Should be used if the eye is shiny/is reminiscent of glitter.
Examples:
post #6220808
post #4341265
Two examples of a glowing eyes with eye_glitter:
post #6065632
post #5776818
Use this tag for posts like post #6215284. Even when looking at the eyes close up, a viewpoint from which the brush strokes in the eyes look like brush strokes, from afar (the normal viewpoint) they are still shiny and reminiscent of glitter.