University of Edinburgh

Issues and Strategies for Visually Impaired Learners

Tuesday 7 March 2006

The Profile of Scottish Children with Visual Impairment

John Ravenscroft

With thanks to
Dr Andrew Blaikie
Professor Gordon Dutton
Marianna Buultjens
The Visual Impairment Scotland Research Group

VI Years

Childhood visual impairment has far reaching effects throughout life.

The Concept of VI Years

It can impact upon a child’s development, education, employment and social prospects. It can also lead to wide ranging effects upon the immediate family. Beyond the child and family.

Visual impairment creates financial implications for society, the provision of education, social and health services

(Rahi et al, 1999,Frick and Foster, 2003, Ho and Schwab, 2001.)

Children with visual impairment require an integrated and tailored service provision that involves health, education, social work, and voluntary organisations.

The Education (Additional Support for Learning) (Scotland) Act 2004

Accurate current data of the numbers, causes and level of visual impairment, and additional disabilities are required to plan and develop such a service.

To profile children we need to know

  • Number
  • Location
  • Age
  • Level of visual function
  • Level of visual field
  • Additional disabilities
  • Current service provision

But in Scotland . . .

In Scotland the Social Services hold a blind and partial sight register.

Several adult studies have however highlighted the incompleteness of the official blind and partial sight register.

(Bunce et al, 1998b,Evans and Wormald, 1993,Robinson et al, 1994b, Wormald and Evans, 1994.)

In Scandinavia
This is in contrast to Scandinavia where a collaborative effort over the past several decades has led to an extensive literature on the epidemiology of childhood visual impairment offering useful information to health, education and social service planners.

(Rudanko et al, 1993,Riise et al, 1992a,Hansen et al, 1992,Rosenberg et al, 1992, Riise et al, 1992b)

This information can also aid research into prevention, diagnosis and treatment of conditions causing visual impairment.

Aims of VI Scotland
The primary purpose of this work was to develop a new method of notification for children with visual impairment in Scotland and to describe the information collected.

This type of approach could be further applied across the range of low incidence childhood disabilities.


Not Quite

  • VIS is a unique model of notification
  • Parent Led System Notification
  • Empowers parents and children
  • Provides Direct and Relevant Services to Parents and Children
  • Parents & Children Specific Website
  • Children their own club (see certificate)
  • Parent Network Support Community
  • Medical Information Documents

The Eye and Normal Development

eye and normal development

Normal visual development

  • Newborn 6/240
  • 2-3 mths 6/180 – 6/90
  • 6 mths 6/60 – 6/24
  • 12 mths 6/18 – 6/12
  • 18 mths 6/9
  • 24 mths 6/6 singles
  • 4 yrs 6/6 test type

visual acuity

What is Significant Visual Impairment

  • A best corrected binocular visual acuity equal to or worse than 6/18 (or equivalent) or;
  • Any form of visual field loss or;
  • An eye movement disorder which affects visual function or;
  • Any form of cognitive visual due to disorders of the parts of the brain subserving visual function.

Professionals & Notification

  • Most notifications come from clinics* with parents
  • Parents complete forms in clinic
  • Average time 3 mins

*Ophthalmologist's clinic
*Orthoptist's clinic
*Community Paediatrician's clinic

Visual Impairment in Scotland

  • Total number of children notified 700
  • Total number significant visual Impairment = 370
  • Total number = NSVI =330

division of significant to non-significant vi notifications


division of notifications by ad

type of additional disabilities

percentage of children with additional disabilities

VIS compared their data to Sweden which has a near 100% capture and results show a very near match – so suggests data is valid.

This is a graph of children with additional disabilities.

Most have at least two additional disabilities over and above VI.

ethnic groups


location of notifications

site of visual impairment

eye,optic nerve and brain

ACUITY: The NORDSYN Classification System


Nordysn and Logmar

O 0 to 0.48 (non inclu)
A 0.48 to 1.00 (non inclu)
B 1.00 to 1.78 (non inclu)

visual acuity

visual acuity

Primary Diagnosis

  • For all notifications
  • 66 different conditions names by the child's health professional
  • CVI
  • Albinism

primary diagnosis


Aetiological classification

This study categorised the time of acquiring the cause of childhood visual impairment into three major periods:

  • Prenatal, before birth including both genetic and intrauterine (in the womb) causes;
  • Perinatal & neonatal, at the time of birth and within the first 28 days of life;
  • Postnatal, during childhood, after the first 28 days of life.


aetiology of childhood vi

Disorders acquired in the prenatal period were the most common).

The second most common is at and around the time of birth).

Prematurity and hypoxic/ischaemic damage are the two main causes of acquired visual impairment at this time.

It was uncommon to acquire a visually impairing condition during childhood.

Visual Field Loss

visua field loss

  • Lower Visual Field Loss most common;
  • Peripheral most common for significant VI.

Our data shows that practically all the lower visual field loss and the hemianopia comprises of cases of CVI.

With the lower field loss being PVL, or presumed PVL, or hydrocephalus.

registration by age


In Sweden
13.1 per 10,000 births in Sweden

In Denmark
Prevalence rate in Denmark 12.9 per 10,000 births

In Scotland
An estimated 12 per 10,000 births

However a one year capture of birth suggests

6 of every 10,000 children born in the UK each year become severely visually impaired or blind by their 16th birthday and probably a further 12 becoming visually impaired (worse than 6/18 or 0.5 to 1.0 Log MAR)*1.

Thus there are at least 4 newly visually impaired children each day in the UK and 2 per 1000 children in a given population at any time are visually impaired or blind*2 .

Rahi J, Cable N Severe visual impairment and blindness in children in the UK. Lancet 2003;362(9393):1359-1365.


This study has identified that using information as a mechanism of attracting notification of disability works well for children, families and service providers.

The information and support service has been well used raising awareness amongst parents and professionals generating notifications.

In total there have been over 2 million hits to the website and continue to increase every month.

To summarise

Policy makers and planners of integrated medical, educational and social services aiming to meet the needs of children with special needs, face the difficult task of delivering services based on information that may not describe the full scale or spectrum of children to be served.

This study, by linking a relevant and tailored user-driven information and support service to a broad base of notifying professionals (ophthalmologists, optometrists, orthoptists, paediatricians, teachers and social workers) has developed an inclusive system of notification of a low incidence childhood disability.

This type of approach is not confined to visual impairment and could be further applied across the range of childhood disabilities.