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.
Modern Bifocal and Trifocal Lens Options. Today, you can select from many bifocal and trifocal lens designs, depending on your age and visual needs. There are even special bifocals and trifocals designed for glasses for computer work and other tasks that take place at the intermediate range. In the following images, distance describes the area of the lens used for far vision, intermediate for arm's length and near for reading vision (about 16 inches away).