Sep 1, 2023 ... Lenses with a 1.67 index are 33% thinner than 1,5 and enhance the vision for those with a +4.75 to -6.75 prescription requirement. 1.74 index ...Thickness difference between the two indexes will be negligent but the weight of the lenses will be noticeable. If your wallet permits , spring for the 1.67 index lenses . My extra is not nearly as high as yours and I prefer 1.74 index lenses simply for their weight .Suitability for High Prescriptions. For those with higher prescriptions, 1.67 high-index lenses are often recommended due to their ability to bend light more efficiently, resulting in a thinner lens. Trivex, while not as thin, still offers a lightweight solution with added durability.Jul 7, 2022 · 1. Trivex lenses have an index of 1.53 which is lower than high index plastic having 1.67 to 1.74. The higher the index, the more lightweight and thinner the lens will be. 2. In terms of resistance to scratch, both lenses are the same. 3. Trivex lenses are more impact resistant than high index lenses.Both 1.67 and 1.74 high-index lenses can accommodate strong prescriptions. The difference is in the thickness. 1.74 high-index lenses are up to 10% thinner than 1.67 high-index lenses. As a reference, 1.67 high-index lenses are recommended for strong prescription with an SPH correction between +/-7.00 and +/ …방문 중인 사이트에서 설명을 제공하지 않습니다.A 3.67 GPA is equal to an “A” letter grade or being in the 91st or 92nd percentile. GPA stands for “grade point average” and represents the average grade of all the coursework a st...We firmly believe the prices of our prescription lenses offer the best value when compared with other online retailers and high street opticians - see for yourself below. Lens Guide ... High Impact (1.56 Index) - Clear Lenses. $116.67. 1.59 D28 Polycarbonate - Clear Lenses. $83.33. 1.60 D28 Flat Top - Clear Lenses. $166.67 + Tints.In your case though, I wouldn't recommend it. While I would also recommend 1.74 hi index for your Rx strength, having the ability to make adjustments and such needed is going to make a world of a difference for you. In your case, having your eyes centered on the lens is going to be more important than for someone with a …ZEISS Single Vision SmartLife lenses. Supported by ZEISS SmartView Technology, based on applied research of today’s lifestyle, visual behaviour and individual age-related visual needs. The first ZEISS single vision lenses optimised for both distance and near vision. Available in: Plastic 1.5, Plastic 1.6, Plastic 1.67, Plastic 1.74, Trivex 1.53.Our 1.74 high index lenses are offered at a more affordable price with a long list of value adds: anti-scratch, and 100% UV protection. Available at $69.95. Our 1.74 high index digital free form lenses use leading technologies in the eyeglasses market. Now at $79.95. Our 1.74 digital free form progressive (no-line, multi-focal) lenses …Feb 26, 2020 ... Generally speaking, high-index is best suited for higher (more severe) prescriptions. Anything above a minus 5 and above a plus 3 is considered ...1.67 High Index Lenses are typically 35% thinner than ordinary CR39 plastic. 1.74 High Index Lenses are normally 50% thinner than ordinary CR39 plastic. High-index lenses can improve lens comfort and appearance, and may even open the entranceway to a larger variety of frames. High-index lenses may be just the answer you have been searching for.Sep 12, 2023 · BY Dr. Sophia Moh. IN Lenses. Sep 12, 2023. High index lenses have revolutionized the world of eyewear. But what exactly are they? High index lenses (1.61, 1,67, 1.74) are lenses that are made from materials with a higher refractive index than traditional lenses (1.50 Standard Index). Are you a classic car enthusiast in search of the iconic 67 Chevelle? Look no further. In this ultimate guide, we will provide you with valuable tips and tricks to help you find th...Both 1.67 and 1.74 high-index lenses can accommodate strong prescriptions. The difference is in the thickness. 