CVI
Cortical Visual Impairment (CVI) is visual dysfunction caused by damage to or impaired functioning of cortical structures, despite intact ocular structure and function.
CVI is the leading cause of pediatric visual impairment in the US.1
CVI is known to affect children’s learning, especially reading abilities.
Symptoms of CVI:
- Increased attention to bright lights or a noticeable preference for specific colors, such as red.
- Delayed visual responses and difficulties with fixing or tracking objects.
- Reliance on peripheral vision to focus on objects.
- Challenges with navigating changes in walking surfaces, such as reaching out with the foot instead of visually assessing the next step.
- Difficulty processing or navigating highly stimulating visual environments.
Project 8p Foundation Affiliated Research on Chromosome 8p Disorders
While the exact prevalence of cortical visual impairment (CVI) in individuals with chromosome 8p rearrangements remains unknown, there has been a recent increase in diagnoses, indicating it may be a more common symptom than previously understood. Studies and reports provide a clearer understanding of the prevalence range, though results vary depending on the size and characteristics of the populations studied:
- Children’s Hospital Colorado reports 53% of heroes who have attended their clinic receive a CVI diagnosis.
- A 2019 study, Clinical and genomic characterization of 8p cytogenomic disorder reported that up to 55% of 8p heroes experience vision issues.3
If CVI is a concern, collaborating with both ophthalmology and neurology specialists is essential to ensure a thorough evaluation and accurate diagnosis.
When scheduling an ophthalmology appointment, inform the provider if your 8p hero may find it challenging to sit through an exam. Be direct and ask the provider to confirm whether they are able to complete the full evaluation. Pediatric specialists are experienced in working with children and can take additional steps to help ensure a successful assessment.
Standard Screening Questions:
Screening Tools:
Treatment: Vision therapy is recommended when there is a CVI diagnosis. Modifications for the patient can include:
Standard Screening Questions:
- Does the family have concerns about vision?
- How does the patient look at things? Out of the corner of their eye or with central vision?
- How does the patient go down stairs and cross thresholds or uneven surfaces?
Screening Tools:
- Colorado Children’s Hospital recommends utilizing The CDKL5 Clinical Severity Assessment
- Visual components of the scale can be averaged together for a score 0-100 with score of 100 representing the most severe visual impairment
Treatment: Vision therapy is recommended when there is a CVI diagnosis. Modifications for the patient can include:
- Keep the learning environment simple
- Use high contrast images
- Augmentative Alternative Communication (AAC) Devices should be set up with CVI in mind
- CVI modifications should be incorporated into all therapies
- It is recommended to consult with a Teacher of the Visually Impaired (TVI)
- Boston Children’s Hospital. Cortical Visual Impairment (CVI). https://www.childrenshospital.org/conditions/cortical-visual-impairment
- Santucci, K., Malik, K. E., Angione, K., Bennink, D., Gerk, A., Mancini, D., Stringfellow, M., Dinkel, T., Demarest, S., Miele, A. S., & Saenz, M. (2024). Chromosome 8p Syndromes Clinical Presentation and Management Guideline. Availabile At: https://project8p.org/wp-content/uploads/2024/10/Clinical-Genetics-2024-Santucci-Chromosome-8p-Syndromes-Clinical-Presentation-and-Management-Guidelines.pdf
- Okur, Volkan, Chung, Wendy et al. “Clinical and Genomic Characterization of 8p Cytogenomic Disorders.” Genetics in Medicine, https://project8p.org/wp-content/uploads/2023/08/s41436-021-01270-2.pdf.
Roman, Christine, PhD. Cortical Visual Impairment Information and Resources. CVI Resource, https://cviresources.com
CVI NOW: Perkins School for the Blind, https://www.perkins.org/cvi-now/
- What is CVI?
- How is CVI diagnosed?
- Visual Behaviors
- CVI Now IEP Guide – Perkins School for the Blind
- These 9 easy classroom adaptations can help kids with CVI
- Adapting worksheets for CVI
- How to DIY for CVI accessibility: Room-by-room projects
- EI Series:
- Complex Communication Needs
- Communication AAC
Understanding Cortical Visual Impairment
8p Hero Insights
Management and Care Recommendations
Resources
Understanding Cortical Visual Impairment
CVI is the leading cause of pediatric visual impairment in the US.
