lidless
Lidless is an adjective describing an eye that lacks movable eyelids. In anatomy this is found in some species where the eye is protected by a transparent covering rather than by eyelids. For example, many snakes have a fixed, transparent spectacle over the eye instead of movable eyelids, so their eyes cannot blink in the usual sense. In humans and most mammals, eyelids are present, so lidless eyes are considered atypical.
In literature and popular culture, lidless is most closely associated with the phrase lidless eye, used to
Beyond Tolkien, the term can be used more generally to describe a gaze that is relentless, unblinking,