1.74 high-index lenses are up to 10% thinner than 1.67 high-index lenses. As a reference, 1.67 high-index lenses are recommended for strong prescription with an SPH correction between +/-7.00 and +/ …The difference in thickness is less than 1mm. Better to size down slightly in the frame to decrease thickness. At nearly any frame size with your RX, the thickness difference will be negligible. Probably around .5 mm at the very thickest point, nearly impossible to see. The optics out of a 1.67 lens is much better than 1.74.The main difference I noticed, though is the 1.59 vs 1.67 index. KITS Premium, which is "High quality 1.59 index lens". KITS Premium Impact Resistant, which I believe is the the same as previous except it is polycarbonate. This is 1.59 index also. $10 extra. KITS Premium Feather Light, which is 1.67 index for $49 extra.Here are the recommendation. If your power is around -2.00, choose 1.56 index, it will be around 3mm. For power around -4.00, choose 1.61 index, it will be around 3 to 4mm. If your power is around -6.00, choose 1.67 index , it will be around 4 to 5mm. For power more than that, choose the thinnest lens, 1.74 index. It will be around 5mm to 8mm.High Index Plastic: 1.60: 36: High Index Plastic: 1.66: 32: Trivex: 1.53: 43: Polycarbonate: 1.58: 30: MR-174 1.74 32. Chromatic aberration is when white light is broken up into component colors. A color fringe may be noted around a light source or around an object. In reality ...3 days ago · Birefringence is a measurement of the difference between the two refractive indices in gems that are doubly refractive, and it ranges from a low of .003 to a high of .287. The following chart lists the refractive indices for 215 varieties of gemstones. Refractive Index Chart of all Gemstones GemstoneIn this section, we will show you the differences between 1.67 high index lenses and 1.74 high indexes. 74 high index lenses are thinner and lighter than 1.67 high index lenses. 74 high index lenses are expensive than the 1.67 high index lenses. Both 1.67 and 1.74 high index lenses can reduce the eye distortion caused by strong …Feb 27, 2019 · With free-form lenses (also called digital high-definition lenses), the fabrication of the lenses from wearer's eyeglass prescription is optimized with computer-controlled surfacing equipment that is much more precise than conventional tools.. In fact, free-form technology can surface lenses in power increments of 0.01 diopter (D), …The 1.61 High-Index is an extra $35, and sounds more brittle and less scratch resistant. Prescription L: -1.25 sph, -0.75 cyl, 180 axis R: -1.75 sph, -0.75 cyl, 180 axis I also saw one old comment claiming "1.56 is a s*** material that you will usually only find at cheap online retailers" - not sure if true. Thanks ... Most polycarbonate lenses have a refractive index of 1.59. This figure means that they can be around 10 percent thinner than other lenses, including glass. By contrast, 1.67 high-index lenses are about 30 percent thinner and lighter, and 1.74 single-vision lenses are 35 percent thinner for the same prescription strength. 1.6 Vs 1.59 Lenses. Today we’ll be talking specifically concerning the range between 1.59 and 1.67, neither the lowest nor the best of the high index lenses and therefore where most lens shoppers will find themselves. These stylish, super-thin lenses are excellent choices for people who have strong prescriptions or particularly thin …Edit2, seems like trivex 1.53 is still clearer than the 1.57 zenni offers according to their Lens Index & Material Guide, but it still doesn’t tell me what the 1.57 is made of, they only specify trivex fo 1.53, CR39 for 1.5, polycarbonate for 1.59 and everything high index is “MR”Most polycarbonate lenses have a refractive index of 1.59. This figure means that they can be around 10 percent thinner than other lenses, including glass. By contrast, 1.67 high-index lenses are about 30 percent thinner and lighter, and 1.74 single-vision lenses are 35 percent thinner for the same prescription strength. Sort by: InverseMeters. • 4 yr. ago. Frame size and shape is going to have a bigger effect on thickness than index. The difference between 1.60 and 1.67 is going to be minimal, most likely less than a millimeter. 1.67 will cost more and have more abberations. Unless the frame is huge and your eyes are narrow set 1.60 would most likely better. May 31, 2023 ... Because they are typically processed to be as thin as possible, and because high index is a plastic that will crack when enough force is applied ... Generally, lenses with an increased index of refraction will be thinner than lenses with less index. The refractive index of high index plastic lenses ranges from 1.53 to 1 1.74. Those in the range of 1 1.53 to at least one 1.59 are about 20% thinner than regular plastic lenses, whereas 1.74 high index lenses… Measurements of lens flatness (base curve) on 1.60 ZEISS ClearView FSV lenses compared to ZEISS SPH FSV lenses over a range of prescriptions (-5D, -3D, -1D, +1D, +3D, +5D with and without cyl -2D). Maximum reduction of 49 % of -5.00D with and without cyl -2D. Quantitative analyses by Technology & Innovation, Carl Zeiss Vision GmbH, 2020.Feb 22, 2023 · There are a number of different lens index lenses available, with some better suited to certain prescriptions than others. You’ll generally find lens index in the following sizes: 1.5 Standard. 