Retinopathy of Prematurity (ROP)

What's going on?

The neonatal eye is not fully developed. Normally, the retina grows out, sweeping over the retinal pigment epithelium (RPE) from the optic disc to the periphery. This growth is stimulated by ischaemia of the bare patches of RPE. If the baby is premature and has high concentrations of supplementary oxygen, however, the RPE cells are not ischaemic and thus fail to stimulate the retina to grow. When the supplementary oxygen is removed, the RPE cells are suddenly rendered profoundly hypoxic. In attempting to 'catch up', they overstimulate retinal growth, causing new vessels to grow and fibrovascular membranes to form. This condition is called retinopathy of prematurity (ROP) and, if untreated, can be blinding.

If I examine the patient, what will I find?

The view may be hazy, the disc hyperaemic and the blood vessels tortuous and dilated. In the periphery will be a patch of pale retina with no blood vessels on the surface (although this is very peripheral and you are unlikely to see it).

In older patients with burnt-out ROP, you may see a 'dragged' disc, with the blood vessels looking as though they have been 'dragged' towards the periphery.

What will the hospital do?

Babies who are under 32 weeks' gestation or weigh less than 1500g at birth are screened for the presence of ROP. Different centres use different criteria for screening.

The decision about when to treat babies with ROP is made based on the findings of a large study

The ischaemic area of retinal pigment epithelium is usually killed off by laser therapy under general anaesthesia.

What to tell the patient

If treated early enough, the prognosis for long-term normal vision is generally good, although less so for very premature babies.

Problems that may arise, and how to deal with them

Premature babies are at increased risk of other ocular problems, including refractive error (usually myopia) and squint. If you notice these, then referral routine via letter is appropriate.