Cerebral visual impairment: Screening, referrals, and what's next

Cerebral (or cortical) visual impairment (CVI) is now the leading cause of pediatric visual impairment, but many eye care providers still aren't sure what to look for or what to do when a child's visual behavior doesn't match their exam measurements. Jem Martin, OD, of the New England College of Optometry (NECO) Center for Eye Care at Perkins School for the Blind, argues that general eye doctors can play a meaningful role in identifying and supporting these children—often without managing the full workup themselves. In this Q&A, Martin discusses the accommodations and referrals any provider can offer, the red flags that should raise suspicion of CVI, how the free TEACHCVI screening tool works in practice, where CVI research and diagnosis are heading, and a patient encounter that captured why accessible, individualized care matters so deeply.

When diagnosing CVI, what should a general eye doctor be thinking about in terms of accommodations or referrals, even if they're not managing the full workup?

Jem Martin, OD: Absolutely. I think a big thing that I have found that a lot of folks in the eye care world, be it optometry and ophthalmology, don't fully realize is how much they can easily bridge a lot of the educational aspects. So as easy as just providing recommendations for print size, or recognizing that there may be variable use of vision, or even just saying there's resources regarding this. Providing that to the family can be a great first step, as well as recommending educational evaluations. So things like work with teachers [of] students with visual impairments( TVIs), orientation mobility specialists (ONMs), [or] assistive technology are all things that we, as eye care providers, can do to connect with the patient and with their needs that extend far beyond the examination space.

What red flags in a routine eye exam should make a doctor suspect CVI and refer out?

Martin: I think our leading recommendation is always the thought that the use of the vision doesn't match the measurements that we're getting in the examination; the functional vision doesn't match the visual function. So again, someone with CVI could have significant issues with detecting motion. I've had individuals say that instead of seeing things move very smoothly towards them, it appears more like a stop-motion type issue, and they become anxious, say, crossing the street, because they can't anticipate how fast the car is coming, where it's going to appear next, and be able to cross safely. And these issues are reported by someone who has 20/20 visual acuity without glasses, no need for glasses, who have full visual field contrast sensitivities, excellent depth perception measures, and yet crossing a road is a huge issue. This is of course just one example, but similar in thinking: if you have really good visual measures and they're not following along with how the individual is using their vision, do they instead prefer to use their tactile or even auditory sense and not use vision at all and start to look away when reaching for things or not engage that use of vision? [Those] are also some of these red flags. So, always thinking about the big ones being a variable use of their vision, looking away or not looking away when reaching for objects, as well as difficulties with visual novelty or visual clutter compared to things that are more simplified and things that are more visually familiar to them.

For eye care providers who haven't heard of it, what is TEACHCVI, and how could an OD actually use it in their own practice?

Martin: The TEACHCVI is a type of visual questionnaire survey about how an individual may be using their vision, specifically meant to screen for CVI. So, we can find this on TEACHCVI.net. Totally free and accessible across the board, but this is our survey of choice at the NECO Center for Eye Care at Perkins [School for the Blind], mainly because it allows us for a lot of flexibility, which has always been our ethos in approaching our access to visual care.

So, with the TEACHCVI survey, there are 3 different levels, the first level being for individuals who are not ambulatory, so any questions about taking stairs or things like that are not asked. The level 2 is for a developmental age from 2 to 6, and then the level 3 is for a developmental age from 6 to 12… So, for instance, we would want to make sure that the questioner that we select is asking questions that are appropriate to the child in their developmental age. So, for instance, something that a 13 year old would be doing might not be applicable for a 2 year old, and can guide that selection in using between that level 2 and level 3 task. From there, each of the questions questionnaires have a series of questions ranging from 19 to 45 questions, depending on the level chosen, and asking about different aspects of visual behavior: How are we doing in visual clutter? Are we able to look at and perceive moving objects or people, do we have difficulty experiencing variable use in vision? Just a lot of areas across both the ventral stream or that identification access of the vision and that dorsal stream or like the where pathway or where objects are spatially located, and understanding the areas of the use of vision that the individual is having difficulties with.

