Children’s vision screening

Young boy with his right eye covered for occlusion therapyThis article has been written by the British and Irish Orthoptic Society (BIOS), Vision Screening Special Interest Group Steering Committee. 

What does vision screening detect and why is it needed?

“Amblyopia is a condition where the observer sees nothing and the patient sees very little.” (Von Graefe, 1888).

Reduced vision in young children is generally due to the presence of amblyopia (lazy eye). It is a developmental disorder in which there is reduced vision, despite wearing glasses. Typically, it affects one eye but it can affect both. As there are few signs and symptoms to observe, detection is very difficult for parents/carers. Having poor vision in one eye makes the child almost three times more likely to become blind (poor vision in both eyes) during their lifetime (Chua and Mitchell, 2004).  Current research examining the impact of children’s vision levels on their developing literacy as they start school indicates that reduced vision is associated with lower literacy achievement (Bruce et al, 2016). Early literacy is a key indicator of future educational attainment therefore population based screening is important to ensure equitable access for all children.

In 2013, following a major evidence review, the National Screening Committee (NSC) recommended that Orthoptic-led screening for visual impairment should be offered for all children aged 4 to 5 years (NSC, 2013). Despite the NSC recommendation, children’s vision screening is still not consistently commissioned throughout England and, as a result, there is a risk that treatable vision conditions could be missed. In Scotland Orthoptists have a government mandate to deliver the screening. In Wales Orthoptists are working with the Welsh Government for Vision Screener-delivered testing and have an agreed all-Wales Vision Screening Care Pathway. In the Republic of Ireland vision screening is delivered as part of the national core child health programme by school nurses trained by Orthoptists. In Northern Ireland there is regional vision screening in schools with all 4-5 year olds a having a vision test by nurses trained by Orthoptists.

One of the more recent barriers to provision in England has been a shift in commissioning, with responsibility for children’s vision screening services moving to local authorities in October 2015. The ability to deliver on the NSC guidelines is being prevented by the lack of clarity in commissioning responsibility and knowledge of national guidance. There is evidence that this has led to a number of services being decommissioned, as shown by the data collected from the Clinical Council for Eye Health Commissioning (CCEHC), Freedom of Information request reported in February 2016.

Why is it important to treat amblyopia and how is it treated?

The main aim of vision screening is to detect amblyopia which is a treatable vision defect occurring in approximately 3% of children (Williams et al, 2008). Amblyopia is for most children an asymptomatic condition treated using occlusion therapy, where the better eye is temporarily blurred or covered. The age of detection and treatment, before the age of eight years, is vital for a good vision outcome. Orthoptists specialise in paediatric vision testing and treatment of amblyopia working together with Ophthalmologists and Optometrists to provide treatment for children referred from vision screening.

How does vision screening differ from relying on parents taking children to an optometrist?

Vision screening should be systematically offered to all children in the local population aged 4-5 years, ensuring the ‘at risk’ and vulnerable children in the population are reached. This means that every child will be given the opportunity to have their vision tested without the onus being put on to parents to remember to take their children for an assessment. This is essential to those who do not seek advice or do not think they are at risk, and show no signs or symptoms of the condition.

The age of screening is standardised and allows a vision test to be carried out that is accurate enough to detect real problems whilst minimising the number of children referred for further testing unnecessarily. Vision screening before the age of four years yields high false positives as vision is not fully developed, hence normative values for visual acuity are wider.

In a screening programme, results are recorded on the child health information system. This allows for a checking mechanism to make sure all children have been screened and is particularly important for those in vulnerable or ‘at risk’ categories. Referral pathways and data collection associated with vision screening enables follow up on any children who do not attend subsequent appointments. This allows for communication with GPs and other health and education professionals in children where there is a cause for concern. The use of vision screening programmes for all children ensures appropriate, evidence-based service delivery with auditing of results necessary for NHS governance and quality assurance systems. 

A parent’s view of vision screening

Grianne O’Brien’s daughter, Jessica, was seen and referred following vision screening at the age of five in her school in North Tyneside. She said ‘I hadn’t noticed anything wrong with Jessica’s eyes. She had never complained of problems, so it was a shock when we received the letter following her screening to say she had been found to have reduced vision. We received a letter from the screening with the result and an appointment, to be seen at the Children’s Eye Clinic. Jessica didn’t need glasses. She was offered the choice of drops or patches to improve the vision in her left eye. She chose patches and wore them well at school. This has improved her vision and within a year both eyes are now at the same level. Vision screening has been so valuable in our case. If Jessica hadn’t had the check and the treatment, it would be too late to improve her vision’.

What is the strategy to promote equitable vision screening at age 4-5 years?

In April 2016, a Vision Screening Advisory Group was set up by Public Health England to produce and disseminate materials to support the implementation of consistent, high quality vision screening services. This group brings together experts from Public Health England, professional organisations (representing Orthoptists, Optometrists and Ophthalmologists), academics, practitioners, directors of public health and the Local Government Association. The group will be producing high quality, locally relevant, evidence-based guidance and tools for commissioning and delivery of vision screening programmes. These will be sent out to key stakeholders in the early part of 2017 with the hope that this information can be used to ensure all children have access to good quality vision screening and have chance to achieve the best vision potential they can.

References

Bruce A, Fairley L, Chambers B, Wright J, Sheldon TA. Impact of visual acuity on developing literacy at age 4-5 years: a cohort-nested cross-sectional study. BMJ Open 2016;6:e010434 doi:10.1136/bmjopen-2015-010434

Chua B, Mitchell P. Consequences of amblyopia on education, occupation, and long term vision loss. British Journal of Ophthalmology 2004;88(9):September-1121.

National Screening Committee (2013). https://legacyscreening.phe.org.uk/vision-child

Public Health England (2016). https://phescreening.blog.gov.uk/2016/05/17/a-vision-for-vision-screening/

Public Health England (2016). https://phescreening.blog.gov.uk/2016/11/02/we-still-have-the-vision/

Von Graefe A. (1888) Archiv für klinische und experimentelle, 1888;34:1-2

Williams C, Northstone K, Howard M, Harvey I, Harrad RA, Sparrow JM. Prevalence and risk factors for common vision problems in children: data from the ALSPAC study. British Journal of Ophthalmology 2008 July;92(7):959-64.