Screening for retinopathy of prematurity employing the RetCam 120 - Sensitivity and specificity

Objectives: To compare the method of photographic screening using the RetCa m 120 to the standard method of screening for retinopathy of prematurity (R OP) by ophthalmologic examination. Methods: A total of 100 RetCam 120 photoscreening examinations of the retin a were performed on 32 premature infants. These were stored in a separate f ile from which all identifying information was removed. At this same examin ation, a detailed ophthalmological evaluation, employing the indirect ophth almoscope with scleral depression, was performed by an experienced examiner . Masked examiners performed an evaluation of the fundus photographs to ide ntify presence or absence of ROP, the location and extent of the disease, a nd the presence or absence of plus disease. These data were then compared w ith the results of the ophthalmological examination to determine the specif icity, 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 o phthalmologic examinations and in 58 of 100 subjects' photoscreening examin ations. No ROP was detected in 32 of 100 subjects. The sensitivity of the m ethod was 56 (82.4%) of 68 and the specificity was 30 (93.8%) of 32. The PP V 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 in terface 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 resu lts detail the accuracy of the method employing the technique of photoscree ning as a potential substitute for detailed ophthalmological examination. A t present there are clear technical limitations to such a substitution. The study is part of an ongoing project to determine the feasibility of employ ing neonatal nurses trained to take digitized images of the premature infan t's retina and telemeter the results to be read by an experienced ophthalmo logist remote from the site.