Are you a very nearsighted or very farsighted person who has such a strong lens prescription that the thickness and weight of your prescription lenses limit your selection of eyeglass frames? If so, you should know that choosing “high-index” lenses over traditional lenses can make a huge difference. Because high-index lenses can bend light to a higher degree than traditional lenses, they are 20% to 65% thinner than standard plastic lenses. The stronger the prescription, the greater the difference in thickness between high-index lenses and traditional lenses can be expected to be. Because high-index lenses provide the same optical clarity in a smaller package, those with more severe optical errors can use them in a greater array of fashion frames. Modern lenses come in a variety of materials. The lens that is best for you depends on your vision problem, lifestyle, and personal preference. The higher the index of a high-index lens material, the better it is able to bend light.