Eyeglass lenses come in varying indexes from regular to high index lenses. The most common is 1.5 index which is suitable for weaker prescriptions. For stronger prescriptions, 1.5 index lenses can be used. However, in order to make the appropriate correction, the lenses need to be much thicker.
Lenses for high reading prescriptions tend to have a greater centre thickness. From an observers perspective, the lens magnifies the eyes making them look much larger. Lenses with a strong distance prescription have a thicker lens edge. These lenses have the opposite effect of minifying the eyes. The result in both cases is also a much heavier lens.
High index lenses bend the light more efficiently compared to regular index lenses. This makes them a more suitable choice for stronger prescriptions. High index lenses are available in a 1.56, 1.6, 1.67 and 1.74 index. Your Eye Care Professional will determine which index is most suitable for your prescription needs to ensure you have the thinnest and most lightweight lens option.
Although high index lenses are more expensive, the lighter weight of these lenses will ensure a more comfortable fit when you wear your glasses. The thinner lens is also more aesthetically pleasing.
High index lenses can be used for single vision, bifocal and progressive lenses. They can also be combined with various coatings. Anti-reflective coatings are a must with high-index lenses as they eliminate glare. Other options include blue-light blocking, transition and polarized sunglass lenses.