1.56 Mix-Index. 1.57 Thin and Light Index. 1.59 Standard Polycarbonate and High Index. 1.74 High Index Lenses are the thinnest and lightest. High Index Plastic: 1.60: 36: High Index Plastic: 1.66: 32: Trivex: 1.53: 43: Polycarbonate: 1.58: 30: MR-174 1.74 32. Chromatic aberration is when white light is broken up into component colors. A color fringe may be noted around a light source or around an object. In reality ... Certain high index materials are available with the coating, but the nature of high index lenses often precludes the availability of transitional lenses. Not all manufacturers combine the two formats – especially on the higher-end high index materials like 1.80 or 1.90 glass lenses. If you want transition high index lenses you’re more ... Also, no such thing as 1.5 polycarbonate. It's either CR39 1.5 index (very good material) or polycarbonate (1.59 index, worst possible material for optical clarity) Standard 1.5 is sufficient. If you want the lenses really thinned (depending on the frame choice). 1.6 is better.Hi, I've decided to go for the cheap approach of getting lens with Zenni for my headset. When I selected the lens I was asked if I wanted to put blue light and UV block (Blokz) among other choices. At first, I was like "Hell yeah, protect my eyes from this demonic blue light !" but then I started to wonder if this would affect my …1.61 vs. 1.67 vs. 1.74 High Index Lenses. 1.61 High Index Lenses. Moderate Prescription Strengths: Ideal for those with mild prescriptions (less than +/- …방문 중인 사이트에서 설명을 제공하지 않습니다.Polycarbonate Lenses: Pros & Cons. Polycarbonate lenses are 10 times stronger than glass or traditional plastic lenses. Best of all, this strength doesn’t affect their weight. The lenses are extremely light and comfortable to wear for long periods of time. They are also much less likely to shatter and cause eye injury, making them an ideal ... Edit2, seems like trivex 1.53 is still clearer than the 1.57 zenni offers according to their Lens Index & Material Guide, but it still doesn’t tell me what the 1.57 is made of, they only specify trivex fo 1.53, CR39 for 1.5, polycarbonate for 1.59 and everything high index is “MR” ZEISS Single Vision AS 1.67 is an extremely thin single vision lens in the range of plastic lenses available from ZEISS. It is extremely light and a very special lens in many ways. In 1997 ZEISS was Europe’s first manufacturer to succeed in polymerizing a plastic lens with the super-high index 1.665 for batch production.Versus the 1.6 lens could be more optically clear, but will undoubtedly be heavier and not impact resistant . The thinnest option available and designed for people that have the best prescriptions, 1.74 high index lenses are the optimal choice should you have a high prescription. 1.67 high index lenses are incredibly thin and light, …High index lenses are thinner, lighter, and more appealing than standard lenses, but they come in several different indexes.. If you’re shopping for high index lenses and aren’t sure whether to go for 1.67 or 1.74, we have some information that might help you with your decision.. The main differences between these two lenses are …Nov 12, 2020 ... Uncut Glasses Side Thickness Compare 1.56 vs 1.60 vs 1.74 | Crizal 1.74 Lenses | High Index Lenses.High Index "necessary" for these kinds of frames? I've been trying to find semi-large circular lenses to little success, though I did find one pair that I actually liked. However I'm worried that my high prescription (-5.50 right, -5.25 left) might benefit more from a higher index. (1.61 vs 1.67). Though that makes the lenses about …Mar 19, 2024 · Assuming that light travels from air to glass, the angle of incidence is 30°, and the angle of refraction is 20°. To calculate the refractive index, follow these steps: Identify the refractive index of air: n ₁ = 1. Modify Snell's law to find the refractive index of glass: n ₂ = n ₁sin (θ₁)/sin (θ₂). Enter data: n ₂ = 1×sin (30 ...1.61 vs. 1.67 vs. 1.74 High Index Lenses. 1.61 High Index Lenses. Moderate Prescription Strengths: Ideal for those with mild prescriptions (less than +/- …Feb 26, 2020 · High-index materials are denser than lower-index polycarbonate, which means they result in thinner lenses in order to refract light accurately. For example, if a polycarbonate lens requires 2 millimeters of material to refract light, high-index may only need 1 millimeter. Translation: high-index is the smart option for stronger prescriptions. Dec 6, 2021 · In this section, we will show you the differences between 1.67 high index lenses and 1.74 high indexes. 