CVI is known to affect children’s learning, especially reading abilities.
Symptoms of CVI include:
- Increased attention to bright lights or certain colors (for example, red)
- Delayed visual responses, reduced fixing/tracking
- Use of peripheral vision to look at objects
- Difficulty with change in walking surfaces,reach out with foot instead of looking at next step
- Difficulty with highly stimulating visual environments
8p Hero Insights
11% of patients in the Chromosome 8p Registry report CVI.
We believe the actual prevalence of CVI in individuals with chromosome 8p rearrangements is likely higher. This discrepancy may be due to the relatively recent recognition and diagnosis of CVI within the neurogenetic community.
Project 8p Foundation Affiliated Research on Chromosome 8p Disorders
While the exact prevalence of seizures in individuals with chromosome 8p rearrangements is unknown, they are recognized as a common symptom. Studies and reports provide a clearer understanding of the prevalence range, though results vary depending on the size and characteristics of the populations studied:
- Children’s Hospital Colorado reports 53% of 8p patients seen have received a CVI diagnosis.
- A 2019 study, Clinical and genomic characterization of 8p cytogenomic disorder reported 14% of the participating patients reported CVI, while 55% of the participating patients reported vision issues.
Management and Care Recommendations
Standard Screening Questions:
- 4. Does the family have concerns about vision?
- 5. How does the patient look at things?Out of the corner of their eye or with central vision?
- 6. How does the patient go down stairs and cross thresholds or uneven surfaces?
- Colorado Children’s Hospital recommends utilizing The CDKL5 Clinical Severity Assessment
- Visual components of the scale can be averaged together for a score 0-100 with score of 100 representing the most severe visual impairment
- Keep the learning environment simple
- Use high contrast images
- Augmentative Alternative Communication (AAC) Devices should be set up with CVI in mind
- CVI modifications should be incorporated into all therapies
Resources
- Boston Children’s Hospital. Cortical Visual Impairment (CVI).
- https://www.childrenshospital.org/conditions/cortical-visual-impairment .
- Roman, Christine, PhD. Cortical Visual Impairment Information and Resources. CVI Resources, https://cviresources.com
Refractive Errors
Refractive errors occur when the eye cannot properly bend and focus light onto the retina.
Refractive errors are a common vision issue that affects the clarity of sight. They occur when the shape of the eye prevents light from properly focusing on the retina, the light-sensitive tissue at the back of the eye.
Types of Refractive Errors:
- Nearsightedness (myopia): Causes distant objects to appear blurry.
- Farsightedness (hyperopia): Causes nearby objects to appear blurry.
- Astigmatism: Can cause both distant and nearby objects to appear blurry or distorted.
- Presbyopia: Affects middle-aged and older adults, making it difficult to see objects up close.1
Symptoms:
The most common symptom of refractive errors is blurry vision; however, individuals with a chromosome 8p rearrangement may have difficulty expressing this. Additional symptoms to watch for include:
- Frequent squinting
- Holding objects close or getting close to objects when looking at them
- Being frequently startled by nearby objects (indicating the objects were not seen initially)
- Light sensitivity3
Project 8p Foundation Affiliated Research on Chromosome 8p Disorders
While the exact prevalence of Refractive Errors in individuals with chromosome 8p rearrangements is not well established, it is recognized as a common symptom. Research provides a clearer picture of the prevalence range, although results can vary based on the size and characteristics of the populations studied.
A 2019 study, Clinical and genomic characterization of 8p cytogenomic disorder reported 35% of the participating patients reported Refractive Errors.2
Ophthalmologic Evaluations:
Annual ophthalmologic evaluations are recommended for individuals with a chromosome 8p rearrangement to monitor and manage potential vision issues.
Screening for Refractive Errors An ophthalmologist will assess refractive errors through a comprehensive eye exam. Given that many individuals with a chromosome 8p rearrangement may not be able to perform typical eye exam tasks, it is essential to seek an ophthalmologist who has experience working with patients who have developmental and health conditions. These specialists are equipped to perform eye exams on non-verbal patients or those with additional health needs, using adapted techniques to accurately assess vision without relying on verbal responses or other traditional methods.
