Ocular US in a 25-year-old woman with trisomy 21 and persistent hyperplastic primary vitreous. Axial US image shows a right eye that is smaller than normal, with a linear echogenic tract extending from the posterior surface of the lens to the posterior ocular wall representing the fibrovascular remnant (arrow). Colour Doppler shows arterial blood flow within the band that corresponds to persistence of the hyaloid artery (dotted arrow). Note also the cataract