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Down syndrome: the mysterious benefits of bifocal glasses

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What did the project achieve?

“This work has helped to improve understanding of the visual abilities and difficulties faced by children with Down syndrome – raising questions about the materials they are provided in school and how they are taught to scan pictures to take in information,” says Dr Maggie Woodhouse of Cardiff University. “We are now able to make some practical suggestions to help support these children better in school.”

Around 750 babies with Down syndrome are born each year in the UK.1 Many children and young people with the condition have problems with their eyesight as well as learning disabilities. If a child’s vision problems are not recognised and corrected, there’s a danger that people might think their learning disability is more severe than it is – that can lead to unnecessary effects on the child’s learning.

The team recorded eye movements of 97 children – including 64 with Down syndrome – while they scanned a picture containing either four or six images, looking for a particular image they had been asked for.

We initially set out to understand why children with Down syndrome who struggle to focus on things nearby appear to benefit from wearing bifocal glasses,” says Dr Woodhouse. “But unexpectedly, the way these children scan pictures and the control of their eye movements while looking at a single image turned out to be more relevant than the effect of the bifocals.”

The team identified key differences in search strategies and abilities to ‘fix’ on specific objects during the task between the children with Down syndrome and typically developing children.

“Children with Down syndrome take much longer to find the chosen image because they scan the entire picture so quickly that their eyes do not rest on each image in turn for as long as typical children,” says Dr Woodhouse. “So it might be they are not identifying each picture immediately to ‘accept’ or ‘reject’ each item as they scan them.”

The researchers also found evidence that children with Down syndrome have more unstable eye movements compared to typical children.

“When their eyes are relatively still, fixating on an object, children with Down syndrome make more and larger random movements than typical children do,” says Dr Woodhouse, “But we have not yet established if this is due to poorer eye movement control – or difficulties with their attention.”

The results from the Action study enabled the team to carry out further research to look for cerebral visual impairment (CVI) in children with Down syndrome – a condition that affects the ability of the brain to make sense of visual information. The study found that almost four out of ten of children with Down syndrome were suspected to have this condition.2

“A major symptom of CVI is being unable to cope with crowded spaces or complex scenes, which adds to their problems with eye movements,” says Dr Woodhouse. “Many children also lack depth perception – which affects their ability to perceive the world in three dimensions and judge the distance of objects – so they may also struggle with navigating steps and uneven flooring.”

Children attending the researchers’ clinics are already benefitting from the Action-funded work. Parents now have a greater understanding of their children’s visual scanning abilities and limitations are being advised to present tasks one at a time, and to avoid distractions, to allow children to hold their gaze on the appropriate part of the task.

“Complex visual scenes provided for children with Down syndrome could be simplified with opaque masks to make it easier for them to work with,” says Dr Woodhouse. “We would also suggest that school materials for these children are simplified, avoiding any crowding – and that they are given additional time for any tasks that require more complex scanning.”

Dr Woodhouse expects the results of both the eye moment and CVI studies, will further influence clinical practice in the UK and beyond. Their next goal is to develop diagnostic guidelines or instruments appropriate for children with Down syndrome and other learning disabilities, which will ultimately help them reach their full potential.

[1] The Down Syndrome Medical Interest Group https://www.dsmig.org.uk/information-resources/by-topic/demography/ [website accessed 5 August 2021]

This research was completed on

Around 750 babies with Down syndrome are born each year in the UK.1 Many go on to have problems with their near vision, meaning they need glasses.2 Parents and teachers of some children have noticed they seem to do much better with bifocals than expected, and the children themselves say they prefer bifocals. Dr Maggie Woodhouse, of Cardiff University is investigating why. Her findings could help ensure children get the best glasses for them, so they can see the world as clearly as possible. Important knock-on effects could include better learning, improving children’s prospects in life.

Supported by generous grants from The Garfield Weston Foundation and the Tom and Sheila Springer Charity.


How are babies’ lives affected now?

Estimates suggest around 60,000 people have Down syndrome in the UK, 7 million worldwide.1,3 From an early age, vision problems are common.

“Many children with Down syndrome have vision problems,” says Dr Woodhouse. “The children also have a learning disability. If vision problems are not recognised and corrected, there’s a danger that people might think a child’s learning disability is more severe than it is. People might then have lower expectations of the child than they should have, meaning the child’s learning is unnecessarily affected.”

“Children with Down syndrome who struggle to focus on things nearby seem to do really well with bifocals,” continues Dr Woodhouse. “They see more clearly and do better school work. They also seem to get much better at exploring their world than we’d expect by simply improving their near vision and we don’t understand why.”

This lack of understanding could mean some children are missing out on the potential benefits of bifocals simply because they’re not being given them.

How could this research help?

“We hope to discover more about how bifocals improve the vision of children with Down syndrome and their ability to explore the world around them,” says Dr Woodhouse.

The researchers are studying how children scan a scene and pick out objects of interest – by looking for something in particular among many different words and pictures on the page of a book, for example. Parents of children with Down syndrome have said their children struggle with this type of activity and that bifocals seem to help.

“Our work could lead to better ways to predict which children will benefit from bifocals, along with new prescribing guidelines for specialists in eye clinics, who don’t all know how to prescribe bifocals for children,” adds Dr Woodhouse

“Better vision could improve both children’s learning and their quality of life – perhaps giving them a better chance of living independently, for example, or finding suitable employment when they grow up,” says Dr Woodhouse.


1. Down’s Syndrome Association. General FAQs. http://www.downs-syndrome.org.uk/about-downs-syndrome/general/ Website accessed 18 December 2014.

2. Stewart RE et al. In focus: the use of bifocal spectacles with children with Down's syndrome. Ophthalmic Physiol Opt 2005; 25(6): 514-22.

3. Down Syndrome International. Press Release: Down Syndrome International announces recipients of World Down Syndrome Day Awards - Down Syndrome International - 14 March 2014. http://www.ds-int.org/news/down-syndrome-international-announces-recipie... Website accessed 18 December 2014.






Project Leader Dr J Margaret Woodhouse OBE PhD BSc FSMC
Project Team Professor Jonathan T Erichsen BA DPhilDr Julie-Anne Little PhD BSc MCOptom FHEAMs Cathy Williams PhD FRCOphthMr Patrick Watts MBBS MS FRCS FRCOphthProfessor Kathryn Saunders PhD BSc FCOptom FHEA
Project Location School of Optometry & Vision Sciences, Cardiff University
Project Location Other School of Biomedical Sciences, University of UlsterCentre for Child and Adolescent Health, School of Social and Community Medicine, University of BristolDepartment of Ophthalmology, University Hospital of Wales
Project duration 3 years
Date awarded 21 November 2014
Project start date 1 July 2015
Project end date 28 February 2019
Grant amount £169,053
Grant code GN2338


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