Uhtoff's phenomenon = Uthoff's phenomenon refers to visual problems that occur in persons with MS that are brought on during periods of increased body temperature. The usual history is of "black spots" appearing in the visual fields of one or both eyes while the person is exercising, in the sauna, taking a hot shower, or having a fever. This phenomenon is felt to reflect areas of impaired but still functioning myelin that breaks down in transmitting electrical impulses when the surrounding fluid heats up.
More ophthalmic eponyms