Visual Impairment Scotland Research

Blind and Partial Sight Registration in Children

Blaikie AJ, Ravenscroft J, Buultjens M, Dutton GN, Visual Impairment Scotland Research Group

Royal College of Ophthalmologists Congress
Birmingham, May 2003

Purpose

It is well recognised that the official blind and partial sight registration system underestimates the real prevalence of visual impairment1,2,3,4,5,6,7 in the United Kingdom. The literature however refers almost exclusively8 to adult populations. The purpose of this study is to describe the registration rates and characteristics of a population of visually impaired children in Scotland.

Methods

The inclusive nation-wide childhood visual impairment database of Visual Impairment Scotland (VIS) was analysed for blind and partial sight registration rates and the relationship with visual function, eligibility, age, additional disabilities and anatomical site of impairment.

Results

Overall Blind and Partial Sight Registration Rates
333 children with ‘significant visual impairment’ (visual acuity worse than 6/18 and/or any visual field loss and/or cognitive visual dysfunction) were notified to VIS between March 21 2001 and September 21 2002.

Overall 198 of these children (59%) were reported to be registered either blind or partially sighted. 104 (31%) were registered blind and 94 (28%) partially sighted.

Visual Function Group
VIS employs a modified version of the NORDSYN visual function classification system (Table 1).

There were children registered blind or partially sighted in all visual function groups. There was a clear trend for a blind registeration in the poorer visual function groups (Figure 2). There was an opposite trend for partial sight registration.

Eligibility
The recommended criteria for registration as blind or partially sighted in Scotland, as described on the BP1 form (equivalent of BD8), includes a visual acuity of worse than 6/60 or ‘marked contraction of the fields’ regardless of visual acuity. Using these criteria 181 eligible and 152 ineligible children were identified.

Three quarters (75%) of the eligible and half (50%) of the ineligible children were registered.

Age Groups
There were no children under the age of 2 years (0/9) registered blind or partially sighted. The percentage of children registered partially sighted is least in the under 5 year old group (11%) and increases as children get older (40% in 11 to 15 year olds).

This is a strikingly different trend from the percentage of children registered blind which is similar in all three age groups.

Additional Disabilities & Anatomical Site
Less children with the brain (48%) as the primary anatomical site of impairment were registered compared to those with impairment due to the eye or optic nerve (70%). This was statistically significant (p=0.0001).

There was a trend (p=0.092) for less children with additional disabilities to be registered blind or partially sighted (55% or 105/190) compared to those with with no additional disabilities 65% (93/143).This is despite a trend for children with additional disabilities to have worse overall visual function.

Conclusions

By the recommended criteria there were many children eligible for registration but not (25%) and many who were not eligible for registration but who were (50%). It is clear that ophthalmologists are registering children with a wider range of visual disability than that described by the recommendations (which were originally developed for adults).

Children with ‘complex’ cerebral visual impairment (CVI) and additional disabilities were less likely to be registered compared to those with ‘simple’ ocular aetiology without additional disabilities.
This study therefore confirms that the blind and partial sight register is, as has been shown in adults, incomplete and biased to certain populations. It consequently does not identify all those that are in need and therefore cannot act as an effective tool to either plan service provision or perform visual impairment research.

It is recommended that broader forms of assessment and certification criteria should be developed that emphasise the challenges of assessing young children with CVI and their particular visual difficulties9,10,11. To make the system more attractive to children and their parents the use of the terms ‘blind’ and ‘partial sight’ should be replaced with a graded continuum of ‘visual impairment’ as recommended in the Certification & Registration Working Group Report12. We recommend development of multi-agency community-based vision teams13 to aid identification and assessment of children with visual impairment and improve communication and sharing of information amongst professionals to allow delivery of more coherent, prompt and focussed care packages.

References:
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2. Bruce IW, McKennell AC, Walker EC. Blind and partially sighted adults in Britain: the RNIB Survey. London: HMSO, 1991;1.
3. Wormald RPL, Wright LA, Courtney P, Beaumont B, Haines AP. Visual problems in the elderly population and implications for services. BMJ 1992;304:1226-1229
4. Evans JR, Wormald RP. Epidemiological function of BD8 certification. Eye 1993;7 ( Pt 1):172-9
5. Robinson R, Deutsch J, Jones HS, Youngson-Reilly S, Hamlin DM, Dhurjon L, Fielder AR. Unrecognised and unregistered visual impairment. Br J Ophthalmol. 1994 Oct;78(10):733-4
6. Bunce C, Evans J, Fraser S, Wormald R.BD8 certification of visually impaired people. Br J Ophthalmol 1998 Jan;82(1):72-6
7. King AJ, Reddy A, Thompson JR, Rosenthal AR. The rates of blindness and of partial sight registration in glaucoma patients. Eye. 2001 Oct;15(Pt 5):691.
8. Walker EC, Tobin MJ, McKennell AC. Blind and partially sighed children in Britain: the RNIB Survey. London: HMSO, 1992;2.
9. Dutton GN, Jacobson LK.Cerebral visual impairment in children. Semin Neonatol. 2001 Dec;6(6):477-85
10. Houliston MJ, Taguri AH, Dutton GN, Hajivassiliou C, Young DG. Evidence of cognitive visual problems in children with hydrocephalus: a structured clinical history-taking strategy. Developmental Medicine & Child Neurology 1999, 41: 298-306
11. Dutton GN. Cognitive vision, its disorders and differential diagnosis in adults and children: knowing where and what things are. Eye. 2003 Apr;17(3):289-304
12. Certification and Registration Working Group, Social Work Services for People with a Sensory Impairment, The Scottish Office: May 2001
13. A J Blaikie, M Campbell, G Coyle, E Lymburn, M Comerford, M Buultjens, GN Dutton Introduction of a multi-disciplinary community vision assessment team The 7th International Conference on Low Vision Activity and Participation July 2002, Göteborg, Sweden

John Ravenscroft
Manager
VI Scotland, SSC