A single staring eye set within an ornate diamond frame is widely used as a protective symbol, drawing on the broad folk belief that an eye motif wards off ill will or the "evil eye" cast by envious onlookers. This particular rendering mixes the eye with scrollwork and Sacred Heart-style flourishes rather than the classic Turkish nazar blue-glass disc, so the reading here leans more toward general protection and vigilance than one specific tradition. People choose it as a guardian symbol, a nod to perception and awareness, or simply for the strong graphic look.
Where it sits
The design is a symmetrical diamond, wider in the middle and tapering to points top and bottom, which suits the forearm, upper arm, sternum, or the center of the back where that elongated shape has room to sit straight. It also works on the thigh or calf if oriented vertically. Shrinking it much below palm size will blur the fine radial line work in the eyelids and lose the small red and yellow petal details at the corners.
Making it yours
Ask an artist for any of these.