74 high index lenses are thinner and lighter than 1.67 high index lenses. 74 high index lenses are expensive than the 1.67 high index lenses. Both 1.67 and 1.74 high index lenses can reduce the eye distortion caused by strong prescriptions, 1 ... Thinner and lighter than our basic lenses, high-index lenses are recommended for those with combined Rx powers over -3.00/+2.00. High-index lenses have reduced edge thickness for nearsightedness and reduced center thickness for farsightedness. Choose from 1.61, 1.67 or 1.74 high index lenses. All Zenni high-index lenses are made with MR™, a ... A 3.67 GPA is equal to an “A” letter grade or being in the 91st or 92nd percentile. GPA stands for “grade point average” and represents the average grade of all the coursework a st...Jul 4, 2020 ... If u want to make these type of spectacles then whatsapp your power and Contact through whatsapp 9818540760. Link to watch special videos ...방문 중인 사이트에서 설명을 제공하지 않습니다.Feb 19, 2021 · Zenni Optical offers three types of high index lenses: 1.61 at an additional cost of $19.95. 1.67 at an additional cost of $34.95. 1.74 at $74.95. So, if you need the high index lenses, you’re ...I have a +4.25 prescription, should I get 1.67 or 1.74 index lenses for glasses? Would there be any noticeable difference in thickness? I'm also concerned about the distortion/warping - my current pair is just a standard lens (not high-index) and there is a noticeable warping effect when looking at my eyes from a side angle, I think this is due to how thick the … A 1.67 high-index lens is best for +7.00/-9.00 or above. It can even be a good choice for people with low prescriptions who want the additional lens benefits mentioned above. If you have a prescription that is +4.25/-6.75 or below, you’ll benefit from the thinness of a 1.61 high index lens. 1.74 Strong Index. Do you know the differentiation between various lens flash? Go this article to learn more about books of refraction measurements for my eyeglasses. x Blue Light Blocking Glassware BOGO 40% OFF BOGO 40% OFF. WOMEN. Women's Glass. All Women's Glasses. Cat-Eye Eyeglasses. New Arrivals. Best Sellers. $5. ... High index lenses bend light more effectively than other types of lenses because of their higher index of refraction, so Lensmart offers 1.61, 1.67 and 1.74 high index lenses. You can easily find the best frame for lenses and enjoy the perfect fit. With lightweight high index lenses, you can have clear vision without the "coke bottle" look. One of my eyes is worse than the other (-0.25 vs +2.00) and in that eye, you can tell looks slightly bigger and "buggier" through that lens and it makes me self-conscious. I currently have 1.61 high index lenses, and am wondering if moving up to 1.67 would have any noticable affect on my eye size? Negligible difference to the average person? Our 1.74 high index lenses are offered at a more affordable price with a long list of value adds: anti-scratch, and 100% UV protection. Available at $69.95. Our 1.74 high index digital free form lenses use leading technologies in the eyeglasses market. Now at $79.95. Our 1.74 digital free form progressive (no-line, multi-focal) lenses …Feb 20, 2024 · 1.67 index lenses are suitable for prescriptions under +5.00/-8.00 and astigmatism correction between -3.00 and -4.00. 1.74 index lenses are the thinnest high-index lenses. This lens is suitable for stronger prescriptions above +5.00/-8.00 and astigmatism correction between -4.00 and -6.00. May 18, 2023 ... Standard lenses are at an index of 1.50 while the highest options are between 1.74 and 1.90. The stronger your prescription, you can choose ...We firmly believe the prices of our prescription lenses offer the best value when compared with other online retailers and high street opticians - see for yourself below. Lens Guide ... High Impact (1.56 Index) - Clear Lenses. $116.67. 1.59 D28 Polycarbonate - Clear Lenses. $83.33. 1.60 D28 Flat Top - Clear Lenses. $166.67 + Tints. Generally, lenses with an increased index of refraction will be thinner than lenses with less index. The refractive index of high index plastic lenses ranges from 1.53 to 1 1.74. Those in the range of 1 1.53 to at least one 1.59 are about 20% thinner than regular plastic lenses, whereas 1.74 high index lenses… Jun 30, 2021 · High index lenses have a refractive index of 1.53–1.74. Polycarbonate, which has a refractive index of 1.59, offers a mix of strength and thinness. Many companies offer polycarbonate lenses for ... The difference between 1.60 and 1.67 is going to be minimal, most likely less than a millimeter. 