On Tuesday 15 March, 2022 we were delighted to welcome Minny Tang, Occupational Therapist at Ebenezer School & Home for the Visually Impaired, to host an online webinar on “Vision and development in children with special needs”.
The event was well attended with more than 40 people signing up online, indicating this is a topic of great interest for SNNHK members.
Established in 1897 and based in Pokfulam since 1912, Ebenezer offers a range of educational services (for preschool and school age children) and support services for young adults as well as a care home for the elderly with visual impairments.
The vision development timeline: how we see
As background, Minny explained how the eye works and how we see, and how this develops as we mature. Newborn babies can only see in black and white and shades of grey, and their eyes cannot focus well.
Newborns have an estimated visual acuity (meaning the clarity or sharpness of vision) of between 20/200 and 20/400. They prefer human faces to other forms of stimulation. Between 1 and 3 months old, babies can follow moving objects and by 7-11 months, babies’ depth perception emerges, and they are aware of differences in height. From 12-18 months they develop an interest in pictures and their visual acuity is 20/20. Between 18 months and 3 years old, their vision is fully developed.
Cortical/ Cerebral Visual Impairment vs Ocular Visual Impairment
Minny explained that there is a difference between Cortical or Cerebral Visual Impairment (CVI) which is caused by a problem in the way the brain processes information from the eyes, and Ocular Visual Impairment (OVI) which is caused by a problem with the actual eyes. Understanding what type of visual impairment your child has is very important in ensuring they receive the proper treatment and care.
Parents need to know whom to consult, whether this is an ophthalmologist, optometrist, or other specialist, and your therapist and/ or social workers may be able to support.
To diagnose CVI, several “rules of exclusion” apply: a regular eye exam can’t explain why the child cannot see; there may be a history of brain damage, and there is a presence of various visual-related behaviours.
CVI can be caused by a number of factors including genetic disorders, premature birth, hypoxia or hydrocephalus, head injury, infantile spasm, meningitis, and others.
What are the symptoms of CVI?
Children with CVI have problems responding to the things they see. They prefer to look at things that are moving and sometimes prefer to look out of the side of their eye (peripheral vision). They sometimes stare at lights, such as lamps or ceiling lights, or could have a strong colour preference. Minny showed some videos of examples of this kind of vision impairment in young children.
Minny listed three key tips for dealing with children with special visual needs, which include to inspire trust; to learn about the “who” (ie. focus on the child’s personality rather than their disability); and to focus on “training in play”. It is also important to distinguish between visual development and the child’s development in other areas such as gross motor and fine motor skills, social skills, communication and language development.
Minny advised on several environmental adaptations parents can use to draw their child’s attention, such as different reflective surfaces, playing with contrasting colour toys, and black and white patterns.
She recommended some books including Babies with CVI by Anne Cormiskey, Little Bear Sees by Andrei Tallent, Aubri Tallent and Fredy Bush, and Vision and the Brain by Amanda Hall Lueck and Gordon Dutton. The full list of recommended books on CVI can be found on the Books of Interest - Cerebral Visual Impairment section of the SNNHK website.
Question and Answer session
Some of the questions asked by our members and answered by Minny included:
Q. Is a referral required for a child to enrol in the Ebenezer Early Intervention Program?
A. Ebenezer takes referrals from the public system, and if parents have any difficulty they can call directly.
Q. As a specialist, how do you tell how well a child can see if they cannot explain themselves? For example, if they have multiple severe disabilities?
A. We conduct functional assessment by closely observing behaviour then compare our findings against what is considered to be a standard timeframe for “normal” development.
Q. Is there a network of optometrists that test eye movement specifically?
A. There are some specialists including developmental optometrists, the Chinese University of Hong Kong Eye Centre, the Optometry Clinic at PolyU and the Hong Kong Society for the Blind can advise.
Q. Is severe near-sightedness considered visual impairment?
A. Near-sightedness is correctable and is therefore not considered to be ocular visual impairment. The child will only be diagnosed with visual impairment if his/her visual acuity still meets visual impairment criteria after the use of corrective lenses.
Q. My child has difficulty with depth perception. Are there any exercises we can do to follow up?
A. One of the factors affecting depth perception is binocular vision and if there is a problem it means the eyes are not working together as a unit. You can do exercises such as moving a pen in and out and asking your child to focus on the pen. Brain processing may also affect depth perception.
Q. Does lack of eye contact mean the child has visual impairment?
A. lack of eye contact does not necessarily mean the child has visual impairment as it can also be a symptom of autism spectrum disorder. It is always better to get the child checked out by a medical professional.
Q. My child prefers faces on books rather than actual human faces. How can I get him/her to look at me?
A. Faces on books are usually much simpler and easier for children to process. Parents and caregivers can try wearing mask to reduce the amount of details. They may also try to make facial features more distinguished by wearing glasses with sharp-coloured rim or bright red lipstick.
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