Featured is the ChromaGen haploscopic contact lens system for improving defective colour vision. Contained within the set is a booklet by D A Harris 'ChromaGen Clinical Procedures'. Most colour blindnes is inherited, and affects more men than women. The condition is also known as Daltonism, after the chemist John Dalton (1766-1844), who suffered from it, and usually involves confusion between red, green and yellow.
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