Objectives: To compare the method of photographic screening using the RetCam 120 to the standard method of screening for retinopathy of prematurity (ROP) by ophthalmologic examination.
Methods: A total of 100 RetCam 120 photoscreening examinations of the retina were performed on 32 premature infants. These were stored in a separate file from which all identifying information was removed. At this same examination, a detailed ophthalmological evaluation, employing the indirect ophthalmoscope with scleral depression, was performed by an experienced examiner. Masked examiners performed an evaluation of the fundus photographs to identify presence or absence of ROP, the location and extent of the disease, and the presence or absence of plus disease. These data were then compared with the results of the ophthalmological examination to determine the specificity, sensitivity, and the positive and negative predictive value (PPV and NPV) of the method.
Results: Retinopathy of prematurity was detected in 68 of 100 subjects by ophthalmologic examinations and in 58 of 100 subjects' photoscreening examinations. No ROP was detected in 32 of 100 subjects. The sensitivity of the method was 56 (82.4%) of 68 and the specificity was 30 (93.8%) of 32. The PPV was 96.6%; NPV, 76.9%.
Conclusions: The sensitivity of the method was low. The ROP that was missed was peripheral stage 1 or stage 2 disease in peripheral zone 2 or zone 3. This was largely due to the technical limitations of the speculum-camera interface preventing a better view of the periphery. The ROP cases that were missed by the photographic examination regressed spontaneously on follow-up. No disease more posterior to peripheral zone 2 was overlooked. These results detail the accuracy of the method employing the technique of photoscreening as a potential substitute for detailed ophthalmological examination. At present there are clear technical limitations to such a substitution. The study is part of an ongoing project to determine the feasibility of employing neonatal nurses trained to take digitized images of the premature infant's retina and telemeter the results to be read by an experienced ophthalmologist remote from the site.