1.67 will cost more and have more abberations. Unless the frame is huge and …Jun 29, 2022 · The difference is in the thickness. 1.74 high-index lenses are up to 10% thinner than 1.67 high-index lenses. As a reference, 1.67 high-index lenses are recommended for strong prescription with an SPH correction between +/-7.00 and +/-9.00, and a CYL correction between +/-3.25 and +/-4.00. 1.74 high index lenses are known “as thin as possible ... The most affordable of the higher Index lenses and very tough compared to CR39. As this material is around 15% thinner and 20% lighter than the 1.5 it offers an ... Thinner and lighter than our basic lenses, high-index lenses are recommended for those with combined Rx powers over -3.00/+2.00. High-index lenses have reduced edge thickness for nearsightedness and reduced center thickness for farsightedness. Choose from 1.61, 1.67 or 1.74 high index lenses. All Zenni high-index lenses are made with MR™, a ... Buy High Index Lenses. Trivex has a low index of 1.53, similar to standard plastic. High index plastic’s index ranges from 1.67 to 1.74, making it considerably thinner and more lightweight than Trivex, especially in higher prescriptions. High index plastic has similar scratch resistance to Trivex.This guide discusses everything you need to know concerning the lens index and 1.57 mid index lenses, including standard or mid-index lenses, high index lenses vs. polycarbonate, and much more. 1.61 high-index lenses offer an ultra-thin option for all those looking for a modern, stylish look.We use FIB-4 as an initial assessment. In chronic HCV, when combined with APRI, it has excellent negative predictive value for excluding advanced fibrosis. The positive predictive value is less clear. Those with FIB-4 >1.5 and/or APRI >0.5 often go on to liver elastography. There are no data on the use of FIB-4 in someone who has been treated ...In today’s digital age, researchers rely heavily on various tools and databases to enhance their work. One such tool that has gained immense popularity among scholars is the Scopus...When it comes to choosing the perfect refrigerator for your kitchen, size plays a crucial role. The dimensions of a refrigerator can impact its functionality and how well it fits i...Dialing *67 directly before dialing a phone number deactivates caller identification, or caller ID, and the caller ID of the person you are calling will read “private number” inste...Dec 14, 2022 · Standard polycarbonate lenses can range in price from $9 to $205, depending on your prescription and what add-ons you choose, including whether you need standard, bifocals, or progressives. Trivex lenses, in contrast, start around $200 for single-vision lenses. Progressive lenses for multifocal vision needs are $400 to start.Versus the 1.6 lens could be more optically clear, but will undoubtedly be heavier and not impact resistant . The thinnest option available and designed for people that have the best prescriptions, 1.74 high index lenses are the optimal choice should you have a high prescription. 1.67 high index lenses are incredibly thin and light, …It’s always tempting to ignore your phone when the caller ID reads “Unknown Number” — you don’t want to gamble on answering a call from a telemarketer or a prankster. Even people i...
The prime numbers less than 100 are: 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89 and 97. A prime number is any number that is only di.... Hey fiesta
Most polycarbonate lenses have a refractive index of 1.59. This figure means that they can be around 10 percent thinner than other lenses, including glass. By contrast, 1.67 high-index lenses are about 30 percent thinner and lighter, and 1.74 single-vision lenses are 35 percent thinner for the same prescription strength.Refractive Index 1.60 MR-8™/MR-160DG™. This lineup is standard high R.I. lens materials. MR-8™ has a high abbe number, means minimal chromatic aberration in the visual periphery. and an ideal balance of properties such as impact resistance and thermal resistance. MR-160DG™ is made from plant-derived lens materials …There are a few other key differences between the strengths of high index lenses. One is the cost: 1.74 lenses can be significantly more expensive than their 1.67 brethren. Perhaps because of this, and the corresponding higher demand for 1.67s, there are more options available for the 1.67s. There are often more colors available for sunglasses ...I'm buying glasses for the first time from Zenni and 1.74 high index lenses are recommended for my prescription (-12.50/-13.25). They also have