The authors evaluated 36 patients (72 eyes) who had either Stage 4 or Stage 5 retinopathy of prematurity (ROP) with standardized A-scan and B-scan echography. The eyes were evaluated for vitreous opacities, retrolental membranes, and retinal detachments. Stage 5 retinal detachments were present in 94% (68 of 72) of the eyes with 65% (47 of 72) having a wide anterior and narrow posterior configuration. Anterior retinal loops were noted in 36% of the eyes. Subretinal opacities were present in 47% of the eyes. Choroidal thickening and intraocular calcium were noted in 22% and 14% of eyes, respectively. The axial eye length was measured and adjusted for the differences in chronological and gestational age and compared with data from normal eyes. This showed that eyes with ROP were much smaller. The standardized A-scan was helpful in confirming the diagnosis of retinal detachment, evaluating the peripheral retina, and examining the subretinal space. The combination of A-scan and B-scan echography is helpful in predicting anatomic findings in patients with ROP undergoing surgery.