When it comes to sensory functions, the eyes have been the focus of much attention from researchers and drug developers, resulting in last year's breakthrough for Spark Therapeutics Inc. with the FDA nod for gene therapy Luxturna (voretigene neparvovec-rzyl) to treat children and adults with confirmed biallelic RPE65 mutation-associated retinal dystrophy, an ultra-rare disease that leads to vision loss and, sometimes, blindness.