Nonverbal Eye Exam:
Treatment for Refractive Errors
Screening for Refractive Errors An ophthalmologist will assess refractive errors through a comprehensive eye exam. Given that many individuals with a chromosome 8p rearrangement may not be able to perform typical eye exam tasks, it is essential to seek an ophthalmologist who has experience working with patients who have developmental and health conditions. These specialists are equipped to perform eye exams on non-verbal patients or those with additional health needs, using adapted techniques to accurately assess vision without relying on verbal responses or other traditional methods.
Nonverbal Eye Exam:
- Some individuals with a chromosome 8p rearrangement may engage in a matching game during the eye exam to help screen for refractive errors.
- Cycloplegic Retinoscopy is an effective test that requires no response from the patient. Special eye drops are used to dilate the pupils and relax the eye’s focusing mechanism. After about 30 minutes, the ophthalmologist uses a retinoscope to shine light into the eye and determine if vision correction is needed. This test allows for accurate vision assessment without requiring the patient’s direct feedback. Learn more about this type of exam on the Autism Speaks website.3
Treatment for Refractive Errors
- Eye Glasses
- Contacts Lenses
- Surgery
- National Eye Institute. Refractive Errors.
https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/refractive-errors - Okur, Volkan, Chung, Wendy et al. “Clinical and Genomic Characterization of 8p Cytogenomic Disorders.” Genetics in Medicine, https://project8p.org/wp-content/uploads/2023/08/s41436-021-01270-2.pdf
- Davitt, Bradley, M.D. Nonverbal, Autistic and in Need of Glasses. Autism Speaks,
https://www.autismspeaks.org/expert-opinion/nonverbal-autistic-glasses
Understanding Refractive Errors
8p Hero Insights
Management and Care Recommendations
Resources
Understanding Refractive Errors
Refractive errors are a common vision issue that affects the clarity of sight. They occur when the shape of the eye prevents light from properly focusing on the retina, the light-sensitive tissue at the back of the eye.
Types of Refractive Errors:
- Nearsightedness (myopia) causes distant objects to appear blurry
- Farsightedness (hyperopia) causes nearby objects look blurry
- Astigmatism can make distant and nearby objects look blurry or distorted
- Presbyopia makes it hard for middle-aged and older adults to see things up close
- Frequent squinting
- Holding objects close or getting close to objects when looking at them
- Being frequently startled by nearby objects (indicating the objects were not seen initially)
- Light sensitivity
8p Hero Insights
Project 8p Foundation Affiliated Research on Chromosome 8p Disorders
While the exact prevalence of Refractive Errors in individuals with chromosome 8p rearrangements is not well established, it is recognized as a common symptom. Research provides a clearer picture of the prevalence range, although results can vary based on the size and characteristics of the populations studied.
A 2019 study, Clinical and genomic characterization of 8p cytogenomic disorder reported 35% of the participating patients reported Refractive Errors
Management and Care Recommendations
Ophthalmologic Evaluations:
Annual ophthalmologic evaluations are recommended for individuals with a chromosome 8p rearrangement to monitor and manage potential vision issues.
Screening for Refractive Errors
An ophthalmologist will assess refractive errors through a comprehensive eye exam. Given that many individuals with a chromosome 8p rearrangement may not be able to perform typical eye exam tasks, it is essential to seek an ophthalmologist who has experience working with patients who have developmental and health conditions. These specialists are equipped to perform eye exams on non-verbal patients or those with additional health needs, using adapted techniques to accurately assess vision without relying on verbal responses or other traditional methods.
Nonverbal Eye Exam:
- Some individuals with a chromosome 8p rearrangement may engage in a matching game during the eye exam to help screen for refractive errors.
- Cycloplegic Retinoscopy is an effective test that requires no response from the patient. Special eye drops are used to dilate the pupils and relax the eye’s focusing mechanism. After about 30 minutes, the ophthalmologist uses a retinoscope to shine light into the eye and determine if vision correction is needed. This test allows for accurate vision assessment without requiring the patient’s direct feedback. Learn more about this type of exam on the Autism Speaks website.
