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High index lenses are glasses lenses that are thinner and lighter than standard options. They may benefit people with stronger prescriptions who might otherwise have heavier, thicker lenses.
An estimated 150 million people in the United States have a refractive error. The four most common types of refractive error are astigmatism, nearsightedness, farsightedness, and age-related farsightedness.
People with refractive errors often require stronger prescriptions. They may therefore benefit from using high index lenses.
In this article, learn more about high index lenses, what to consider when choosing them, and where to purchase them.
Glasses and contact lens prescriptions contain different numbers and abbreviations. When looking at a prescription, a person will likely notice the following information:
Displayed after each of these letters will be a numerical value with either a plus (+) or minus (-) sign. The higher the number, the more correction a person’s eye needs. The plus sign indicates that a person has farsightedness, and the minus sign indicates that a person has nearsightedness.
If a person’s eye has an unusual curve, values are added for cylinder (CYL) and axis.
The eye is usually spherical, but a new curve can develop and change the eye shape. The CYL indicates how much curve is present. The axis indicates where the curve appears on the eye.
A person may need similar corrections in both eyes or different corrections in each eye.
High index lenses are made using a type of plastic that bends light more efficiently than other common types of lenses. The result is a lighter, thinner lens that more easily fits inside regular frames.
If a person’s eyesight prescription shows a higher number after the plus or minus sign, they have what experts call a strong prescription, which typically also means that they have thicker, heavier glasses lenses that need a more durable frame. This can restrict a person’s choice when looking to purchase new glasses.
High index corrective lenses bend light more efficiently than standard lenses, allowing for a thinner, lighter lens option. This makes it easier to fit them inside regular frames and opens up a wider selection of glasses.
Those with a weaker prescription can also purchase high index lenses, as they are often lighter than traditional lenses.
The table below shows a comparison between standard lenses and high index lenses.
Potential advantages of high index glasses include the following:
The following are some disadvantages of high index glasses:
All glasses lenses work by bending light, and how quickly the light travels through the lens is known as the refractive index.
The refractive index generally defines the type of high index lens a person has. Plastic lenses, known as CR-39, have a refractive index of 1.5. 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 an additional fee.
Lenses that are 1.74 are the thinnest lenses a person can purchase. Typically, only people with very high prescriptions use these. They are often the most expensive option.
Not everyone needs high index lenses, and some online retailers discourage people with prescriptions of less than +/-6.00 from purchasing lenses that are 1.74.
Some factors that a person may like to consider before purchasing expensive high index upgrades include:
The following are some online retailers offering high index lens options.
GlassesUSA offers several different frame and color options, including ones from brand-name designers. In addition to glasses, it can also fulfill contact lens prescriptions. Its thinnest lens goes up to 1.67.
Other features and services include:
EyeBuyDirect offers a large selection of frames to accommodate prescription and nonprescription lenses. A person can choose their frames, color, and any added features for their lenses.
Lensabl offers several brand-name frames and styles of eyewear. In addition, it offers 1.67 and 1.74 high index options for prescriptions over +/-4.00.
Pair Eyewear is a boutique glasses shop that primarily caters to children. The majority of its lenses are polycarbonate with added scratch-resistant, UV, and antireflective coatings at no extra charge.
Pair Eyewear also accepts HSA and FSA payments.
Payne Glasses can accommodate high index lenses up to 1.74. It offers a variety of different style frames and colors.
Each of its lens options can also include extras such as transitions, which react to different lighting levels, and coatings, which help protect the lenses.
Some additional features and services include:
Like glasses, contact lenses can accommodate higher prescriptions. The American Optometric Association says that a person may prefer contact lenses for the following reasons:
However, when using contact lenses, there are safety considerations to make. To protect the contact lenses and one’s eyesight, the Centers for Disease Control and Prevention (CDC) recommend that a person:
Below, we answer some commonly asked questions about high index lenses.
Generally, people with stronger prescriptions may benefit more from high index lenses. High index lenses are thinner than regular lenses, which may decrease the weight of the glasses and avoid making eyes look smaller.
A person should always discuss which lenses are most suitable with an optician.
High index lenses cost more than regular lenses due to the materials they contain.
Manufacturers usually make high index lenses from polyurethane resin, which costs more to produce than regular lenses.
There is no standard weight for high index lenses.
Different manufacturers may offer different weights. The prescription strength of the glasses may also affect the weight.
Eyeglass companies state that most high index lenses offer nearly 100% UV protection.
However, people should discuss whether they will need to purchase UV coatings for their lenses with an optician.
High index lenses are thinner than regular lenses, so they should not make a person’s eyes look smaller.
High index lenses are lighter and thinner than traditional lenses. They can be a good choice for people with stronger glasses prescriptions.
Some disadvantages include added costs.
A person with a lower prescription may find that polycarbonate lenses offer a sturdy, thinner option that is better for those who are very physically active.
Last medically reviewed on June 30, 2021
GlassesUSA is an online company offering eyeglasses, sunglasses, and contact lenses. Find out more about the brand, reviews, and eye care here.
Lensabl offer a range of eyewear products and services for purchase online, including contact lenses, glasses, and lens replacements. Learn more about…
Payne Glasses offers many glasses frame and lens options online. Learn about the company and tips for glasses shopping and eye care here.
EyeBuyDirect offer a range of glasses and sunglasses for purchase online. They also offer prescription and blue light lenses. Learn about EyeBuyDirect…
Polycarbonate Sv A person can get their glasses prescription from their doctor's office. It is also possible to use an online service, but these are not suitable for…