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I.
The importance of vision habilitation in children
A. Epidemiology
1. Prevalence is low (visual impairment of those without additional
impairments; approximately 0.05%)
2. Visual impairment years are longer
3. Commonest causes of visual impairment in children
B. The impact of visual impairment on development
1. All areas of development are affected
2. It is a rehabilitation emergency
3. Early “habilitation” is essential
II. How children differ from adults
A. Active accommodation
1. Relative distance magnification
2. But close working distance
3. Accommodation decreases during childhood
4. Accommodation may be reduced compared to norms
B. Children do not complain of symptoms
C. Children have rapidly changing visual demands
III. 0-5 year olds (pre-school and kindergarten)
A. Children seldom seen in LV Clinics before 5-6 years – but assessment should start
earlier than this
B. Most disorders in this age group are congenital
C. Concerns of parents in pre-school years
1. What can my child see?
2. Will s/he be able to read/drive/ when older?
3. Will his/her vision get worse?
4. What can be done to help him/her use his/her vision better?
5. Will glasses help?
D. Functional assessment
1. Ability to fix and follow
2. Binocularity and assessment of nystagmus
a) Case study
3. VA, distance and near
a) Hierarchy of tests (detection, resolution, recognition)
4. Refraction
a) Retinoscopy
b) Use of cycloplegia
c) Subjective
5. Visual fields
6. Charts for Contrast sensitivity
7. Assessment of accommodation
E.
Management/Intervention
1. Information
a) In clinical and lay terms
b) Acuity reserves for children
c) Information on visual fields, lighting, positioning
2. Spectacle prescription
a) Full Rx, for optimum function
b) Lack of emmetropisation in LV
3. Tints
a) Those with normal colour vision
b) Achromatopsia or cone dystrophy
4. Lighting control
a) Blinds, drapes, dimmer switches
b) Hats
5. Low vision aids
a) Stand magnifiers
b) Telescopes
6. Vision stimulation
a)
b)
c)
d)
Definition
Children with severe VI
Lagging developmentally
Multiple-impairments
7. Visual perception training
a) Description
8. Orientation and mobility training
9. Safety glasses
10. Follow-up
IV. 6-10 year olds
A. Visual demands are changing
B. More cognitively demanding testing is possible
1. E.g. Colour vision by 5 years
C. Reading additions/microscopes
1. Consider even when near vision is good
2. Acceptable reading speeds in children
a) Age 8-9 60 wpm
b) Age 9-11 70 wpm
c) Higher ages 90wpm
3. Consider signs and symptoms
4. Steps to determining a reading add in children
a)
b)
c)
d)
e)
f)
g)
Identify goal or target print
Measure child’s near threshold
Calculate expected amplitude of accommodation
Calculate estimated add
Demonstrate add and re-measure near acuity
If not adequate, calculate change
Consider stand magnifiers
5. Telescopes
a) Hand-held or spectacle mounted options
6. Adaptations at school
a)
b)
c)
d)
Large print books
Black felt tips pens or roller ball pens
Copies of blackboard work from teacher
Child allowed to move up to blackboard
7. CCTVs and adapted computers
8. Additional time on tests/exams
9. Colour contrast
10. Sports
a) Why sports are important
b) Which sports to suggest
V. 11+ years
A. Less change in print size
B. More change in quantity of written work
C. Maybe new demands e.g. music, geography
D. Music
1. Choice of instrument
2. Reading music is a particular problem
a)
b)
c)
d)
Enlarged photocopies
Telemicroscope
Head borne videotelescopes
Memorisation
E.
Electronic devices
F.
Dealing with self conscious teens
References
Harper R (2004) “Low Vision assessment and management” in Paediatric Optometry Ed.
Harvey W, Gilmartin B. Butterworth_Heinemann, Edinburgh. P91-98.
Leat SJ, Shute R, Westall C (1999) Assessing Children’s Vision : A handbook.
The effects of visual impairment on development pp 29-33.
Children with low vision pp 359-369
Leat SJ, Mohr A. (2007) Accommodative response in pre-presbyopes with visual
impairment. Invest. Ophthalmol Vis Sci. 48(8):3888-96.
Leat, SJ (2008) Reduced accommodation in children and young people with low vision
– are there clinical implications? Proceedings of the 9th International Conference on Low
Vision, Vision 2008, Montreal, 117.1
Lovie-Kitchin JE, Bevan JD, Hein B. Reading performance in children with low vision. Clin Exp
Optom. 2001;84:148-154.