Nulux EPO has an aspheric surface on the convex side and atoric surface on the concave side. his allows the wearer to enjoy maximum field of clear vision as distortion is kept to the minimum
Hoya's aspheric lens has its flat surface only on the convex side. It order wider undistorted field of vision as compared to a spheric lens but this is relatively narrower than a double aspheric lens.
Due to its curvature (non-flat surface), distortion is more apparent at the periphery ares of a spherical lens. Therefore, a smaller range of clear viewing zone for it wearer.