Patent ID: 7404825

Claim:
An implant capable of forming a differential image in an eye comprising: an elongated member having a central axis and a pair of spaced ends wherein one of said pair of ends includes a distal section which extends in a direction substantially parallel to the central axis, said elongated member and said distal section being formed of a dimension to be inserted into and passed through a punctum opening of an eye; and a radiation obstructing material responsive to electromagnetic radiation being incorporated in at least one of said elongated member and said distal section which, in use, upon everting of an eyelid of an eye and exposing the implant to electromagnetic radiation at a selected wavelength forms a differential image pattern showing the location of said implant in the eye wherein said radiation obstructing material is responsive to electromagnetic radiation at said selected wavelength and wherein said radiation obstructing material comprises a pigment comprising about 3% to about 10% titanium dioxide.