14 Assessment in children who are blind or visually impaired

Cautionary note: It is important to highlight that competency in assessment with children who have visual impairments involves much more than making adaptations to tests. Specialized training in vision is important to understand the impact of vision on development, provide the appropriate adaptations, interpret results, and make appropriate diagnoses and recommendations. This chapter is designed to be an introduction to visual impairments for psychologists who are interested in learning about  assessments with children who are blind or partially sighted. Extensive resources for further learning are provided for those clinicians who are interested in developing competency in this area. Children in British Columbia, the Yukon, or the Northwest Territories, Canada with visual impairments may be referred by their medical doctor to the  Sunny Hill Visual Impairment Program. 

Comprehensive information

For extensive background information on visual impairments, and details on how to assess children with visual impairments, please see the free online course Psycho-educational Assessment in Children with Visual Impairments.

Development and assessment of vision in children

In early childhood, vision is still developing. Maturity in vision usually occurs around age 6 to 8. An ophthalmologist uses a fundoscopic evaluation to examine the anterior visual pathway (from the eye to the lateral geniculate nucleus of the thalamus).  This type of evaluation can identify about 60% of visual impairments. The posterior pathway includes the optic radiations and the occipital cortex of the brain. Problems in the posterior pathway rarely occur in isolation. They often occur with anterior pathway problems or other developmental issues.

Visual conditions

Various vision conditions are common in children with neuromotor disorders and multiple, severe disabilities. For a list of visual conditions and their potential impact on education, see here. Following are some common categories of visual impairment:

• Problems with visual acuity, or sharpness of vision, may be present. Children who have visual acuity of 20/70 or poorer (with correction) qualify for the designation of “visual impairment” for special education purposes. For context, 20/200 (with correction) is considered “legally blind.” Children with visual acuity difficulties need material brought closer or enlarged. Children with acuity of 20/80 in general need information presented 4 times larger, or 4 times closer, than someone with 20/20 vision. 
• Strabismus is a condition where the eyes look in two different directions. The misaligned eye may look inward (esotropia), or outward (exotropia). Untreated, it can lead to amblyopia (sometimes called “lazy eye”) and severe visual impairment in the affected eye.
• Cortical Visual Impairment (CVI) can result from damage to the occipital lobe or pathways between the eye and the occipital lobe. Children with CVI have an abnormal response or reduced response to visual input. CVI tends to improve with development. Children with CVI benefit from reduced visual clutter, and use of high contrast materials.
• Visual field loss can occur due to damage to the visual pathways in the brain. This can include specific field cuts (e.g., upper left field cut), or a reduced field of vision (e.g., loss of peripheral vision in both eyes). Hemianopia (also called hemianopsia) is the loss of half of the field of vision and can result from brain damage to the optic tract or occipital lobe. This can impact one or both eyes. Commonly, you will see “homonymous hemianopia.” More details on assessment in children with homonymous hemianopia can be found in the next chapter.
• Difficulty with control of eye movements can impact functional use of vision.
• Problems with depth perception “stereopsis” are common in children with multiple, severe disabilities, but this should not impact typical psycho-educational testing.

