Purpose: To evaluate aggressive posterior retinopathy of prematurity (AP-ROP) with regard to inter-expert diagnostic agreement and quantitative vascular features.
Methods: Eight ROP experts interpreted 15 retinal images for AP-ROP and plus disease. Inter-expert agreement was calculated by absolute agreement for AP-ROP and plus, and kappa statistic for each expert was compared with others. Retinal vessels were analyzed by a computer-based system to calculate diameter and integrated curvature (IC). Consensus reference standards for images were developed, and quantitative parameters for arterioles and venules were compared among images with AP-ROP vs. not AP-ROP, plus vs. not plus, and AP-ROP vs. plus.
Results: Mean kappa for each expert in AP-ROP diagnosis ranged from -0.15 (no agreement) to 0.42 (moderate agreement). Nine (30 %) of 30 total AP-ROP diagnoses were also classified as not plus disease. Analysis of images with AP-ROP vs. plus showed that images with AP-ROP had higher venular IC (p = 0.04). Arteriolar IC was statistically significant between images with AP-ROP vs. not AP-ROP (p = 0.01) and plus vs. not plus (p = 0.00003). There were no statistically significant differences in diameter between image groups.
Conclusions: Inter-expert agreement with regard to AP-ROP diagnosis is imperfect. Venular curvature may be a distinguishing characteristic between AP-ROP and plus. Future studies involving quantitative features of AP-ROP will have benefits for clinical diagnosis and management.