Noise sensitivity may develop as a result of an abnormality in the middle or inner ear. Trauma to the ear may cause noise sensitivity. Noise sensitivity may be present with migraine headaches. Noise sensitivity may occur as a side effect of certain medications. Noise sensitivity may occur as a result of an ear infection. People with misophonia find it impossible to tolerate certain sounds.
Equal division lenses, segmented bifocals and blended lenses â also called seamless or invisible bifocals â are three main types of bifocals. Equal division bifocal glasses feature lenses cut in two distinct halves, with the magnification part on the lower half and the long-distance lens on the upper half. The initial version of the equal division lenses, called the executive cut, had a visible horizontal line directly across the lens.
A modern replica pair of the type of split bifocal spectacles known to have been worn by Benjamin Franklin in the mid 1780s. Bifocals are eyeglasses with an upper and lower half, the upper for distance, and the lower for reading. Bifocals are commonly prescribed to people with presbyopia, a condition that Franklin suffered. Franklin wrote, in August 1784 to his friend George Whatley, that he was happy in the invention of double spectacles, which serving for distant objects as well as near ones, make my eyes as useful to me as ever they were..