General set up, optimizing vision & adaptations

• For children with visual impairments, it is often mentally draining to engage in visually-demanding tasks. Furthermore, the ability to see over the course of a day varies with level of fatigue, attention, familiarity, and lighting conditions. Eye movement issues, esotropia, exotropia, nystagmus, may become more impairing as the child fatigues. For this reason, it is helpful to alternate visual and verbal tasks and to provide lots of breaks.
• Pay attention to lighting, glare, and shadows. Some children need low light, while others need bright light. It can be helpful to have a table lamp available instead of (or in addition to) overhead lights. Watch for glare off of materials. Baseball caps can be good for glare and light sensitivity. Watch for shadows on the work area (a slant board can help with this).
• For visual items, consider placing the material on a book stand to bring the material closer to the child. You could also prop it up on a pile of boxes or books (see photo). The material should be at eye level of the child. This is to bring the material closer to the eye without producing neck strain.  Use caution when turning the pages so that you do not hit the child in the face.
• I like to start off by telling children that I am not trying to test their eyesight. If they have difficulty seeing ANYTHING during the assessment, it is important that they let me know. However, some children cannot or will not tell you if they are having difficulty seeing. If you have concerns about the child’s ability to see details correctly, it is important to check with the child. When the discontinue is met, go back to an item where they made an error, and ask the child to describe exactly what they see. Ask the child to describe what they see rather than ask, “can you see this?”. Pay attention to possible problems with color vision, mislabeling, missing details, etc. When tests are challenging for the child to see (when they can see but it is effortful), consider whether these tests are necessary to administer. Realize that they may not be a measuring what the test was designed to measure. For example, the WISC Processing Speed tests may not be a good measure of mental processing speed if the child has difficulty seeing the shapes. However, a score on these tests can give you a measure of how fast a child is likely to finish visually challenging written worksheets in the classroom compared to their peers.
• Observe how the child scans the page, do they scan in an organized manner; are they missing parts of the page? Some children with visual difficulties have difficulty with visual attention and visual search strategies. They may need support/reminders to attend to all aspects of the page (“look here, look here”).
• Many children with visual impairments (particularly children with cortical visual impairment) benefit from increasing contrast. Consider using a black contrast mat (“desk blotter”) to increase the contrast between test materials and the table. This also helps to focus visual attention on the testing materials. Pay attention to contrast on other test materials and how this may impact the assessment. For example, an early item on WPPSI Block Design asks the child to look at a picture of white blocks on a white background. Also, the Stanford Binet three-hole puzzle has no contrast in the puzzle pieces space. You could consider using a black “inset” in the puzzle to increase the contrast.
• When a task is “visually crowded” (e.g., the last page of the Visual subtest on the Beery VMI) consider isolating individual items by covering up irrelevant parts.
• For children with visual impairments, it is still important to assess visual learning and reasoning. For some children with visual impairments, vision may still be their strongest learning channel. However, if a child with visual impairments has difficulty on tests with high visual demands, we must consider the results a minimum estimate of their functioning.
• In addition to the typical areas of functioning, be sure to assess listening comprehension as this is an important skill for children with visual impairments who rely heavily on their listening skills.
• Using an enlarger, such as a magnifier, increases the working memory demands of the task as the child has to integrate multiple “parts” into a whole. Rather than being able to see and “take in” the whole of the picture, they must look at each part separately and then mentally integrate the parts. This inherently makes most visual tasks more challenging and this should be taken into account when interpreting your findings. Similarly, children who see only through a small visual field  (or who have spots of loss such as in scotoma) will need to work harder to integrate the things that they see.
• For children with visual impairment, it is important to be aware of the impact of sensory loss on development. Children with limited vision have reduced access to incidental learning. Be aware of how sensory (and motor) impairments may have limited an individual’s exposure to certain concepts/pictures. For example, someone who is blind may not have had the experience of using something like chalk, an item with which most North American children would be familiar. Thus, asking how chalk and a marker are alike would present an unfair challenge.
• Children with visual field loss may show specific errors on testing related to their visual condition. For example, on WISC Picture Span, the child is asked to memorize a series of drawings of objects. Examination of the child’s pattern of errors may show that a child with left field loss does not recall the item on the far left.

Academic testing

• Be aware that for braille learners, the expected progression of numeracy, reading, and writing, are not the same as the progression of the same skills in sighted peers.
• Be aware that reading, for individuals with a visual impairment, is likely to be slower. Reading enlarged materials takes more time. Reading small text takes more effort, and therefore more time. If a child with visual impairments has no difficulty with accuracy and reading comprehension, slow reading speed should not be considered a learning disability, but rather should be considered secondary to the visual impairment. Even experienced braille readers are typically slower than print readers. They will require extra reading time for tests due to their visual impairment.
• If needed, enlarge reading materials ahead of time of. Be sure that the copies have high contrast (you can adjust the contrast to the highest possible on the photocopier). With photocopies, make sure you present only one page at a time, so that there is no interference from text showing through from the page underneath.
• Right (compared to left) homonymous hemianopia has a stronger impact on reading as the person is not able to preview the upcoming letters, particularly impacting reading beyond the single word  stage and causing a decrease in reading speed. Left homonymous hemianopia can also impact reading by causing difficulty finding the next line of text and causing word reading errors as the first letters of the word may be missed.
• To support children who have low vision when writing during an assessment, it is appropriate to provide the child with whatever adaptations they normally use for writing. You may want to use paper with thick black lines (free printable pdfs are available online). There is also paper with raised black lines available for purchase. Give the person a dark thin pen or marker to write with to increase contrast.