Impact of number and quality of retinal images in a telemedicine screening program for ROP: results from the e-ROP study

Background: Telemedicine for the detection of retinopathy of prematurity (ROP) is becoming increasingly common; however, obtaining the required multiple retinal images from an infant can be challenging. This secondary analysis from the Telemedicine Approaches to Evaluating Acute-Phase Retinopathy of Prematurity (e-ROP) study evaluated the detection of referral-warranted ROP (RW-ROP) by trained readers when a full set of 5 retinal images could not be obtained.

Methods: A total of 7,905 image sets from 1,257 infants in the study were evaluated. Retinal location of images and image quality were recorded. Sensitivity and specificity of RW-ROP detection by trained readers were calculated by comparing findings in incomplete image sets to the findings on standard eye examination.

Results: The majority of image sets contained all 5 retinal images (92.8%). The disk center view was the image most likely to be present and to be of acceptable image quality (96.8%). The nasal retina was the most difficult to obtain with acceptable image quality (83.4%). Sensitivity of detection of RW-ROP was 82.1% when 5 retinal images of acceptable quality were submitted for grading, 67.2% when 4 acceptable images were submitted, and 66.7% for 3 or fewer acceptable images (P = 0.02), with corresponding specificity of 82.2%, 89.0%, and 81.7% respectively (P < 0.0001). When images of any quality were evaluated, sensitivity was not increased (P = 0.74).

Conclusions: The likelihood of detecting RW-ROP by telemedicine screening is decreased when a full set of retinal images is not obtained.