Written by: Rachel Bennett
Access the video transcript.
At Perkins, we are a gathering place of ideas. The CVI visual behaviors synthesize current research and build on the work of leading theorists in the field. CVI is a lifelong disability and we want to ensure that all individuals with CVI are fully understood. The CVI visual behaviors are an ongoing need, they can change and they can improve for some, but the need never goes away. No one area is separated from the other—the CVI visual behaviors are highly connected and all can impact the individual with CVI at any time.
When our eyes are in a fixed position straight ahead, the area that we see is called a “visual field.” Visual field loss happens when a portion of the visual field is absent. People with CVI can have a range of visual field deficits, depending on where the damage or interruption happens in the brain. For example, damage on the right side of the primary visual cortex in the occipital lobe may cause left homonymous hemianopia or field loss in the left side of each eye.
This CVI impact area encompasses visual field access (peripheral and central) as it relates to awareness, established and/or maintained attention, and recognition.
Some people with CVI may have:
Visual field access may be further impacted by: reduced contrast sensitivity, ocular motor challenges, visual motor difficulties, visual clutter, competing sensory stimuli, visual fatigue, and motion in the environment.
I have trouble with my lower visual field. I like things to be put up on a slant board so that I can see it better. I can see some things that are higher in my visual field, but it depends on which side it’s on. Higher up on the left is a problem.Young adult with CVI
Many with CVI build strategies to compensate for visual field loss and changes in visual field access in a given moment or situation. Some of these strategies include:
When I’m rested and happy, I see clearly except for the visual field loss. My acuity is fine. But, when I have visual fatigue, it’s like looking through a straw. I have an extremely limited visual field. It gets all fuzzy. Usually, when I’m not fatigued, it’s like looking through an empty toilet paper roll.Dagbjört, an adult with CVI, from Why Music is My Vision
When it comes to observable behaviors around visual field access, some people with CVI may:
Some questions for observation for individuals who navigate by walking and/or using equipment such as a wheelchair and/or gait trainer:
It’s hard for me to get around sometimes. People cut me off in stores, especially when they come on the right side because I can’t see anything on that side. I am always surprised. I’m like, “Oh my god, where did you come from, I can’t see that?!”-Chloe, young adult with CVI, from the CVI Voices video
All accommodations must be based on assessment. The following are meant to inspire and provide a general idea. Accommodations and instructional approaches must be student-specific. Access is individual.
Find more examples from a guide to common CVI IEP accommodations in the CVI Now IEP Guide.
When my son interacts with items or watches videos on his iPad, I can tell he’s favoring his upper right field. His head is tilted and turned toward the left. Sometimes he puts his head down on the table on his left side when playing with his toys. When walking and going up and down stairs, he never uses his lower field and uses his compensatory and blindness skills to navigate like his white cane, toe-tapping, holding on to me, or the railing.CVI parent
Connecting current research of the brain, our visual system, and CVI to better understand the CVI visual behaviors.
According to Chockron, Klara, and Dutton (2021), with a CVI, there can be a range of visual field deficits:
Research shows various ways visual fields can be affected: Lesions or dysfunction affecting the optic tracts, lateral geniculate nuclei, optic radiations, or primary visual cortices can cause visual field loss (Lueck & Dutton, 2015). The superior optic radiations can also be affected, causing lower visual field impairment, which ranges from being complete to solely rendering the feet invisible when walking (Chokron & Dutton, 2016).
Effects of visual field deficits may include impaired visual motor coordination and difficulties in reading and social interaction (Chokron, et al. 2021, Jacobson and Dutton, 2000; Fazzi et al., 2009; Pawletko et al., 2014).
Visuospatial neglect, or visual inattention, is the difficulty of detecting or acting upon visual stimuli on one side of space. This is different from visual field loss in that full visual fields are available, but the brain does not give the attention needed to be aware of visual stimuli in a specific visual area. The person with CVI may behave as if half of space on one side does not exist. For example, if there is damage or interruption to the right posterior parietal lobe, then there may be visual neglect or inattention to the left-hand side. Increased clutter and visual stimuli density can make visual neglect more severe (Nijboer and Stigchel, 2019).
Berryman, A., Rasavage, K., & Politzer, T. (2010). Practical clinical treatment strategies for evaluation and treatment of visual field loss and visualinattention. Neuro Rehabilitation, 27, 261-268.
Chokron, S. & Dutton, G. N. (2016). Impact of cerebral visual impairments on motor skills: Implications for developmental coordination disorders. Frontiers in Psychology 7(1471), 1-15
Chokron, S., Klara, K., & Gordon D. (2021). Cortical Visual Impairments and Learning Disabilities. Frontiers in Human Neuroscience 15, 573.
Lueck, A. H., & Dutton, G. N. (2015). “Intervention Methods: Overview and Principles.” A. H. Lueck & G. N. Dutton (eds). Vision and the Brain: Understanding Cerebral Visual Impairment in Children (pp. 497-536). New York, New York: American Foundation for the Blind Press.
Jacobson, L., and Dutton, G. N. (2000). Periventricular leukomalacia: an important cause of visual and ocular motility dysfunction in children. Surv. Ophthalmol. 45, 1–13. doi: 10.1016/S0039-6257(00)00134-X
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Nijboer, T. C.W. & Van Der Stigchel, S. (2019). Visuospatial neglect is more severe when stimulus density is large. Journal of Clinical and Experimental Neuropsychology 41(4), 399-410.
Philip, S.S. and Dutton, G.N. (2014), Cerebral visual impairment in children: a review. Clin Exp Optom, 97: 196-208. https://doi.org/10.1111/cxo.12155
Roman-Lantzy, C. (2018). Cortical Visual Impairment: An Approach to Assessment and Intervention. 2nd ed., New York, NY: AFB Press.