First, yes, so just a little bit about where I'm coming from. So I work for an organization called undivided and we help parents who have kids with disabilities. So we write a lot of articles for the website that are free for parents to go read and get you know advice from experts and insights. So I'm a writer and editor for and divided right now. We're doing a whole series on, like low incidence disabilities. So we're doing like, low vision, deaf and hard of hearing. This one is on CVI, so they connected me to you. So, yeah, can you tell me a little about yourself and your you know? I mean, obviously you work with kids with CVI, so just a little bit about you. Yeah,
absolutely. I'm a pediatric neuro ophthalmologist here at Children's Hospital Los Angeles, and I see a lot of kids with CVI in my clinic. It's probably one of the most common things that we see in our clinic, which makes sense, because CVI is considered the leading cause of visual impairment in kids in the US, and I also do a lot of research in kids with visual impairment. So right now, lab is looking at different ways to sort of assess the visual function in kids with CVI and quantify it so that we can, in the future, run clinical trials of interventions for CVI right now, there's not really, like, an evidence based medical treatment for CVI, so we hope that with our research, we'll be able to identify one.
Okay, great. Yeah, that was me, my one of my questions about how common it is compared to other visual impairments, but yeah, it is. You said it's one of the most it is the most common.
Yeah. I mean, I guess some sources say it's the most common, and some say it is a leading cause. Other common causes, of course, are like inherited retinal disorders or ROP or optic nerve hypoplasia, but it's certainly like one of the leading causes,
and who, oh, Marlin entered.
Hi, Marlin. Hi, sorry, I'm sorry I'm late. Hi, Dr, Chang, thanks for joining Adeline. I'll just be quiet. If you need anything for me, let me know, and I'll just mute myself out. Thanks. Thank
you. Okay, so, yeah, so who, typically, I mean, what? Who is evaluated for CVI? Like, what? Like do parents have to look for certain signs and symptoms? Like, what brings a typical child to to you?
I would say most of the kids could who come to my clinic are referred from pediatric neurology. Some are referred from pediatricians. But in order to have CVI, they need to have some kind of underlying neurologic diagnosis that affects the visual pathways in the brain. So most commonly, it's like prematurity of periventricular leukomalacia, or they could have like hydrocephalus or hypoxic ischemic encephalopathy or head trauma. So those are all risk factors or also intractable seizures, especially those that have like epileptic encephalo encephalopathy, so their brain development is altered by their seizures. So usually these patients are identified by pedia technology. But patients at risk are also sent by pediatricians as well.
And is it usually notice that birth, or does it, you know, happen over time that parents will notice, or the or the pediatrician will notice, like, is there a typical age that is? It's diagnosed.
So I guess most cases of CV that we see are in patients who have had a risk factor for CVI as a infant or even in utero. But the age of diagnosis really varies. I'm hoping that it's getting younger as people are get becoming more aware of CVI. So, you know, I guess most commonly I see kids are like, around age two or three with CVI, but there are kids who are missed until they're older, especially kids who are have like, what we call higher functioning CVI, where, like, they have pretty good visual acuity so they can meet their visual demands when they're younger, but as they get older, they have problems with like visual processing, and it becomes more apparent as the visual demands increase. So we do in our definition of CVI said that say that they must have had an insult to the developing brain. So this is a disorder that start in childhood, or at least, like the risk factors start in childhood.
And is there? Do you see any kind of like misdiagnosis when you know, if it's missed, like, are they misdiagnosed with something else?
It is frequently missed because the kids, especially those who have, like, more profound, sort of cognitive. Delays, they can't really tell us when they have problems with their vision, and vision is not like the first thing that their other doctors are thinking of, because they have such profound other like developmental delays. So I think that's why it can sometimes be unrecognized. Sometimes people get CVI confused with dyslexia, and dyslexia is not the same as CVI. Dyslexia is a disorder of language and language processing, and really it's more related to how well you can sort of put together sounds like phonology. So in that way, it's a little bit more related to like auditory throughout the visual processing. So people who have CVI can read, like, for example, Braille, well, well, if they have a cognitive capacity, so it's, it's not a disorder of language or reading. It's a disorder, truly, of vision.
