Vision & Mobility
The Impact That Eyesight Can Have on Successful Mobility
- By Laurie Watanabe
- Mar 01, 2015
Watch where you’re going! From infancy (as we toddle toward stairs) through childhood (as we chase the dog through the kitchen) into adulthood (as we weave through a Starbucks while carrying a Mocha Light Frappuccino), we’re told to look out while we’re moving.
But this natural warning can have a different meaning to people who are blind or visually impaired — and vision can add a complex wrinkle to the equation for members of a seating & mobility team. Like able-bodied people, wheelchair users experience vision loss. But the causes and potential solutions can be very different from what other healthcare professionals encounter.
How Common Is Visual Impairment?
It’s understandable, given the myriad of topics to discuss, if a client’s vision is not a primary consideration of a mobility assessment.
But seating & mobility clients can have vision impairments that significantly impact the way they use their wheelchairs.
Angie Kiger, M.Ed., CTRS, ATP/SMS, marketing channel & education manager for Sunrise Medical, says ATPs and clinicians should be prepared to encounter a number of different types of vision impairments when working with clients.
“The American Federation for the Blind quotes a statistic: that up to 40 percent of the brain is utilized to receive, interpret and translate information into visual images,” Kiger explains. “So it’s not surprising that a lot of diagnoses that we work with — traumatic brain injury (TBI), cerebral palsy (CP), any sort of brain injury — would have vision affected also.”
“Vision impairments are largely under diagnosed,” says Magdalena Love, OTR, ATP, clinical education specialist for Permobil. “If a client doesn’t have a dog or a cane, oftentimes we don’t assume they have visual impairments. However, due to the nature of the visual system spanning across many parts of the brain, oftentimes there are visual impairments with neurological conditions. Some research estimates that following a TBI, up to 80 percent of individuals experience some sort of visual disturbance. This resolves itself oftentimes, but about 30 percent of individuals experience lasting visual impairments that need to be addressed.”
These impairments differ from the issues we think of when we generically discuss problems with eyesight, such as nearsightedness.
“Common visual issues addressed following TBI/stroke include diplopia (double vision), visual field cut, visual inattention/neglect, and various visual processing disorders,” Love says.
“I would see cortical visual impairment with my clients with cerebral palsy,” Kiger says. Adding to that challenge: “The hardest part for individuals with cerebral palsy is a lot of them are non verbal,” she notes, which means they aren’t always able to explain to the seating & mobility team what they can and cannot see.
Vision Impairments with Different Causes
Vision is a complex topic, in part because multiple bodily systems are involved.
“I like to split the visual system up into three parts,” Love says. “I think of them almost like parts of a computer. The first part is input, like your keyboard or your mouse. And then you get the throughput, the actual workings of the computer, the hard drive and the software. Then you’ve got your output, whatever you see on your screen.
“The vision system is kind of like that, so I think of vision disorders in that sense. There could be some input problems — let’s say you’ve got myopia (nearsightedness) or hyperopia (farsightedness), which are some of the normal things that we could need glasses for. That is an input problem; the shape of the eye is malformed, so when light goes through the lens, it’s either behind or in front of the lens. But when we talk about brain injury or someone who has not had a chance to develop a normal visual system, there can be a lot more issues.”
Love adds that she doesn’t usually focus on visual acuity— aka, clarity of vision — during the evaluation “because that can be easily addressed with a single referral. But [when I] do a brief acuity screening, that can tell me, Wait a minute: something’s atypical. I should refer out. It could be just that the eye is misformed and [the client has] hyperopia or age-related presbyopia, which is what happens when we need reading glasses around [age] 40 or 45.”
The real challenge, Love says, is that vision problems aren’t always detected when the client is in a rehab facility.
“They’re not found out until somebody really goes out into the community. Because if you think about your routine in the morning — brushing your teeth, getting yourself dressed — you can do those things in complete darkness. So a lot of times those scores in in-patient rehab don’t catch vision problems if people don’t need a cane to get around. Then they get home, and they have a power chair, and now — they’re running into walls or having trouble finding curb cuts or things like that that weren’t caught in in-patient rehab.”
Detecting Potential Vision Impairments
Love acknowledges, “In today’s clinics, there simply is not enough time to complete a comprehensive visual assessment for every person who is getting a seating and mobility evaluation.”
Still, she says ATPs and clinicians can do basic screenings.
“Asking clients to complete a ‘functional acuity’ test identifying print/objects at both near and far distances can be helpful,” she says. “I also liked to do some sort of scanning test, such as identifying how many exit signs, fire hydrants, posters, etc., are in the room. If the individual is unable to easily complete these tests, it will cue me to dig deeper or refer them to an optometrist who specializes in visual development — College of Optometrists in Vision Development (COVD) certification, ideally — for a more complete evaluation.”
Kiger starts observing a new client even before they formally meet.
