The object of convergence is the directing of the yellow spot in each eye towards the same point, so as to produce singleness of vision; diplopia, or double vision, at once resulting when the image of an object is formed on parts of the retina which do not exactly. correspond in the two eyes.
Hives are red, itchy, slightly elevated swellings. Itching may be severe. Hives have clearly defined borders and may have a pale center. Typically, crops of hives come and go. One hive may remain for several hours, then disappear, and later, another may appear elsewhere.
Hives facts. 1  Hives (medically known as urticaria) are red, itchy, raised areas of skin that appear in varying shapes and sizes, each one characteristically lasts no longer than six to 12 hours. 2  Hives are very common, and most often their cause is elusive.