Yeah. So for the kids who do have, let's say, co occurring, other disability, you know, autism or CP or Down syndrome, and they also have this. How is it assessed, like to find that they have CVI? Do they have to have some kind of a brain? I don't know what the process would be, but like a brain scan or something, or Yeah, how is it determined
so you don't necessarily have to have an abnormal brain? MRI, previously, I guess people thought that you had to have have the MIB abnormal before you could diagnose CVI. But we now know that there are some conditions, especially like genetic conditions or certain seizure disorders, where the brain is structurally normal but it's still functionally abnormal, and they could still have CVI in terms of diagnosis in sort of developmentally to relate children, it's very challenging. If they have, like, severe CVI, where they have decreased visual acuity, they're like, you know, close to being blind, or like severely visual paired, then it's much easier for us to diagnose CVI based on their visual behaviors. But if they have, you know, pretty good visual acuity, but they have problems with like, visual processing, visual attention, then it becomes very hard for us to detect in these kids who are non verbal or who don't communicate well, and that's one of the things that we're studying with our research. So we're using eye tracking to see where they look when they look at various images on the computer monitor to help us better understand their differences in visual tension and perhaps have an objective way to diagnose CVI in these kids who are more developmentally delayed.
So with the diagnosis, will a regular checkup with their, you know, ophthalmologist pick it up, or, you know, an optometrist, like how, yeah, who would those doctors be able to pick it up? Or would they have to be, you know, going one step further to someone you know, like you. I
hope that pediatric ophthalmologists and optometrists are able to diagnose CVI. Now, last year, we published a working definition of CVI with this group through the NIH and this delineates, you know, the characteristics of CVI, to help increase awareness about CVI, but also help people who don't have like specialized training providers like pediatric ophthalmologist and optometrist to be able to feel comfortable making the diagnosis. But you know, there may be some subtle cases where they might not feel comfortable and they might have to see a sub specialist,
and then, like, with the testing to test if they have CVI, like, how are you testing to tell the difference between, like, it's not an eye problem, it's like, in the brain, or is there some, like, some difference in the testing process?
Yeah. So, I mean, we have to get a measure of, like, how well they're using their vision. So there are some things we can do in the eye clinic, like seeing like their visual acuity, or what the small see they can see, or like their contrast sensitivity and sort of their visual function. And then we also could do like functional vision assessments to see like how they're using their vision to do activities in daily life. And then we have to put that together with the eye exam, because if they have like, an eye exam that shows a eye problem that could explain their visual deficits, then we can't really make a diagnosis of CVI, for example, if they have like, a severe retina optic nerve problem, then we would have to say that their visual impairment is due to their eye rather than the brain. So it's sort of looking at the whole picture to make the diagnosis,
and then, in know, when you give a diagnosis, Are there levels, like, medically, like, levels of CVI, or is it just, you know, one, like, is it higher or lower?
Yeah. I mean, there's certainly a spectrum, but there is no like, standardized method of quantifying the severity, or, like categorizing the severity, of CVI, and that's another thing that we're working on with our research and other people are working on as well. The NIH is actually funding a CBI registry where people who have CVI can have their data input to the registry. And we're hoping that if we do some like sort of data. Driven analysis of the data that we get into the registry that might help us better understand the different levels of severity of CVI, or how to best categorize it.
And then, I mean, you already went over the difference between CVI and other vision impairments, but what about like vision processing disorder? Do you have any info on, like, how they can determine the difference between that and CVI?
Yeah, I guess I don't really know of like, a standard definition of visual processing disorder, and CVI itself is a disorder visual processing. So it's hard for me to say exactly how if they are actually different diagnoses, or how to distinguish them.
Okay, so, how can you describe like, what a person who has CVI is experiencing and seeing like, what? What does that look like? Are they because I was reading someone's someone who asked you guys, they've written an article, they say, like, they see the floor as lava, or, you know, obviously it's a spectrum. Everyone is different. But like, what is a typical way that they, you know, they they see or they don't see.
So, like, the more severely affected, they might only see lies or shadows or movement. Those who like have better visual acuity and also better cognitive status, so they can tell us what they see. Sometimes have described their vision like a kaleidoscope or like a Picasso painting, where they like see all the different parts, but they like can't put them together as a whole.
Okay? And then, because it's obviously something happening in the brain, how does that affect other senses? Like, do they usually have other co occurring, like symptoms or challenges that come about with it? So
that's a really interesting question. There is one of my colleagues at Boston, or I guess Harvard Medical School is studying sort of like multi sensory integration, so audio visual integration, and people with CVI, we don't really know very well how other senses are affected, but they do. If they can hear like if they don't have another like a genetic problem that also causes hearing loss, then they tend to be more reliant on other senses, such as their hearing.
Does it affect how they develop and grow over the years as a child is getting older?
