This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Miscellaneous, Subject name: Medicine
A 15-year-old boy presented with decreased vision in both eyes, and a slit lamp examination revealed this finding. What is the diagnosis? 
Select and explain. 
A. Juvenile xanthogranuloma, B. Persistent hyperplastic primary vitreous, C. Protruding iris collarette, D. Iris duplication
B: Persistent hyperplastic primary vitreous
Answer: B: Persistent hyperplastic primary vitreous 
Explanation: Answer B. Persistent pupillary membranesThe correct answer is persistent pupillary membranes (PPMs). PPMs represent remnants of the tunica vasculosa lentis, which is the blood supply for the developing lens of the fetus. Remnants of the capillaries may persist as small strands attached to the collarette of the iris. Vision is usually unaffected, but occasionally thick, persistent pupillary membranes can cause deprivational amblyopia.