Retinopathy of prematurity (ROP for short) is an eye problem seen in some premature babies. In babies with ROP the blood vessels in the retina have developed abnormally after birth. Most premature babies do not develop any ROP. In babies that do develop ROP it is usually mild and goes away by itself, without causing any problems with vision.

What is ROP?

ROP is a problem with the way the blood vessels develop on the surface of the retina. (The retina is the layer at the back of the eye that is like a film in a camera - see figure 1.) When a baby is born prematurely these blood vessels are immature like the rest of the baby. In most premature babies the retinal blood vessels grow properly. In some premature infants the blood vessels start to grow the wrong way. Instead of branching like a tree the vessels link up side to side and in some cases grow away from the retina towards the centre of the eye. The severity of ROP is graded from stage one to stage five. Stage one is the mildest and stage five the most severe.

We do not understand why some babies develop ROP and others do not. Much research continues to be done to solve this mystery. Serious ROP is very rarely seen in babies weighing more than 1,250 grams at birth. Many years ago ROP was more common and that was linked to excessive use of oxygen. Now the supply of oxygen to premature babies is very closely monitored and the amount of oxygen given to your baby is very carefully calculated and controlled. As a result ROP is less common but it still occurs. It is well known that the sicker and smaller a baby is the more likely it is that ROP will develop.

We cannot predict which babies will develop ROP. All babies weighing less than 1250 grams at birth will have regular eye examinations after their gestational age reaches 30 to 31 weeks. These examinations are undertaken by a medical eye specialist known as an ophthalmologist. To look at the back of a baby's eyes the pupil (black circle in the middle of the coloured part at the front of the eye) needs to be dilated (see figure 2). Eye drops are used to dilate the pupils. The examination only takes a couple of minutes. Your baby may be minimally upset by these examinations and will settle very quickly once the eyes have been checked.

The following table gives results for babies screened for ROP at the neonatal nursery of the Royal Women's Hospital, Melbourne between July 1992 and June 2002. These results will vary from nursery to nursery and from time to time and are only intended to be a guide to give some idea of the possibility of babies of certain birth weights needing treatment. It is clear form this table that most premature infants do not develop ROP severe enough to warrant treatment.

In most babies ROP is mild and over a period of weeks the ROP gradually disappears. The ophthalmologist will check your baby's eyes every one or two weeks and you will be told the result of each examination.

Yes, but remember very few babies develop ROP that is bad enough to need treatment. At the Royal Women's, Melbourne only about 5 % of babies checked for ROP actually need treatment. Mild ROP does not need treatment as it almost always goes away by itself. If your baby needs treatment this is called threshold disease (severe stage three ROP). If your baby develops threshold ROP treatment options will be discussed with you. The treatment is generally done with laser and in 90% of babies needing treatment the ROP disappears and sight is preserved.

If your baby may need treatment more information will be given to you and you can discuss the situation with the paediatricians and ophthalmologist caring for your baby.

The nurse or doctor taking care of your baby are always the first people to ask. If they cannot answer your questions they will arrange a time for you to discuss your baby's eye problems with the ophthalmologist.

It is recommended that all babies who are small enough to have their eyes checked while in hospital should be offered an eye examination at one year of age. A small number of these children are found to have turned eyes or need glasses for clearer vision, even if they did not have any ROP while in hospital. It is strongly recommended that you make sure your baby has an eye examination at about one year of age. Depending on the finding at this check-up further eye checks may be needed.

Only some babies with birth weights less than 1250 grams develop ROP and in most of these babies the ROP is mild and goes away without treatment. Only a very few babies develop severe ROP and treatment is successful in most cases.