An Introduction to Cerebral Visual Impairment
Professor Gordon Dutton
Questions 1-5 - Assessment tools, Conditions associated with CVI (including foetal drug and alcohol syndrome), Strategies for children with those conditions
Slide text:
Questions
1. What is functional vision?
Vision used in day to day living
and
How to work with those students who have learning difficulties and a normal visual assessment cannot be completed
(next question)
Questions
2. What assessment tools are available for children with CVI and additional disabilities
Detailed history taking from parents
Refraction - near and distance
Careful observation of visual behaviours
Preferential looking methods & Vision evoked potentials that measure acuity and contrast
Child’s age |
Maximum eye contact distance |
Approximate Snellen Acuity |
Teller Acuity (cycles/degree) |
1-2 days |
0.3 |
6/540 |
0.33 |
2 weeks |
0.75 |
6/180 |
1 |
6 weeks |
1.15 |
6/90 |
2 |
3 months |
1.5 |
6/60 |
3 |
4 months |
1.75 |
6/45 |
4 |
6 months |
2.00 |
6/36 |
5 |
18 months |
3.00 |
6/18 |
10 |
8 years |
6.00 |
6/6 |
30 |
Eye contact distance as a way to estimate acuity
Questions
3. Are children with Foetal drug and alcohol syndrome at increased risk of CVI?
Yes - especially those born prematurely or with a very low birth weight
Features emerge as child develops
Questions
3. Is CVI found in children with medical conditions other than cerebral Palsy?
Head injury
Lack of blood supply (ischaemic encephalopathy - or very early stroke),
Lack of oxygen (respiratory or cardiac problems)
Infection (meningitis/encephalitis)
Arteriovenous malformation bleeds
Tumours
Prematurity
Structural disorders at birth (eg hydrocephalus)
Metabolic disorders (eg MELAS syndrome and leuko-encephalopathies)
Toxicity (drugs during pregnancy)
4. Is there any link or evidence that children diagnosed with Foetal drug and alcohol syndrome have an increased risk of CVI
Yes - issues emerging when aged about 3-5
Questions
5. Can you outline useful strategies for better understanding and communicating with them.
Use a tent to find out if the child has profound (masked) Balint Syndrome (BJVI Suzanne Little and Dutton)
Slow sounds and sights to match perception
Find and work within these limits