“I would walk into the therapy room or the waiting room at the hospital, and I wouldn’t necessarily introduce myself, especially if the child was looking at the TV,” she says. “Sometimes, the kid would be looking off to the corner, but actually smiling and engaging with the TV. So that tipped off to me that there’s something going on with vision. You have to be careful, because they might be completely visually impaired and just reacting to sound. But clearly, there’s something going on.”
She also looks for cues in how the client positions himself.
“Why are they constantly turning their head in one direction? Why are they looking up or looking down? If someone is constantly fighting to get into a certain position, are they visually attending to something that you don’t notice because you’re looking head on at it? They’re seeing maybe a glimpse of color — maybe they have a visual field neglect.”
Strategies for Raising Success Rates
While many vision impairments may not be resolvable, Kiger says there can be ways to help clients compensate.
“I’ve done little things in their environment, especially if it’s a long-term care facility or at school,” she notes. “I find out what colors or what areas they see the best. If you have somebody who has a left-side field neglect — they can turn to see, but you’ve got to remind them to turn their head and look in that direction — I’ll take duct tape or painter’s tape in a bright color that I know they react to and put that on that side of the wheelchair. I’ve lined the left footplate with it so it triggers ‘Oh, I’ve got to remember to look at this’ for the client.
“And at home, can you take painter’s tape and make a line down the hallway so they’re able to highlight where the different boundaries are?”
If the client uses vision aids, Kiger wants those aids present at the evaluation: “This might sound completely basic, but when doing an evaluation, especially on someone who is non verbal, ask the caregivers if they have glasses. If they do, bring them to the evaluation. I’ve been at evaluations when we start asking about hearing and vision, and it’s ‘Oh, yeah, they wear glasses at school.’ Great, do you have them? ‘No, we didn’t bring them, they’re at school.’”
Asked how ATPs and clinicians can raise the chances that clients with vision impairments will be successful wheelchair operators, Love says, “The most under-utilized technology: training! Specific mobility training has shown to improve success with mobility goals in both children and adults following stroke.”
In fact, in very young children, vision impairments may be due to lack of independent mobility experience.
“The visual system does not fully develop without independent mobility,” she explains. “This is vital for children especially. The very visual and motor skills that are required to be ‘safe’ at power mobility driving actually develop through having access to independent
Those skills don’t develop nearly as well if the child has to rely totally on dependent mobility.
“The brain is more actively involved in navigation tasks when you are independently doing it yourself,” Love says. “When it comes to kids, depth perception, what steps actually mean, what any obstacles actually mean — none of that stuff is normally ingrained in us. It’s an experience-driven brain development.
“There have been studies — Karen Adolph is the PT who headed them — about ‘fake’ cliffs. Toddlers who just started crawling would be on one side [of the cliff] and the moms would be on the other side, saying, ‘Come on, Baby, come here.’ And the kids would just waltz right over it and not even register that there was a cliff. Then they’d bring them back just a little bit later, when they’d had more experience with crawling, and now these kids were hesitating at that cliff edge: ‘Wait a minute, that is a drop-off. It’s not safe for me to go.’”
Research has proven, Love says, that visual skills and independent mobility go hand in hand.
“If kids don’t have access to navigating their environments and connecting the visual information with safety and mobility, those skills just won’t develop,” she says. “If you get these kids who’ve been in [dependent mobility] chairs for years and then you put them in a power chair and you see they’re not safe, they’re running into walls, it’s not necessarily because they don’t have the potential to be safe. They just haven’t had the chance to explore their environment and learn: ‘Hey, this is what a wall does, this is what a step does, this is how I turn and navigate through a doorway.’”
The same can apply to stroke patients striving to regain function. “We’ve put a lot of our stroke clients into these low, hemi-height chairs, but it’s not functional,” Love says. “They can’t go over high-pile carpet, they can’t get over thresholds, and a lot of times it’s so exhausting that their [spouses] just push them around wherever they go. And [the patients] don’t actually need to use their visual systems. You’ve got these clients with field cuts that are continually running into walls. With some very specific training you can see improvement even with individuals following stroke with visual impairment. The research is showing that.”
The take-away seems to be that vision impairment should not prevent a client from having the opportunity to be independently mobile. With proper help and training — such as from an Orientation & Mobility specialist (see sidebar), even a client with significant vision limitations might learn to be an independent wheelchair user.
Kiger recalls an assistive technology supplier telling her about one of the first clients he ever worked with: a man who needed his power chair adjusted, and just happened to be blind.
“He was asking [the client], ‘Can you see this color on the LED screen?’ The man said no; he was completely blind. The supplier said his knee-jerk reaction was Oh my gosh, you’re driving a power chair?
“But the client drove the chair better than anyone he’s ever seen in his life.”
This article originally appeared in the March 2015 Mobility Management issue of Mobility Management.