[caption id="attachment_743" align="alignleft" width="223"] This zombie, from AMC's The Walking Dead, has eyes that show signs of decomposition, notably Tache noir de sclerotique (a reddish brown discoloration of the iris and sclera).[/caption] An interesting trait often assigned to zombies in fiction is a keen sense of sight. I believe, however, there are several factors that would make the opposite more likely. The first is that humans, on average, do not have all that great of eye sight. Approximately 75 percent of adults in the United States use some sort of vision correction, either glasses or contact lenses. Another one half of one percent of all Americans are totally blind. A blind or near-sighted zombie would create a blind or near-sighted zombie. In addition to simple vision issues corrected by lenses, humans are susceptible to a host of eye illnesses including macular degeneration, glaucoma, cataracts and retinal degeneration. These diseases would serve to further hamper the vision of zombies. And finally, there is the little matter of decomposition. Even if the natural rate of decomposition is slowed in a zombie, it is still ongoing. This is important to note because the eyes are among the first things to go. Decomposition of the eye begins within an hour of death. Blood in the eye becomes lumpy and moves toward the surface, the eye loses its surface tension and becomes misshapen and bulgy and then Tache noir de sclerotique (a reddish brown discoloration of the iris and sclera) set it. Taking the rapid rate of decay of the eye into consideration, it is possible that a zombie would be completely blind well before the rest of its body stopped functioning.