High Index Lenses are a type of eyeglass lens specifically designed to be thinner and lighter than standard lenses, making them an ideal choice for individuals with strong prescriptions for nearsightedness, farsightedness, or astigmatism. They achieve this by using materials with a higher refractive index (typically above 1.50, such as 1.61, 1.67, or 1.74), allowing the lens to bend light more efficiently. As a result, less material is required to achieve the same corrective power, resulting in slim, lightweight lenses that are more comfortable and aesthetically pleasing.