Screening for retinopathy of prematurity: is it painful?

Background: Screening programmes for retinopathy of prematurity have shown to reduce unfavourable visual outcome and to be cost-effective. Following present recommendations, almost 1% of all newborn babies should therefore be screened and undergo at least one ophthalmologic examination. This is a skilled procedure that requires drug instillation and manipulation of the ocular globe with scleral indentation. The objective of this study is to describe the side effects of this ophthalmic exam with special focus on the occurrence of pain.

Methods: This was an observational study with a before-after analysis where all neonates undergoing an ophthalmologic exam during a 4-month period in a third level hospital were included. CRIES pain score was determined before the exam, 5 min after and 24 h after the screening manoeuvre. Blood pressure and pulse rate were determined in addition to the mentioned measurements 30 min after the ophthalmologic examination. Minimum oxygen saturation, apnoeas, gastrointestinal side effects (like vomiting and gastric aspirates), the need for respiratory assistance or for intensive care unit admission were recorded within 24 h before and after the procedure.

Results: 27 preterm neonates underwent an ophthalmologic examination and were included in the study. CRIES pain score was significantly higher 5 min after and 24 h after the screening procedure than before. This difference was also observed after stratification for birth weight and gestational age. No other study variable modified this time effect. No significant changes in blood pressure and pulse rate were shown after the ophthalmic exam. Vomiting was present in 4% of the newborns, gastric aspirates in 22% and apnoeas in 41% after the examination. Ten percent of the explored preterm babies needed increased respiratory assistance and 4% had to be transferred from the intermediate care unit to the intensive care because of severe apnoeas.

Comments: An increase in pain score was shown after retinopathy of prematurity screening examination. Physiologic variable changes do not last long enough to evaluate the impact of certain procedures. Multivariate pain scores (like CRIES) should be used in everyday practice. It seems that the ophthalmologic examination in preterm babies might be painful and further studies should identify the best strategy to prevent pain during the retinopathy of prematurity screening manoeuvre.