Mid-and High Index Lenses. High index materials are classified by numbers. The higher the number, the thinner and lighter the lens. The lower numbers are Mid-index lenses, such as 1.54, 1.56, and 1.57, are thinner than glass, and nearly as strong as CR-39. High-Index. High index lense are much thinner than regular Mid-index lenses, such as 1.54, 1.56, and 1.57 are thinner than glass, and nearly as strong as CR-39. These materials are most Mid-Index. Other high index materials are classified by numbers. The higher the number, the thinner and lighter the lens. The
Bear in mind, however, that this is only a “rule of thumb” chart to be used as a general guide. Several factors, including price, should weigh in your decision to use low index, mid index, or high index lenses. If your diopter number falls between 0 and +/- 2.00, the recommended index material is 1.50. High-index plastic lenses are now available in a wide variety of refractive indices, typically ranging from 1.53 to 1.74. Lenses with an index of refraction of 1.70 or higher typically are at least 50 percent thinner than conventional plastic lenses. Also, generally speaking, the higher the index, the higher the cost of the lenses.
Jun 3, 2017 http://www.opticiansfriend.com/lenses.html It is a great mid index alternative for Rx ranges between +/-1.00D to +/-4.00D; also much cheaper Trivex is the lightest lens material available to date. Mid and High Index – Advantage: Thinner and lighter weight lenses. Mid-Index lenses, typically with indices Anti-Reflective Coating, High Index Lenses Mid-index lenses, such as 1.54, 1.56, and 1.57, are thinner than glass, and nearly as strong as CR-39. High-Index : Mid-Index: High index materials are classified by numbers. Again, the higher the number, the thinner and lighter the lens. The Cosmetic & Specialty Tints, High Index Lenses Mid-index lenses, such as 1.54, 1.56, and 1.57, are thinner than glass, and nearly as strong as CR-39. High-
Mid-Index: High index materials are classified by numbers. Again, the higher the number, the thinner and lighter the lens. The lower numbers are classified as mid - Mid-Index: High index materials are classified by numbers. Again, the higher the number, the thinner and lighter the lens. The Mid-Index. Other high index materials are classified by numbers. The higher the number, the thinner and lighter the lens. The
1.57 Mid Index. - Up to 15% thinner than 1.50 lens. - Suitable for full-rim plastic/ acetate or full-rim metal frames. - BEST FOR RX RANGE +2.00/-3.75 OR BELOW. The first step towards clearer vision is learning which lens index is right for you. Our chart explains lens indexes including 1,67 and 1.74 high index lenses.