I think so. Again, there's not, like a ton of data, but we do think, we do know that kids who have visual impairments have a higher rate of, for example, autism, and we think that if they can't see well, then they can't really learn social cues or communication, and so they have difficulty developing in that way. That is, I think, the main area that has been studied, but it probably affects development on many different levels, for example, like it may take them longer to walk because they can't see as well to walk.
Then going back to the signs and symptoms, like, if a parent is reading this and they're wondering, oh, my child is, you know, showing this one symptom, you know, if it's a baby, what else would you say they should maybe look out for, like, to observe the baby and see or or toddler, or whatever, however, whatever the child is. But are there anything else that are kind of like, Whoa, those are signs of CVI. Yeah.
Any signs of visual impairment in general, babies are like, not tracking, not looking at your parents face. For CVI, often they have it takes them longer to make a visual response. We call that latency. So if you show them something, they don't look at it immediately. They they like takes a few seconds for them to look at it. They may like to stare at lights, which can also happen in other like ocular visual impairments, they may prefer seeing things that are bright colors, high contrast, bright lights, because those things are easier for people with CVI to see.
And then moving into kind of like after diagnosis. What are usually, you know, you diagnose a child, what are the steps that a parent should be prepared for after? Is it, you know, moving to a treatment, or do they get some kind of accommodation or device or something to help them? Like, what are you really the steps after?
Yeah, so they should have a functional vision assessment, like, some way for us to better understand how they use your vision everyday life, not just like in the clinic. One of them is like, called the CVI range. There's another one that's called the CVI protocol, I think, by Perkins, and that can help guide interventions. So they should definitely see a teacher for the visually impaired. And. Teacher for the visually impaired will determine what accommodations are best to help them to access their educational material, whether it be enlarged print, etc, sitting closer to the board. Also, they may benefit from seeing an orientation and mobility specialist to help them learn to navigate based on their level of vision, and at least here in LA, these services usually come through like regional center for the intervention, like before the age of three and after that, through the school district. So we communicate with those, I guess, organizations, and try to add patients to be able to get the services that they are needed. But right now, again, there's no medical treatment, so mostly that interventions are aimed at trying to maximize their use of their vision so that they can function as well as possible with their level of vision. And one thing about CVI, which I think I haven't mentioned yet, is that it does tend to improve over time. So a study actually had a CHLA showed about 80% of kids with CVI did improve their visual function over time. It doesn't usually normalize, and it takes years. It takes a long time, but it does tend to improve, and we think it's due to like, neuroplasticity within the brain.
And is that like a natural occurring thing, or do they have to Are there exercises that are recommended that you know they do at home or or is that just a naturally occurring thing, the
naturally occurring thing. We think just with normal visual environment, people have tried various types of stimuli, visual stimulation, like with bright lights, bright colors, that kind of thing, but has never really been shown like a controlled trial to be effective. So we don't really know if it works or how well it works.
I got it. And then, yeah. I mean, are there any it seems like the medical aspect is not as heavy as doing more of the like, accommodations and things to help them, like, with ONM, like, is that kind of what you're seeing with with your children that you treat?
Yeah, I would say it's a very multidisciplinary disorder. Most of our patients are morbidly disabled, so need to see neurology, maybe neurosurgery, medical genetics. TB, eyes, O and MS, OT, PT, speech language pathology. They have a whole care team, so it's really important for parents to, like, find the right care team and for them to be able to communicate with one another, to be able to provide the best care for the child.
Thank you. And then last question, any other tips you have for families who are just getting started you know their child is diagnosed or any like, any last words for parents, tips for them, if their child has CVI, I
would say I hear a lot that the diagnosis is delayed, and again, I hope this is like decreasing, but there has in the past been not a knowledge, not a lot of like knowledge about CVI, or awareness of CVI in the community. So if parents suspect their child has CVI and their like, local optometrist or ophthalmologist is saying they don't really think so. Like, I would encourage parents to get second or third opinions to you know, help them better understand what's happening, because parents know their children best
well. Thank you so much. Dr Chang, those are all my questions. So the next steps will be writing the article. I'll put in, you know, quote, put quotes and video clips from the interview, and then I'll send that to Marlon, and then we'll just need you, if you have time to review, we just want to make sure you know everything is correct. And then I can send you the public key published article next month. So okay, yeah, great. Thank you so much.
We look forward to it. Thanks, Adelina, thank you. Thank you. Dr Chang and Marlon for connecting. Yeah, bye, bye, bye.