UV/blue light blocking lenses they call Blokz, but they only come in a 1.67 high index lens. I get migraines at least once every week or two and become sensitive to light during …Sep 12, 2023 · BY Dr. Sophia Moh. IN Lenses. Sep 12, 2023. High index lenses have revolutionized the world of eyewear. But what exactly are they? High index lenses (1.61, 1,67, 1.74) are lenses that are made from materials with a higher refractive index than traditional lenses (1.50 Standard Index). Craft breweries have gained immense popularity in recent years, offering beer enthusiasts a wide range of unique and flavorful options. One such brewery that stands out from the cr...Feb 4, 2022 ... Hi there! Thanks for checking out my video, I hope it helped. I've been glassy since I was young and so I know how important it is to choose ... High index lenses bend light more effectively than other types of lenses because of their higher index of refraction, so Lensmart offers 1.61, 1.67 and 1.74 high index lenses. You can easily find the best frame for lenses and enjoy the perfect fit. With lightweight high index lenses, you can have clear vision without the "coke bottle" look. Polycarbonate lenses have an index of refraction of 1.59, and will generally be about 20% thinner than standard plastic lenses. Polycarbonate lenses also provide you with protection from 100% of the harmful UV rays from the sun. I generally recommended people with prescriptions anywhere between +/-0.50 to +/-4.00 to go with …3 days ago · Birefringence is a measurement of the difference between the two refractive indices in gems that are doubly refractive, and it ranges from a low of .003 to a high of .287. The following chart lists the refractive indices for 215 varieties of gemstones. Refractive Index Chart of all Gemstones GemstoneZEISS Single Vision SmartLife lenses. Supported by ZEISS SmartView Technology, based on applied research of today’s lifestyle, visual behaviour and individual age-related visual needs. The first ZEISS single vision lenses optimised for both distance and near vision. Available in: Plastic 1.5, Plastic 1.6, Plastic 1.67, Plastic 1.74, Trivex 1.53. OD: -2.50 -0.75 * 178. OS: -4.25 -1.25 * 005. The optometrist suggested that I pick between 1.61 and 1.67, so I purchased 1.67 Zeiss AS DP lenses for 49 []21 glasses since I figured that the thinner the better... was this overkill? After I got home I'm reading through ABBE values and eye strain due to higher index lenses and I'm getting cold feet. As of this review, there are over 800 options for Men, over 1,100 options for Women, just under 100 options for Boys, and over 100 options for Girls. Pricing is all over the place depending on the desirability and material of the frames, but the prices start as low as $6.95 and go as high as $45.95 (that’s the most …Feb 4, 2022 ... Hi there! Thanks for checking out my video, I hope it helped. I've been glassy since I was young and so I know how important it is to choose ... A 1.67 high-index lens is best for +7.00/-9.00 or above. It can even be a good choice for people with low prescriptions who want the additional lens benefits mentioned above. If you have a prescription that is +4.25/-6.75 or below, you’ll benefit from the thinness of a 1.61 high index lens. 1.74 Strong Index. It really depends on the size of the frame you want to buy. Smaller frames will show less of a difference between the two materials, and with a larger frame you will see a difference. 1.74 has a crappy Abbe value and produces visual distortion. Also, 1.74 is actually thicker than 1.67. 1.67 is better overall.Sep 10, 2018 ... ... 1.61 - Reco. power -5.00 to -8.00 4. 1.67 ... High index lenses 1.56 Vs 1.74 | -5.50 Power | High Index Glasses ... index Lenses | -14.00 | High ...The index of refraction of the coating material is 1.41 and the index of the glass is 1.66. What is the minimum thickness of coating which should be placed on a lens in order to minimize reflection of 636 nm light? The index of refraction of the coating material is 1.41 and the index of the glass is 1.66. There are 2 steps to solve this one.1.67 High Index. The 1.67 High-Index lenses are 30% thinner than 1.50 Standard Index lenses with the same prescription. For higher prescriptions, this lens material and index works well due to its reduced weight and edge thickness. 1.74 High Index. 1.74 High-Index lenses are the thinnest and lightest lenses you can buy from …High index lenses have a refractive index of 1.53–1.74. Polycarbonate, which has a refractive index of 1.59, offers a mix of strength and thinness. Many companies offer polycarbonate lenses for ....