How common is ROP?
In the UK, about 65 per cent of babies who have a birth weight of less than 1,251 grams will have ROP. However, the majority of these babies will have mild ROP that doesn’t require treatment. There are only around six per cent of premature babies that will have advanced ROP requiring treatment (stages 3, 4 or 5).
The incidence of ROP is on the rise as more and more babies now survive when they are born prematurely. This means that there are more babies with ROP. Treatments are now offered at an earlier stage than in the past, so the sight threatening severe forms of ROP (stage 4 and 5) are rare.
How is ROP diagnosed?
All newborn babies that weigh less than 3lbs or 1,501g or babies born at or before 32 weeks of pregnancy will have at least one eye screening examination. An ophthalmologist will perform the screening and can diagnose retinopathy of prematurity. The first eye examination is done a number of weeks after birth. The timing of this is determined using a table based on the baby’s gestational age at birth.
Eye drops will be placed into the baby's eyes to enlarge the pupil which is necessary for the ophthalmologist to view the retina inside the eye clearly. Anaesthetic drops are also used so that the baby doesn’t feel any pain.
The ophthalmologist will use a special lens and light to view the retina which often only takes a few minutes. Often the doctor will use a speculum or a clip to help keep baby’s eyelids open while looking in the eye. They may also use an indentor, which is a tiny rod, to press gently on the eyeball so that the doctor can have a thorough look inside the eye. It’s not uncommon for your baby to cry during the procedure. Some centres may use a special camera to take pictures of the retina.
This screening will happen weekly or fortnightly until the risk of developing ROP requiring treatment has passed. If a baby has some signs of ROP then these examinations will continue until your baby’s due date.
Following the eye examination, the ophthalmologist will then decide whether treatment is required.
What is the treatment for ROP?
Many babies with ROP don't need treatment as it often resolves on its own.
If new blood vessels start to grow then treatment can be used to stop them causing more damage. Some babies will need more than one treatment. Usually treatment is done using a laser machine, but in certain circumstances treatment is done by injecting a drug into the eye. Treatment for ROP can be a distressing time for both parents and baby.
A baby will need to go on a ventilator which is a breathing machine and be intubated where a breathing tube is inserted in baby’s mouth for treatment; this means that your baby will be unconscious for the whole treatment. This is to ensure they are completely still and don’t experience any pain while the treatment is happening. Your baby’s heart and breathing are carefully monitored during the treatment. The treatment can take between one and two hours to complete. Most babies stay on the breathing machine for a day or two but sometimes can take longer to come off breathing support.
The treatment uses a laser to make small burns on the retina inside the eye. This can stop the new blood vessels from developing. Although the laser helps to safeguard vision, it can affect your baby’s peripheral or side vision.
Once the treatment is finished your baby’s eye may look red and swollen. Eye drops may also be required following treatment for a week or so, but the eye will no longer be painful. The baby's eye will need to be examined in about a week's time to check if the laser treatment has worked. Sometimes, further treatment will be required.
Another possible treatment option that is sometimes required for ROP is anti-vascular endothelial growth factor (anti-VEGF). The term “anti” means “against” and “vascular” refers to blood vessels. Anti-VEGFs are drugs that stop blood vessels from forming or growing and are given by injection into the eye. In the UK this treatment is for babies who do not respond to laser treatment or who are too sick to go back on the breathing machine. It is still not known what affect anti-VEGF injections into the eye might have on blood vessel development elsewhere in a baby, in particular on brain development.
In most babies early treatment is usually successful. This means that the abnormal blood vessels stop developing and a retinal detachment doesn't occur. In some babies the treatment may stop the retina from detaching, but their vision may still be affected; they may not recover all their sight after treatment.
In a baby with stage 4 ROP, surgical treatment such as a vitrectomy may be done. A vitrectomy procedure involves removing the vitreous gel in the eye and replacing it with a clear solution. The solution then holds the detached retina against the back of the eye. Some useful vision may be preserved by this type of surgery, especially if it is done very soon after stage 4 ROP has developed. Unfortunately, surgical treatment for stage 5 ROP rarely achieves useful vision.
How will ROP affect vision?
Vision in children develops from when they are born up until they are around seven years old. It’s not possible for doctors to know what a baby's vision is like until at least six weeks after their original due date when vision “switches on”. Even then, as vision continues to develop during childhood, it may not be possible to know what a child’s vision is like until they are much older. However, doctors will be able to give an approximate estimate of how well each child is likely to be able to see, based on the health of the eyes, and of the brain.
Vision development depends on the health of the visual nerve pathways in the brain as well as of the eyes. Premature babies can have some areas of brain injury, usually caused by bleeding into the brain soon after birth. Unfortunately, some children who were born prematurely have poor vision due to brain injury, even if their eyes have not been damaged by retinopathy of prematurity.
Babies who have stage 1 and stage 2 ROP may not have any vision problems and therefore won’t usually require regular eye exams by an ophthalmologist. Often babies in Stage 1 and 2 would then only need to have the national vision screening which begins in school age at around the ages of 4-5 years. This is a vision check to make sure vision is developing normally in children. If you have any future concerns about your child’s eyes or vision, you should speak to your GP or optometrist (optician) who would be able to refer your child to an ophthalmologist.
Babies who have stage 3 ROP may be followed up in the hospital clinic according to the centre's protocol as they may be more likely to have eye problems. Babies who have had treatment will be regularly monitored for myopia or short sightedness and whether there are any long-term effects from the laser scars which can occasionally affect vision.
It’s likely that babies who have stages 4 and 5 ROP will have significant vision loss. Although vitrectomy surgery is successful in some of these babies, many have a poor visual outcome.
Although the incidence of ROP is rising due to more premature babies surviving, our knowledge and understanding of the condition has also increased. The number of babies with ROP requiring treatment still remains very small. There have been great improvements in the screening, diagnosis and treatment of ROP which has led to better visual outcomes for these children.
Babies who are born early are at higher risk for having vision problems, which aren't caused by ROP, when they grow older. Some of these problems may include:
- myopia or short sightedness
- brain injury.
Myopia or short sightedness and squint can normally be corrected with glasses. Vision problems due to brain injury may be severe, and are then apparent at an early age. However, they may be mild and subtle and are then only recognised at an older age. Some of these milder problems consist of an inability to cope with a crowded visual environment (“crowding”), and reduced awareness of the lower visual field which can result in clumsiness while walking.