To provide a functional spectral filter through which, it is possible for an observer wearing the functional spectral filter to change his or her color sensitivity, and which is for designing a color scheme easy to be distinguished for a color deficient observer by using the filter. A pressing ring 23 is held at the advance position together with an operation sleeve 22 by a guide washer 24 forced by a coil spring 25. Kits and methods for using the interactive packages and particularly the interactive portions of the packages are also disclosed.