- Eye Glasses
- Contacts Lenses
- Surgery
Resources
National Eye Institute. Refractive Errors.
https://www.nei.nih.gov/learn-about-eye-health/eye-conditions-and-diseases/refractive-errors
Okur, Volkan, Chung, Wendy et al. “Clinical and Genomic Characterization of 8p Cytogenomic Disorders.” Genetics in Medicine, https://project8p.org/wp-content/uploads/2023/08/s41436-021-01270-2.pdf
Davitt, Bradley, M.D. Nonverbal, Autistic and in Need of Glasses. Autism Speaks,
https://www.autismspeaks.org/expert-opinion/nonverbal-autistic-glasses
Strabismus
Strabismus is a condition in which the eyes are misaligned.
Strabismus is a common eye condition in children, affecting about 2 to 4 percent of the general population. Strabismus can cause one or both eyes to misalign.
Types of Strabismus:
- Esotropia: Occurs when the eye(s) turn inward.
- Exotropia: Occurs when the eye(s) turn outward.
- Hypertropia: Occurs when the eye(s) turn upward.
- Hypotropia: Occurs when the eye(s) turn downward.
Children may be born with strabismus, or it may develop later in life due to an injury or underlying health issue.
Amblyopia, also known as “lazy eye,” can develop as a result of strabismus because the misalignment prevents normal vision development in childhood.1
Project 8p Foundation Affiliated Research on Chromosome 8p Disorders
While the exact prevalence of Strabismus in individuals with chromosome 8p rearrangements is not well established, it is recognized as a common symptom. Research provides a clearer picture of the prevalence range, although results can vary based on the size and characteristics of the populations studied.
- A 2019 study, Clinical and genomic characterization of 8p cytogenomic disorder reported 19% of the participating patients reported Strabismus.2
Ophthalmologic Evaluations:
Annual ophthalmologic evaluations are recommended for individuals with a chromosome 8p rearrangement to monitor and manage potential vision issues.
Screening for Refractive Errors An ophthalmologist will assess strabismus through a comprehensive eye exam. Given that many individuals with a chromosome 8p rearrangement may not be able to perform typical eye exam tasks, it is essential to seek an ophthalmologist who has experience working with patients who have developmental and health conditions. These specialists are equipped to perform eye exams on non-verbal patients or those with additional health needs, using adapted techniques to accurately assess vision without relying on verbal responses or other traditional methods.
Nonverbal Eye Exam:
Treatment
Screening for Refractive Errors An ophthalmologist will assess strabismus through a comprehensive eye exam. Given that many individuals with a chromosome 8p rearrangement may not be able to perform typical eye exam tasks, it is essential to seek an ophthalmologist who has experience working with patients who have developmental and health conditions. These specialists are equipped to perform eye exams on non-verbal patients or those with additional health needs, using adapted techniques to accurately assess vision without relying on verbal responses or other traditional methods.
Nonverbal Eye Exam:
- Some individuals with a chromosome 8p rearrangement may engage in a matching game during the eye exam to help screen for refractive errors.
- Cycloplegic Retinoscopy is an effective test that requires no response from the patient. Special eye drops are used to dilate the pupils and relax the eye’s focusing mechanism. After about 30 minutes, the ophthalmologist uses a retinoscope to shine light into the eye and determine if vision correction is needed. This test allows for accurate vision assessment without requiring the patient’s direct feedback. Learn more about this type of exam on the Autism Speaks website.3
Treatment
- Eye Glasses may help to correct the misalignment of the eyes.
- Vision Therapy helps the eyes and brain work together more efficiently. These exercises target issues with eye movement, focusing, and coordination, reinforcing the connection between the eyes and the brain.
- Patching encourages the brain to engage both eyes, which may lead to improved alignment. The patch is placed over the stronger eye to stimulate the weaker one.
