Although both Greenland and Vinland in North America were settled by Viking explorers and traders, neither was destined to be a permanent Norse population center. Greenland experienced climate change over the next few centuries, and all the farms and settlements were abandoned by the turn of the 16th century.
Eye floaters can appear as black or gray dots, lines, cobwebs, or blobs. Occasionally, a large floater may cast a shadow over your vision and cause a large, dark spot in your sight. Because the floaters are inside the fluid of your eye, they will move as your eyes move.
Doctors first ask questions about the person's symptoms and medical history. Doctors then do a physical examination. What they find during the history and physical examination often suggests a cause of the floaters and the tests that may need to be done (see Table: Some Causes and Features of Eye Floaters).