The instant disclosure describes a method for determining composition or concentration of contaminants on a film encapsulated inside a plasma display panel. The resistive storage element can be switched between a first storage state with a first conductivity and a second storage state with a second conductivity. The monitor device is adopted to monitor whether the non-inverse input signal is close to a maximum or minimum voltage of an input source of the operational amplifier. The contact lenses and the pharmaceutical composition induce a change in the radius of curvature of the anterior surface of the cornea, thereby correcting the refractive error of the eye. The knife assembly includes a knife blade biased toward an initial position, wherein the knife blade is disposed within the jaw housing.