Retinoblastoma (Rb) is a rare form of cancer that rapidly develops from the immature cells of a retina, the light-detecting tissue of the eye. It is the most common primary malignant intraocular cancer in children, and it is almost exclusively found in young children.Though most children survive this cancer, they may lose their vision in the affected eye(s) or need to have the eye removed. [Source: Wikipedia 
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