The human body is a complex system, and unfortunately, it is not immune to the invasion of parasites. Parasites, when they enter the human nervous system, can target vital organs such as the brain, spinal cord, and even the eyes. While our eyes are shielded by a protective sac and seemingly impervious to external threats, various parasites have found their way inside, causing a range of distressing symptoms, from swollen eyelids to, ultimately, blindness.