Scintillating Scotoma. (Migraine Scotoma). A scotoma is a âblind spotâ in front of the vision. The visual phenomenon of scintillating scotoma usually appears like a âtwinkling shadowâ or âzig zag patternâ before the eyes.While every experience is a little different, the most common symptoms are âblack spotâ or âtwinkling blurâ appearing before the eyes.he visual phenomenon of scintillating scotoma usually appears like a âtwinkling shadowâ or âzig zag patternâ before the eyes. While every experience is a little different, the most common symptoms are âblack spotâ or âtwinkling blurâ appearing before the eyes.
Cancel. Spiders live all over the world, including trees, dry areas, wet areas, under ground and in the oceans. Discover the different varieties of spiders on the earth with information from a science teacher in this free video on spider habitats.ancel. Spiders live all over the world, including trees, dry areas, wet areas, under ground and in the oceans. Discover the different varieties of spiders on the earth with information from a science teacher in this free video on spider habitats.
Brown spiders are present in the Midwest and South Central United States, not in the coastal and Canadian border states, except when imported on clothing or luggage. Widow spiders are present throughout the United States. Although some people consider tarantulas dangerous, their bites do not seriously harm people. Spider bites cause fewer than three deaths a year in the United States, usually in children.