Visual impairment and prematurity
Visual impairment in children born prematurely is most commonly associated with a condition called Retinopathy of Prematurity (ROP). When a baby is born prematurely the blood vessels of the retina will not be fully developed. The reasons are not fully understood but an unknown factor triggers the blood vessels to grow abnormally, forming scar tissue. In the extreme this can damage or detach the retina and lead to visual impairment.
ROP affects about 65 per cent of babies weighing less than 1250g (2lb 12oz) at birth. It is usually very mild and settles on its own without any treatment but a small number of babies, generally the smallest and most premature, will require treatment.
The first screening of a baby’s vision will be done between four and six weeks of age. Some babies will need one examination but most will need at least two.
If ROP is identified but is mild there will be a follow up examination one to two weeks later. If the follow up shows that the ROP has not become worse then it will settle on its own. If more severe ROP is identified at the first examination then there will be an earlier re-examination, usually in a week. In a small number of cases the ROP may be severe enough to require treatment.
The most effective way to treat severe Retinopathy of Prematurity is laser treatment but may occasionally involve freezing of the retina instead. Some studies have shown that early treatment leaves 50%-80% of treated babies with good or very good eyesight. For most babies one treatment is effective but there can occasionally be a need for a second treatment around two to three weeks later.
Squint (strabismus) and short-sightedness (myopia)
Babies with severe ROP, even if treatment is not required, are more likely to develop short-sightedness or a squint as they get older. In these instances the baby will most likely need to wear glasses later on.
Cerebral (sometimes called Cortical) Visual Impairment (CVI)
CVI is caused by damage within the brain and is most commonly associated in prematurity with cerebral palsy. The damage prevents the child from correctly receiving or interpreting information from their eyes. The difficulties a child experiences will depend on the degree and location of damage.
A child with CVI may have difficulties:
- knowing precisely where things are in three dimensions. This can make it difficult for the child to move around safely e.g. using stairs.
- seeing several different things at the same time or isolating one item amongst many e.g. finding a toy on a patterned carpet or seeing something that is pointed out in the distance amongst other things.
- recognising familiar faces, objects and places.
- with their eyes becoming 'tired' more quickly than others. This means that their ability to see can vary from one time to another.
- focusing when looking at a close object.
- making fast eye movements to track moving objects.
- with visual field loss, meaning that parts of what somebody without visual impairments can see may be missing or appear blurred.
CVI tends not to worsen and some children’s use of vision significantly improves over a period of time. However, even when improvement occurs vision will usually remain impaired to some extent.
Treatment of CVI
There are currently no medical treatments for CVI. Instead efforts should be focused on managing the condition through the use of spectacles, contact lenses and other low vision aids.
Early interventionfor visually impaired children should begin as early as possible in a positive emotional setting that enhances the child’s motivation and relationship with parents and carers. This will ensure significantly improved outcomes for the child.View more information about early intervention for children with visual impairments, other guidance and sign posting for parents.
Some children have hearing or vision impairments, or both, as a result of their prematurity.
Sense's Children's Specialist Services
Sense's Children's Specialist Services are a team of specialist advisory teachers, children’s therapists, and Children and Family Support Workers. The team provides advice and information to multi-sensory-impaired children and young people, to their families or carers, and to the professionals who work with them. They also provide support in the home, at school or at their centres of excellence.
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Reviewed: May 2015
Review due: May 2017
First published: Thursday 22 August 2013
Updated: Wednesday 17 August 2016