Vision Screening in Children – Research Findings

Reference

/ Findings
Williams W R , Latif A H A, Hannington L and Watkins D R (2005) ‘Hyperopia and educational attainment in a primary school cohort’ Archives of Disease in Childhood 2005; 90: 150 – 153
[Also referred to briefly in British Journal of Ophthalmology, May 1, 2005; 89 (50: 542) / Local community paediatric service in South Wales screened just under 1300 children aged 8 with a standard vision screening protocol changed to include a fogging test for long sight.
SATs scores in reading and writing English and progress in the national curriculum in English, maths and science were significantly lower for the children…who were the most long sighted (>+3D for both eyes or >=1.25 for best eye) than for those who were less affected (<=+3D)…
13% of the total cohort had been referred to an optometrist after failing a test for long sight, and half of them needed glasses or a referral to an educational psychologist, or both.
Conclusions: the results of this study provide further evidence for a link between hyperopia and impaired literacy standards in children.
Note that screening for long sight is not performed in most schools.
Kiely P M, Crewther S G and Crewther D P (2001) ‘Is there an association between functional vision and learning to read?’ Clinical and Experimental Optometry, 84, 6, November 2001, 346 - 353
(See also ‘Letter to the editor: Vision and learning to read’ Clinical and Experimental Optometry, 85, 4, July 2002, 260 - 262. This contains response from the authors to letters concerning their original article.) / 284 Australian school children aged between 5.6 and 16 years (mean age 9.9 + 1.8 years) ‘received a vision screening emphasising binocular anomalies associated with discomfort at near (distance and near visual acuity, distance vision challenged with binocular +1D lenses, near heterophoria, near point of convergence, stereopsis and accomodative facility). Non-verbal mentation age and reading accuracy were assessed. One hundred and six children performed a computerised task of motion coherence detection. Children were classified as normal readers (n = 195), children with dyslexia (n = 49) or learning disabled children (n = 40) based on their mentation age and their reading age.
Results: There were no statistically significant differences or correlations between visual parameters and reading performance…
Discussion: The lack of association between ophthalmic parameters and poor reading ability supports the view of the Committee on Children with Disabilities. However, 39 per cent of the children might be expected to experience difficulty ‘reading to learn’ as suggested by the American Academy of Optometry, as they showed anomalies associated with visual discomfort with prolonged reading…Accommodative facility testing remained the most useful predictor of potential visual discomfort.’ (p346)
This paper reports findings from a larger study that is testing theories that relate ‘M-pathway visual functional deficits to dyslexia. The authors point out that although they found very little statistically significant correlation between reading ability and learning to read, they did find evidence that:
‘some children, while not having difficulty learning to read because of a vision problem, could be expected to have difficulty ‘reading to learn’ as a result of visual anomalies leading to visual discomfort with prolonged reading. This was particularly evident for the children with dyslexia where 23 of the 49 children (47 per cent compared to 35 per cent of normal readers) were referred for full ocular examinations…’ (p351) Although these results were not statistically significant, in their response to letters about this paper, the authors state:
‘What we expected to be of particular interest to clinicians was the trend indicating that children who were poor readers were also more likely to exhibit low findings on a test of accommodative facility. This supports the anecdotal observation that if it is uncomfortable to read, then visual discomfort with reading is unlikely to be the recipe for persistence on the child’s part, either as a means to improve reading or to cultivate reading as an enjoyable pastime.’ (p 261)
Junghans B, Kiely P M, Crewther D P and Crewther S G (2002) ‘Referral rates for a functional vision screening among a large cosmopolitan sample of Australian children’ Ophthalmic and Physiological Optics, 2002 Jan; 22 (1), 10 – 25
See also La Trobe university media release on this study: / Abstract
‘The aim of this study was to investigate the incidence of functional vision problems in a large unselected cosmopolitan population of primary school-age children and to investigate whether constant clinical criteria for functional vision problems would be implemented by the practitioners involved in the screening. Refractive errors, near point of convergence, stereopsis, strabismus, heterophoria and accommodative facility were assessed for 2697 children (3-12 years) of varying racial backgrounds living in Australia…Twenty per cent of the children were referred for further assessment…Post-hoc analysis of the record cards seeking the reason for further assessment indicates that referrals appear to have been based on clinical intuition rather than on a set number of borderline or unsatisfactory results.’
A media release from La Trobe university, at which Dr Sheila Crewther and Dr Patricia Kiely are based, quotes Dr Crewther as saying:
‘…despite school medical examinations, two thirds of vision problems go undetected, resulting in children under performing at school. “The problem is not that they cannot read what is on the blackboard but how long they can continue doing close-up tasks such as reading or writing or working on a computer. They become tired much more quickly than children with normal sight when performing such tasks and this causes them to ‘switch off’ and do something else,’ Dr Crewther said.’
Pattison B and Plymat K (2001) ‘Vision screening of school children: Should it be continued?’ Contemporary Nurse, 10 (3-4), June 2001, 163 – 171 (abstract from: / Abstract
‘Vision screening of all children at school entry has been a traditional practice for many years. Recently, decisions have been made to discontinue screening and to rely on parent and teacher referral methods instead. A review of the literature suggested that parent and teacher referral methods of screening were less than satisfactory, and that professional screening of all children at school entry age should be continued.’
I realise that this refers to school entry, but it does suggest that parents and teachers cannot be relied upon always to pick up a child’s sight problem.
With reference to the above, research in America suggests that factors such as ethnicity and economic status affect whether or not a child has their sight tested or wears spectacles. The research is summarised in a 2 March 2004 press release on and relates to four studies, which can be found in four different journals. These are: Pediatrics, March 1, 2004, Vol 113, No 3; Optometry and Visual Sciences, Jan 2004, Vol 81, No 1, pp 7-10; American Journal of Preventive Medicine, Feb 2004, Vol 26, No 2, pp 141-146; and Ambulatory Pediatrics, Sept-Oct 2003, Vol 2, No 5, pp 270 - 274.
The findings are seen to provide support for school-based screening programmes. As there are major differences between the UK and USA in that children in the UK are entitled to free eye tests and a voucher towards the cost of spectacles, whereas in the US parents need to pay (and insurance status was a significant factor) citing this type of US study needs to be done with great caution. However, it does highlight a point that might be worth making when putting forward the argument for sight tests at school. This is that children from disadvantaged backgrounds and from some ethnic minority backgrounds may be less likely to have parents who would take them to an optician to have their sight tested. I would suggest that this may apply for example, to children whose parents speak little or no English. A study by Mark Scase, presented as a poster at the Vision 2005 conference: ‘Visual impairment in ethnic minorities in the UK’ concludes: ‘…low levels of registration and apparent under utilisation of preventive, rehabilitation and support services by Black and minority ethnic groups should be studied.’

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