Color Changing Contact Lens

contact lens
contact: a thin curved glass or plastic lens designed to fit over the cornea in order to correct vision or to deliver medication
A contact lens (also known simply as a contact) is a corrective, cosmetic, or therapeutic lens usually placed on the cornea of the eye.
A thin lens, made of flexible or rigid plastic, that is placed directly on to the eye to correct vision, used as an alternative to spectacles, or, if coloured, to change one's eye color cosmetically
A thin plastic lens placed directly on the surface of the eye to correct visual defects

changing
(change) an event that occurs when something passes from one state or phase to another; "the change was intended to increase sales"; "this storm is certainly a change for the worse"; "the neighborhood had undergone few modifications since his last visit years ago"
Make or become different
Make or become a different substance entirely; transform
cause to change; make different; cause a transformation; "The advent of the automobile may have altered the growth pattern of the city"; "The discussion has changed my thinking about the issue"
Alter in terms of
marked by continuous change or effective action

color
The use of all colors, not only black, white, and gray, in photography or television
add color to; "The child colored the drawings"; "Fall colored the trees"; "colorize black and white film"
having or capable of producing colors; "color film"; "he rented a color television"; "marvelous color illustrations"
The property possessed by an object of producing different sensations on the eye as a result of the way the object reflects or emits light
One, or any mixture, of the constituents into which light can be separated in a spectrum or rainbow, sometimes including (loosely) black and white
a visual attribute of things that results from the light they emit or transmit or reflect; "a white color is made up of many different wavelengths of light"