Eye Info

Retinopathy of Prematurity

Summary: Designed to help you understand more about your eye condition, this guide has been written by our experienced eye health team.

• What is Retinopathy of Prematurity (ROP)?
• Is ROP inherited?
• What causes ROP?
• Who is at risk from ROP?
• What are the effects of ROP?
• Is there any treatment for ROP?
• How is sight affected by ROP?
• Other sources of support
• What's next?

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What is Retinopathy of Prematurity (ROP)?

The internal surface of the back of the eye is lined by a tissue, called the retina. This tissue is equivalent to the film in a camera and is responsible for the initial formation of the visual image. This is then transmitted to the brain. In order to function, the retina requires a blood supply. The normal development of this blood supply for the retina starts at 16 weeks into a pregnancy and is completed by 36 weeks.

If an infant is born prematurely, with the retinal blood vessel development incomplete, problems occur. Abnormal blood vessels may develop which can subsequently lead to bleeding and scar tissue formation. This may then stretch the retina pulling it out of position. Visual loss may result.

Is ROP inherited?

There does not appear to be any hereditary basis for this condition, i.e. it is association with premature birth and not specific families.

What causes ROP?

The lack of oxygen in areas of retina which have not developed blood vessels, results in the release of chemicals that promote the growth of new blood vessels. These blood vessels often grow in an irregular manner, for reasons that are not completely understood. The presence of large amounts of oxygen (often needed for the baby's survival) is thought to be possibly toxic to the developing blood vessels. As premature babies have underdeveloped lungs they usually require additional oxygen therapy. There are other undetermined factors also contributing.

Who is at risk from ROP?

The main risk factor is a premature birth. The condition is most common in infants with a birth weight of less than 1250 grams and a gestational age of less than 28 weeks.

What are the effects of ROP?

The milder forms of ROP may resolve spontaneously just as the more severe forms may lead to irretrievable blindness, despite treatment. Unless the ROP resolves, it exerts its effect mainly through the formation of scar tissue which then pulls the retina out of place. This may result only in a minor displacement of the area of the central vision or in a total retinal detachment. In the former case, the corrected visual acuity may be good, whereas in the latter case, even the ability to perceive light may be lost.

Is there any treatment for ROP?

Currently, treatment relies on the destruction of the areas of the retina that are without blood vessels. This becomes necessary only if the disease has reached a certain, well defined stage, as the milder forms often regress spontaneously. By destroying the retina, the stimulus for the growth of the abnormal blood vessels is removed. The destruction is achieved by cryotherapy (literally freezing the retina, using a small pulse) or photocoagulation with laser energy. Rarely, surgery is undertaken in an attempt to remove the scar tissue. To prevent ROP, Paediatricians attempt to minimise the amount of supplemental oxygen the infant is receiving.

How is sight affected by ROP?

This is very dependent on the birth weight and gestational age of the infant, as this has a direct influence on the extent of the disease. The disease does not present itself until the time that the normal blood vessel growth would approach completion, ie at 32 weeks of the adjusted gestational age. 5 per cent of premature infants will have some scarring changes associated with ROP and 1.2 per cent will be blinded by it. Other late complications may develop (such as cataract and glaucoma).

Other sources of support

Low Vision Services

Low Vision Services exist to optimise vision by the use of techniques, aids, lighting and general information. The eye specialist will be able to advise you on the nearest Low Vision Clinic within the Hospital Eye Service offering an equipment loan service.

General

RNIB is not aware of any support group for this condition, however the following may help:

LOOK is an organisation that seeks to identify sight related support groups and put parents in contact. They have regional representatives and their national office can be contacted.

LOOK UK
Queen Alexandras College
Court Oak Rd
Harbourne
Birmingham
B17 9TG
Tel 0121 428 5038

The Partially Sighted Society
7 - 9 Bennetthorpe
Doncaster
South Yorkshire
DN2 6AA

Tel: 0844 477 4966
Fax: 0844 477 4969

Will be able to advise on Low Vision Services, lighting and aids.

What's next?

Our Adapting to sight loss page gives information useful for people with a newly diagnosed sight problem.

If you need more information contact our Helpline on 0845 766 9999 or 020 7388 2525 / helpline@rnib.org.uk (some callers may find it cheaper to call a landline, so we have detailed both 08 prefixed numbers and landline equivalents where available).

RNIB does not comment on every trend or development but, when a treatment becomes established / recognised, we revise our website material to include it.

Unfortunately, RNIB can only answer email enquiries from the UK. But you may find an organisation for people with poor sight in your country through our agencies database.

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Content author: eyehealth@rnib.org.uk

Last updated: 06/03/2008 15:41