of the visually impaired to be on your team. And again, I think it’s everybody’s responsibility to really be educating themselves.

Parents certainly are out there, surfing the Web for every bit of information they can possibly find about their children, and I just hope that professionals would be lifelong learners, that this is a brand new thing, and even if you’ve been in the field for 20 years, you should be out there learning this brand new thing and putting it in place, and these are children that are going to be on your caseload and the need for intervention, because we know there will be improvement, is essential.

Cortical Vision Impairment with Ellen Mazel.

young man in a classroom learning to read braille

Transition assessments: an overview

an open book, displaying "CVI" on its pages

Literacy and CVI

graphic of a finger pressing a CVI symbol

Augmentative and Alternative Communication (AAC) and Cortical/Cerebral Visual Impairment (CVI)