<prompt> Which one of the following statements, concerning persistent hyperplastic primary vitreous PHPV is not true ?a It is generally unilateralb Visual prognosis is usually goodc It may calcifyd It is most easily differentiated from retinoblastoma by the presence of exophthalmos or cataractabcbcdacbd  <response>: PHPV is almost always 90 unilateral.Visual prognosis is bad as neither conservative treatment nor surgery can improve visual acuity.There is no calcification, which is a differentiating feature from retinoblastoma.PHPV can be differentiated from retinoblastoma by presence of cataract in PHPV but not by exophthalmos. 