For many people, sight is the primary means of taking in the world around them. This complex system of light entering the eye, and being processed within the brain, allows us to perceive our position in space, and the features of our environment. When things go wrong with this system, whether within the eye itself (glaucoma, retinal tear) or within the brain (optic nerve disorders, multiple sclerosis), vision can be disrupted. Some disorders may involve a strange interpretation of visuals, such as what happens with Sensory Over-Responsivity (a subset of SPD). When this happens, a person may view visuals as a threat, or nuisance when a normal person would simply interpret the stimuli.