Disadvantages: More expensive. Lens Material Explained- Mid to High Index Plastic Lenses Thin and Lite Prescription Glasses, Lens Material  Mid-Index. Other high index materials are classified by numbers. The higher the number, the thinner and lighter the lens. The  Mid-index lenses, such as 1.54, 1.56, and 1.57, are thinner than glass, and nearly as strong as CR-39. Trivex is an improvement over Polycarbonate. It is lighter 

19 Nov 2013 Mid-index: Slimmer and lighter than basic, these are more compatible with anti- reflective and photochromic treatments. But they may require  16 Oct 2018 But while single-vision lenses with scratch-resistant coating start from $39 with the cheapest frames, High-index lenses are made from special plastic that uses less material to correct a Basic range; Mid-range; Top range. Our high index lens options are supplied with a Hard Anti Reflection coating as Our photochromic lenses are made from a mid index material, 1.56 index,  Comparison of high and mid index lenses with various dioptric powers. All About Lenses Rx Online Optical is your one stop shop for glasses, sunglasses and 

Zenni, as example, sells very high index lenses (1.74) for about 80 USD upgrade cost. If you are already at -2.00 diopters or less, spending the extra money will make no noticeable difference for you. A mid index 1.57 is plenty in this -2.00 diopter scenario.

5 Sep 2011 PURPOSE: The aim was to assess the impact resistance of coated and uncoated mid-index spectacle lens materials using the ballistic impact  Lens index is a number that describes how thick or thin your lenses are. The higher a lens' index is, the thinner it becomes. Higher prescriptions require higher index lenses, while lower prescriptions require lower index lenses. Mid-Index Single Vision Trifocal Lenses contain three focal points, usually for distance, intermediate and near vision. A trifocal lens has an added segment above the bifocal for viewing objects in the intermediate zone, which is approximately arm's length away. Zenni, as example, sells very high index lenses (1.74) for about 80 USD upgrade cost. If you are already at -2.00 diopters or less, spending the extra money will make no noticeable difference for you. A mid index 1.57 is plenty in this -2.00 diopter scenario. The 1.53 mid-index Trivex lens is a polymer lens that is the most impact-resistant lens available. It covers the same range as the 1.57 mid-index lens: -4.00/+2.00 or lower on the SPH and +/- 6.00 or lower on the CYL.

High-index plastics allow for thinner lenses. The lenses may not be lighter, however, due to the increase in density vs. mid- and normal index materials. A disadvantage is that high-index plastic lenses suffer from a much higher level of chromatic aberrations, which can be seen from their lower Abbe value.

Most eyeglass wearers are nearsighted, which requires corrective lenses that are thin in the center but thicker at the edge of the lens. The stronger the prescription,   trivexTrivex lenses are impact resistant lenses and are a lightweight, durable mid -index lens material that is considered an upgrade from its industry-standard  In plus prescriptions, high index lenses will trim down center thickness. This will diminish the look of magnification on your eyes. Features include: Suitable for mid 

It’s the thickest lens that is recommended for prescription with SPH – 2.5, +2.5 and below. To prevent cracking of the lenses, go for full-rimmed frames. The CR 39 lenses are conventional plastic lenses. 1.56 Index – Mid Index Thin and Light Lenses . Convenient lenses for stronger prescription, they are 15% thinner than 1.5 index.

Mid-index lenses are slimmer and lighter than standard plastic types. A variety of protective treatments can also be applied, including photochromic and no-glare  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. 1.57 mid index lens is a base lens, great for full rim frames where the lens is supported on all sides, but is not recommended for semi rimless or rimless frames 

Got your eye on a trendy new glasses frame, but wondering which lens type will suit your needs the best? Fear not, we're here to help with our guide to 

Mid-Index: High index materials are classified by numbers. Again, the higher the number, the thinner and lighter the lens. The  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 lenses, typically ranging from 1.53 to   Mid-Index Plastic: If you require a stronger prescription, you may want mid-index plastic lenses, which are thinner and lighter than standard plastic lenses. Mid & High Index Lenses. In the past, the only materials available for use as lenses were glass and a hard resin called CR-39. The introduction of mid and  It is very strong, very light, and resistant to scratches and breaking. Most sports lenses are made of polycarbonate. Mid-Index Standard Lenses. $48 (mid index 1.56). $68 (high index 1.61). $78 Polycarbonate Impact Resistance. $98 (super high index 1.67). $248 (ultra high index 1.74). Mid-Index. Other high index materials are classified by numbers. The higher the number, the thinner and lighter the lens. The 

Thinner, lighter and more expensive than mid-high index or hard resin lenses, high index lenses are a good choice for every day use. High Index Lenses - 1.70 and 1.74 Ultra High Index. High index lenses with 1.70 high index and 1.74 are the thinnest lenses on the market, and are made only for people with the highest prescriptions. 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. If your diopter number falls between +/- 2.00 and +/- 4.00, the recommended index material is 1.56. Mid-index lenses are slimmer and lighter than standard plastic types. A variety of protective treatments can also be applied, including photochromic and no-glare coatings. Slightly stronger prescriptions for farsightedness typically require a thicker lens. I'm reading on Zenni that 1.61 High-Index Single Vision lenses are recommended. However, those cost an addition $20.00. I don't want to spend an additional $20.00 for a $6.95 pair of eyeglasses. I'd go with the free alternative of 1.57 Mid-Index Single Vision lenses. High-index lenses reflect up to 50 percent more light than conventional glass or plastic lenses. For the best vision and appearance, it's a good idea to have an anti-reflective lens coating (AR coating) applied to high-index lenses. AR-coated high-index lenses transmit up to 99.5 percent of light to the eye for optimum vision. The 1.57 mid-index lens is best for prescriptions +2.00/-3.75 or below. It also features 100% UV protection.