The authors, before starting the discussion about ultrasound findings in infants with ROP, present a review of the history of ultrasound in this disease. Early A-scan reports are mentioned while the B-scan literature from 1984 to 1988, consisting of seven papers, is reviewed extensively. The most important echo patterns in the various stages of the disease are described along with the most intriguing ones. There is disagreement as to whether it is always possible to show by echography if the retina is in place or not. This is due to the fact that the acoustic properties of the retina seem sometimes to change as time goes by and is quite independent of any technical difficulties which are still very great and the know-how of the examiner.
