Baylisascaris procyonis, is a round worm that lives in the bodies of more than 90 species of wild and domesticated animals. B. procyonis infection of humans typically results in fatal disease or severe sequelae (1,2,18-24; pers. comm., W. Murray). Clinical manifestations include eosinophilic encephalitis, ocular disease, and esoinophilic cardiac pseudotumor. Though this worm is not usually found in the eye it’s mostly common in infected organs. In this article John Mathews of Bellevue Iowa was suffering from hazy vision when he visited with his ophthalmologist the doctor was shocked to find a worm in Mathew’s eye specifically in the retina. The doctors removed this worm with a laser but the damage had already been done to the eye and Mathew will no longer be able to see out of his eye. Although this is not caused by the brain or other nerves in the body a substantial amount of doctors will first diagnose a parasite as some kind of brain problem or nerve problem. A parasite is usually found after a substantial amount of damage is already done to the host’s body because it’s not common in the States because we do not live in a third world country.
In this article is states "The three most common parasitic infections affecting the eyes are toxocariasis, loaiasis [infection with the Loa loa worm] and African river blindness," said Dr. Peter Hotez, chair of the Department of Microbiology, Immunology and Tropical Diseases at George Washington University in Washington, D.C.
this is the article of the man affected by this worm. http://abcnews.go.com/Health/Wellness/worm-eats-mans-retina-terrible-parasites/story?id=11700175#.ULd0WuTLR2A