Wide-field digital imaging based telemedicine for screening for acute retinopathy of prematurity (ROP). Six-year results of a multicentre field study

Abstract

Objective

To report on a 6-year experience with wide-field digital imaging based telemedicine (WFDI telemedicine) to reduce the risk for blindness from retinopathy of prematurity (ROP).

Methods

Wide-angle digital fundus cameras (RetCam 120, Massie Lab, Pleasanton, CA, USA) were installed in five neonatal intensive care units (NICUs) in Germany. All prematures at risk were screened with WFDI, and the local ophthalmologists were asked to continue binocular indirect ophthalmoscopy (BIO) according to the German guidelines. Image data were coded and transferred to the Reading Centre in Regensburg. Image evaluation and additional BIO of infants with suspected treatment-requiring ROP (STR-ROP i.e. threshold ROP zone II, prethreshold ROP zone I (type-1 ROP according to ETROP), and ROP possibly requiring treatment but not reliably classifiable from the images) were performed by paediatric ophthalmologists at the Reading Centre. ROP was classified following ICROP, ETROP, and revised ICROP criteria. Outcome measures were incidence of clinically relevant ROP (CR-ROP, i.e. any ROP up to mid-peripheral zone III, ≤ stage 3+), sensitivity to detect STR-ROP, and positive predictive value to detect treatment-requiring ROP (TR-ROP).

Results

In total, 1,222 prematures at risk were screened (mean BW 1395 g, SD ±507 g; mean GA 30 wks, SD ±3 wks). The overall incidence of CR-ROP was 27.6% (71.8% mild = stage 1 to 3 without plus disease, 15.7% prethreshold = type-1 ROP according to ETROP, 12.5% threshold according to ICROP). Zone I disease was present in 3.3%, zone II disease in 76.5%, and zone III disease in 20.2%. According to ETROP, 95 infants were type-1 or type-2 ROP; 67.4% type-1 ROP, and 32.6% type-2 ROP. Of all 1,222 infants, 3.5% received treatment. Following ETROP (not applied in the study), 5.3% would have been treated. The sensitivity for detecting STR-ROP was 100%, and the positive predictive value for TR-ROP 82.4% (28/34) at the time of the first referral (28 infants, ≤ stage 3+ in zone I or II).

Conclusion

All TR-ROP was detected in time, showing the potential of our telemedical screening program. The overall incidence of CR-ROP was comparable to ROP incidences reported in other West European countries.