It is surprising how little has been written on the Lidless Eye in The Lord of the Rings. After all, imagery of the Eye is ubiquitous and it is the only form in which the arch-antagonist, Sauron, manifests himself. Sauron is the Eye. Besides, Sauron's Eye is his most important means of attack, and nearly all his other weapons are connected with it. The Ring is a conduit for the Eye's power and is felt as an eye by its keeper (I, 43)1 long before the connection is known. The Ringwraiths were originally drawn to the Eye by means of similar rings and have, in effect, become lesser Eyes under Sauron's domination; they are the only other beings in the trilogy said to have "lidless eyes" of their own apart from Sauron (II, 302). All of Sauron's various slaves have the Eye marked either upon their armor (I, 18), their banners (III, 164) or their bodies (Ill, 198). These facts suggest that the Eye somehow represents the essence of the evil forces at work in the trilogy. Perhaps most of Tolkien's critics have found the Eye's role too overt and unambiguous to require much analysis. Yet, like many obvious things, it can profit from a closer look. In the trilogy Sauron's Eye works to produce two separate effects: the Gorgon effect and the Basilisk effect. Examination of this can enrich our understanding of the trilogy.
Hood, Gwenyth E. “Sauron as Gorgon and Basilisk.” VII: An Anglo-American Literary Review 8 (1987): 59-71.