This paper reviews optical compensation schemes for the elimination of off-axis light leakage in an in-plane-switching LCD. The dark-state light leakage of visible light is studied by using simulation software. Firstly, the method of optical compensation using biaxial membrane is summarized. The performance of the compensation methods that use two biaxial films is much better than that of the compensation methods using one biaxial film. Then, six methods of optical compensation using uniaxial films were investigated, and the methods of off-axis light leakage close to zero were obtained. Finally, we calculated the angle and wavelength dependence of the eight compensation methods. Optical compensation to improve the wide-viewing-angle characteristics is essential in a liquid crystal display (LCD).