As a screener, I think it's really great because once you find it, you can count up all the numbers, and depending on if we hit a certain threshold, we can then start to suspect: Do we have a diagnosis? Is it possible that these visual behaviors are explainable by a diagnosis of cerebral visual impairment, and then from there we can start to think about providing referrals to those who are able to provide that diagnosis, and then can take those next steps. I think it's really great and user friendly, and we continue to use it at our clinic.

To then further ask questions about when these visual behaviors are happening: is it related to the use of vision? Is it potentially related to another diagnosis or another aspect happening in the environment that wasn't initially reported? And we can also start to think about the areas that are important to the family. Once we make those recommendations, be it a diagnosis or not, we can make sure that we're providing recommendations that directly address the parental concerns, as noted by the survey.

Where do you see CVI diagnosis heading in the next several years, and what would you like to see in how it's identified and assessed?

Martin: What I think is awesome is right now the National Eye Institute branch of the NIH is working towards starting to have a longitudinal assessment of individuals with CVI–a little bit of a natural history both between them as well as the [Pediatric Eye Disease Investigator Group, or] PEDIG group, which is a PEDIG eye disease information group that guides a lot of the clinical guidelines for how we treat just general pediatrics in vision. So both of these huge groups have kind of started to put CVI within their radar, and I think that that has started to speed up a lot of the kind of research in this area. The importance to start thinking about what do we absolutely need to come to a diagnosis of CVI and come to that consensus for both diagnosis as well as what treatment and management can look like. A lot of these places are areas that don't have necessarily a consensus, but it is nice to see a lot of the big names that are working towards vision healthcare from across the country is really great. That way we can see how do we expect CVI to naturally progress, and then start to understand what interventions are very beneficial for this population to better guide the support we can provide for them.

Is there a moment or a patient interaction that stuck with you? Something that captures why this work feels so meaningful?

I always think back to a time when I was a resident. We had worked up a child coming in. We knew that they were not speaking and I was like, “We're going to do either like some matching things where they can point, or maybe preferential looking tests where they just have to direct their gaze at a certain direction, and to get the examination information.” So I was having that type of examination approach in mind. And then my mentor, Dr Barry Kran, OD, FAAO, comes in, and they're starting to set up her AAC–her augmentive alternative communication device. So a little iPad, lots of little buttons on it that allow her to communicate. They hook it up to her wheelchair while I'm focusing on getting things sorted on the other side of the room, so I'm not fully paying attention. But I hear Dr Kran come up and he says, "Hi, what's your name?” And I'm like, "That's weird. The whole time we were talking about how she doesn't speak,” but then immediately he's like, "Hi, my name is–“ and then I turned around and really took in her way that she communicated with this AAC, and it wasn't even by touching; it was through her eye gaze. So they had it set up on her chair, and it detected where her eyes looked, and if it looked for a long enough period of time, it would make that selection. And a lot of the work they were wondering about using the eye gaze with her is that they wanted to increase the number of options she had to select on a page.

A big thing that we see in CVI is the impact of visual clutter, and adding more things, especially new things, can reduce the way that vision can be used; be it the way vision can be used, be it the amount of side vision we have, or peripheral vision, or the amount of acuity, and things start to get blurry. Many things can have been reported for these individuals, but when looking at her device, what we did was move things around and added a couple of squares in there, and started talking with her. And what we saw was that she was using muscle memory to go to where she knew where her name was going to be, and when it didn't put that output, she immediately became very upset, very agitated. We changed her communication device and quickly, of course, set it back up for her, and calmed her back down, had some Peppa Pig going on the TV, things like that. But really, seeing the impact, that even the way that we can assess things and the impact that the functional use of vision can have for individuals across a spectrum of abilities, and making sure that we maintain things that are accessible, so they can remain as independent as possible.