'Teichopsia' is seen in

Ans. B. Migrane. (Ref Victor Adams Neurology, pg. 182-183.)Classic migraine is usually familial, involves a unilateral, throbbing head pain, and diminishes in fre- quency with age. The blind spot, or scotoma, that may develop as part of the aura of a classic migraine attack will involve the same visual field in both eyes. This defect usually changes over the course of minutes. It typically enlarges and may intrude on the central vision. The margin of the blind spot is often scintillating or dazzling. If this margin has a pattern like the battlement of a castle, it is called a fortification spectrum, or teichopsia. Homonymous hemianoptic defects of the sort that develop during the aura of a classic migraine indicate an irritative lesion that is affecting one part of the occipital cortex in one hemisphere of the brain. The changes in the scotoma over the course of minutes indicate that the irritative phenomenon sets off a cascade of events in the visual cortex that temporarily disturbs vision in a progressively larger area. Other focal neurologic phenomena may precede classic migraine; the most common are tingling of the face or hand, mild confusion, transient hemiparesis, and ataxia. Fatigue, irritability, and easy distractibility often develop before a migraine. Affected persons usually also have hypersensitivity to light and noise during an attack.