Sensitivity and specificity of individual computer system parameters and linear combinations of parameters for plus disease diagnosis, compared to the reference standard of majority vote among 22 recognized ROP experts. Curves are displayed as a function of parameter cutoff criteria for detection of plus disease: Upper left, arteriolar integrated curvature (IC). Upper middle, arteriolar diameter. Upper right, arteriolar tortuosity index (TI). Center left, venular IC. Center middle, venular diameter. Center right, venular TI. Lower left, Linear combination I (arteriolar IC and venular diameter). Lower middle, Linear combination II (arteriolar IC, venular IC, and venular diameter). Lower right, Linear combination III (arteriolar IC, arteriolar TI, venular IC, venular diameter, and venular TI).