- Eye Muscle Surgery can adjust the length or position of the eye muscles to help align the eyes. However, individuals who undergo this procedure may also need vision therapy afterward to improve eye coordination and prevent future misalignment.4
- Boston Children’s Hospital. Strabismus and Amblyopia: Conditions.
https://www.childrenshospital.org/conditions/strabismus-and-amblyopia - Okur, Volkan, Chung, Wendy et al. “Clinical and Genomic Characterization of 8p Cytogenomic Disorders.” Genetics in Medicine,
https://project8p.org/wp-content/uploads/2023/08/s41436-021-01270-2.pdf - Davitt, Bradley, M.D. Nonverbal, Autistic and in Need of Glasses. Autism Speaks,
https://www.autismspeaks.org/expert-opinion/nonverbal-autistic-glasses - American Optometric Association. Strabismus: Eye and Vision Conditions.
https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/strabismus
Understanding Strabismus
8p Hero Insights
Management and Care Recommendations
Resources
Understanding Strabismus
Strabismus is a common eye condition in children, affecting about 2 to 4 percent of the general population.
Strabismus can cause one or both eyes to misalign:
- Esotropia occurs when the eye(s) turn inward
- Exotropia occurs when the eye(s) turn outward
- Hypertropia occurs when the eye(s) turn upward
- Hypotropiaoccurs when the eye(s) turn downward
8p Hero Insights
Project 8p Foundation Affiliated Research on Chromosome 8p Disorders
While the exact prevalence of Strabismus in individuals with chromosome 8p rearrangements is not well established, it is recognized as a common symptom. Research provides a clearer picture of the prevalence range, although results can vary based on the size and characteristics of the populations studied.
- A 2019 study, Clinical and genomic characterization of 8p cytogenomic disorder reported 8% of the participating patients reported Diarrhea.
Management and Care Recommendations
Ophthalmologic Evaluations:
Annual ophthalmologic evaluations are recommended for individuals with a chromosome 8p rearrangement to monitor and manage potential vision issues.
Screening for Refractive Errors
An ophthalmologist will assess refractive errors through a comprehensive eye exam.
Given that many individuals with a chromosome 8p rearrangement may not be able to perform typical eye exam tasks, it is essential to seek an ophthalmologist who has experience working with patients who have developmental and health conditions. These specialists are equipped to perform eye exams on non-verbal patients or those with additional health needs, using adapted techniques to accurately assess vision without relying on verbal responses or other traditional methods.
Nonverbal Eye Exam:
- Some individuals with a chromosome 8p rearrangement may engage in a matching game during the eye exam to help screen for refractive errors.
- Cycloplegic Retinoscopy is an effective test that requires no response from the patient. Special eye drops are used to dilate the pupils and relax the eye’s focusing mechanism. After about 30 minutes, the ophthalmologist uses a retinoscope to shine light into the eye and determine if vision correction is needed. This test allows for accurate vision assessment without requiring the patient’s direct feedback. Learn more about this type of exam on the Autism Speaks website.
- Eye Glasses may help to correct the misalignment of the eyes.
- Vision Therapy helps the eyes and brain work together more efficiently. These exercises target issues with eye movement, focusing, and coordination, reinforcing the connection between the eyes and the brain.
- Patching encourages the brain to engage both eyes, which may lead to improved alignment. The patch is placed over the stronger eye to stimulate the weaker one.
- Eye Muscle Surgery can adjust the length or position of the eye muscles to help align the eyes. However, individuals who undergo this procedure may also need vision therapy afterward to improve eye coordination and prevent future misalignment.
Resources
Boston Children’s Hospital. Strabismus and Amblyopia: Conditions.
https://www.childrenshospital.org/conditions/strabismus-and-amblyopia
Okur, Volkan, Chung, Wendy et al. “Clinical and Genomic Characterization of 8p Cytogenomic Disorders.” Genetics in Medicine,
https://project8p.org/wp-content/uploads/2023/08/s41436-021-01270-2.pdf
Davitt, Bradley, M.D. Nonverbal, Autistic and in Need of Glasses. Autism Speaks,
https://www.autismspeaks.org/expert-opinion/nonverbal-autistic-glasses
American Optometric Association. Strabismus: Eye and Vision Conditions.
https://www.aoa.org/healthy-eyes/eye-and-vision-conditions/strabismus
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This visualization is powered by research sponsored by Project 8p and survey data collected from the Chromosome 8p Registry, representing insights from a total of 120 8p heroes. It is part of the soon-to-launch Insights Portal, designed to offer advanced tools for data analysis, access, and visualizations, accelerating research and discovery for chromosome 8p disorders.
