 Researchers have noted that by using the nanoparticle loading technique, the transparency decreases by nearly 10%.Conversely, researchers have confirmed that by using the molecular imprinting and supercritical soaking methods of drug loading, the lens transparency of the contact lenses has stayed at or above the lens transparency of the contact lenses currently approved by the FDA.Oxygen permeability is another important feature of all contact lenses and much be optimized to the largest degree possible when creating drug delivery devices for the eye.