Ridge Thickness As a Predictor of Disease Progression in Retinopathy of Prematurity Using Ultra-widefield Optical Coherence Tomography

Purpose To investigate if there is a threshold thickness of retinopathy of prematurity (ROP) stage 2 disease (elevated ridge) that correlates with progression to stage 3 disease (retinal neovascularization). Design Case-control study Subjects 35 consecutive neonates at the Oregon Health & Science University (OHSU) neonatal intensive care unit (NICU) undergoing regular screening visits for retinopathy of prematurity Methods Longitudinal ultra-widefield OCT (UWF-OCT) imaging was used to obtain images from participants (15 neonates who did not develop stage 3 disease and 20 neonates who developed stage 3 disease) during regular ROP screening visits. Using a previously validated u-net model, the ridge was segmented on en face images and the ridge height was measured on cross-sectional B-scans for those segmented regions. Statistical analysis was conducted using a two-sided unequal variance T-test (p<0.05) and Youden’s J-index. Main Outcome Measures Ridge height in microns for each study group. Threshold ridge thickness that correlates with progression to stage 3 ROP (neovascularization). Results There was a significant difference in stage 2 ridge height between the 15 neonates who peaked at stage 2 disease (282.6 microns, SD 39.7) and the 20 neonates who progressed to stage 3 (366.7 microns, SD 72.2; p < 0.001). Youden’s J-index suggests a maximum stage 2 thickness of greater than or equal to 289 microns had a 95% sensitivity and 67% specificity for progression to stage 3. Ridge heights appear similar between the two groups until 10 to 11 weeks chronological age, when ridge heights for neonates who go on to reach stage 3 disease typically pass the threshold of 289 μm. Conclusions When ROP stage 2 ridge height exceeds 289 microns, the odds of progression to stage 3 disease rise sharply. This inflection point towards retinal neovascularization may inform future OCT-based ROP risk models.