Isolated retinal neovascularization in retinopathy of prematurity: clinical associations and prognostic implications

Objective Isolated retinal neovascularization (IRNV) is a common finding in patients with stage 2 and 3 retinopathy of prematurity (ROP). This study aims to further classify the clinical course and significance of these lesions (previously described as “popcorn” based on clinical appearance) in patients with ROP as visualized with ultra-widefield optical coherence tomography (UWF-OCT). Design Single center, retrospective case series. Participants Images were collected from 136 babies in the Oregon Health and Science University neonatal intensive care unit. Methods A prototype UWF-OCT device captured en face scans (>140°), which were reviewed for the presence of IRNV along with standard zone, stage, and plus classification. In a cross-sectional analysis we compared demographics and the clinical course of eyes with and without IRNV. Longitudinally, we compared ROP severity using a clinician-assigned vascular severity score (VSS) and compared the risk of progression among eyes with and without IRNV using multivariable logistic regression (MLR). Main Outcome Measures Differences in clinical demographics and disease progression between patients with and without IRNV. Results Of the 136 patients, 60 developed stage 2 or worse ROP during their disease course, 22 of whom had IRNV visualized on UWF-OCT (37%). On average, patients with IRNV had lower birth weights (BW) (660.1g vs 916.8g, p = 0.001), gestational age (GA) (24.9 vs 26.1 weeks, p = 0.01), and were more likely to present with ROP in zone I (63.4% vs 15.8%, p < 0.001). They were also more likely to progress to stage 3 (68.2% vs 13.2%, p < 0.001) and receive treatment (54.5% vs 15.8%, p = 0.002). Eyes with IRNV had a higher peak VSS (5.61 vs 3.73, p < 0.001) and averaged a higher VSS throughout their disease course. On MLR, IRNV was independently associated with progression to stage 3 (p = 0.02) and requiring treatment (p = 0.03), controlling for GA, BW, and initial zone 1 disease. Conclusion In this single center study, we found that IRNV occurs in higher risk babies and was an independent risk factor for ROP progression and treatment. These findings may have implications for OCT-based ROP classifications in the future.