Premature babies may suffer retinal changes, known as retinopathy of prematurity (ROP). Severe forms of ROP require treatment, often with laser, to prevent the disease progressing and causing detachment of the retina, sight deterioration and even blindness. Premature babies, even those without ROP, also have an increased risk of other eye and sight problems, especially various forms of refraction errors and squints.
The EXPRESS study includes eye examinations in the neonatal period, and at the ages of two and a half and six and a half. In the neonatal period, eye examinations are carried out every week or every two weeks to identify the children who have ROP to such an extent as to require treatment. Of the 506 children in the EXPRESS study who survived long enough for complete ROP examinations to be carried out, 73% had some form of ROP and 20% had such severe ROP that they required treatment, in most cases with laser. The risk of ROP, and especially ROP requiring treatment, was greatest among the most underdeveloped children. Detailed analyses of the progress of ROP also showed that the most underdeveloped children developed ROP earlier, and required earlier treatment. However, no children required treatment before reaching week 32. It is important to take these factors into account in the care of extremely premature babies, especially when considering transfer to their home hospital. The results of the eye section of the EXPRESS study have led to modification and improvement of national recommendations in Sweden for routines and criteria for eye examinations on premature babies in the neonatal period (swedeye.org).
At the age of two and a half, the children’s sight was tested, usually at a regional hospital in Sweden. The examination included tests of the children’s sight, any squints, stereoscopic vision, refraction errors, and an assessment of the various parts of the eye, especially the retina. The results showed that one third (33%) of the children had some form of sight or eye problem. Four children (1%) were blind in both eyes, and a further four in one eye. Squints were identified in 14% of the children and a quarter of the children had refraction errors. As expected, the children who had had severe ROP had the greatest likelihood of sight and eye problems. Examinations at the age of two and a half are of course relatively rudimentary, and the examinations at six and a half will provide a significantly more detailed picture of the children’s sight. It will then also be possible to compare with the sight of a control group of children born at full term who have also undergone the same examinations.