The future of screening for retinopathy of prematurity.

Modern treatment strategies have resulted in a dramatic improvement in the visual prognosis of infants diagnosed with severe retinopathy of prematurity (ROP) as long as intervention occurs before the onset of retinal detachment. Thus, to be effective, infants requiring treatment need to be identified in a timely fashion. The treatment window for threshold ROP is typically 2 or 3 weeks after diagnosis but may be a week or less in rapidly progressing disease. Recognizing the urgency of timely intervention, the American Academies of Ophthalmology and Pediatrics, and the American Association for Pediatric Ophthalmology and Strabismus have recently published revised screening guidelines. 1 These recommendations call for an experienced ophthalmologist to perform serial binocular indirect ophthalmoscopic examinations until treatment is required or the risk of developing threshold disease has passed. While highly effective in identifying infants in need of treatment, this paradigm is labor intensive and potentially traumatic to the infant. Furthermore, serial ophthalmologic examinations may not be practical in rural areas or developing countries, where ROP can be the leading cause of childhood blindness. 2,3 The goals of an efficient screening program are to detect treatable disease at as high a rate as possible and to minimize the number of examinations that yield normal findings or do not alter the course of clinical care. When the number of at-risk infants is large and the requirement for surgical intervention infrequent, it is reasonable to investigate alternative screening strategies that might improve efficiency. These can be grouped into several categories: 1. Eliminate superfluous examinations. It has been suggested that a savings of more than 1.5 million examinations annually in the United States could be expected if screenings were omitted for infants with birth weights of 1500 g or more, or gestational ages 32 weeks or more postconception, while missing no patients with clinically important ROP. 4 Strategies applying birth weight and gestational age criteria simultaneously have also been proposed 5 to define better the onset of risk and potentially eliminate unnecessary early examinations when the child is most vulnerable to stress or injury. However, validation of such methodologies with a large database of patients from multiple institutions (such as the CRYO-ROP Multicenter Clinical Trial) is currently lacking. It is also known that, on occasion, threshold disease may occur in infants with birth weights over 1500 g, some of whom may progress to retinal detachment without treatment. Therefore, a superfluous examination is difficult to define. 2. Abbreviate the screening process in low-risk infants. There is a significant correlation between the appearance of posterior pole retinal vessels and the severity of ROP in the retinal periphery. Specifically, the presence of normal posterior pole vessels does not seem to be associated with ROP more severe than stage 2. 6 This allows a quick screen in infants in whom the retinal periphery cannot be adequately visualized or who are medically unstable. Identification of posterior pole vascular abnormalities can even be made with a reasonable degree of accuracy by a trained neonatologist using a direct ophthalmoscope. 7 Such a strategy using