An improved punctum plug is more easily visualized when positioned within a punctual
canal of a recipient. The body of the plug features an outwardly exposed surface
when properly positioned, and a substance causing at least the outwardly exposed
surface to contrast with surrounding tissue, such that the use of the substance
causes the plug to be more easily visualized than if the substance were not present.
The substance, which may be disposed on the outwardly exposed surface or within
the body of the plug, may include a saturated coloration, or may be phosphorescent,
fluorescent or otherwise operative to reflect or re-radiate light to assist in
visualization. For example, the substance may include an organic or inorganic phosphor
or fluorescent material, reflective beads, quantum dots, a dye or pigment. Such
reflection or re-radiation may occur at the same or different wavelength(s) compared
to the illumination wavelength(s), whether or not either or both are within the
visible part of the spectrum. If outside the visible region, a detector may be
employed according to the invention for detecting the radiated light. A system
for determining whether or not a punctum plug is positioned within the punctal
canal of a person's eye is also enclosed, including at least one optical element
permitting the eye to view itself, to be viewed by the other eye, or by a second person.