Lighter, Stronger, Clearer Eyeglasses
MR™ is the de facto standard brand of high R.I. lenses
currently advancing the evolution of eye care.

Eyeglasses need to provide numerous characteristics, among them clarity, safety, durability, and refractive index.
The industry has long sought an innovative material that offers these properties in a balanced way.
MR™ lens materials are made from thiourethane resin, a material not yet widely used for lenses.
Thiourethane realizes lens properties not available from other materials.
That’s why it’s been eagerly adopted by eyeglass makers around the world.

When ordering lens materials,
look for the MR™ trademark printed
on the lens package or envelope
or check with your supplier
to confirm you’re getting MR™ lenses.

Properties of MR™

Thin and Light

Lenses generally become thicker and heavier as optical power increases. But with the development of high R.I. lens materials, it’s now possible to make thinner, lighter lenses.
Now, even high-power lenses can be made thin and comfortable to wear.

Safe and Resistant to Breakage

The toughness of thiourethane resin makes it possible to build thin eyeglass lenses with high impact resistance. Thiourethane lenses resist breaking and chipping, even for two-point or rimless glasses, making them safer to wear and use. Thiourethane lenses also exhibit superior workability, which means they can be formed into virtually any design.

Lasting Appeal

Thiourethane lenses feature high wear resistance and resist discoloring over time.
They also allow stronger adhesion of the coating material to the surface. The coatings are more resistant to peeling, even after extended use.

Clear Views

Due to the prism effect, which disperses light passing through a lens, color fringing (chromatic aberration) typically becomes more evident in the view as the optical power of a lens increases.
Lens materials with high Abbe numbers,* like MR-8™, can minimize chromatic aberration.

*The Abbe number is an index associated with chromatic aberration.

Click here for a video showing the experiment comparing lenses

MR™: Advancing eyeglass lenses to a whole new level

Enabling More Precise Lens Designs

Due to the high workability of thiourethane MR™, it’s ideal for use in lenses that require precise design.

Lens suited for MR™

Progressive lens

Unlike monofocal lenses, which are made to a single optical power, a progressive lens has a seamless and continuous progression of optical powers. If users experience difficulty in viewing objects both near and far due to presbyopia, a single pair of glasses can provide comfortable coverage of points at all distances.

Aspherical lens

The common spherical lens tends to produce distortions in the visual periphery. An aspherical lens, on the other hand, has specially-curved surfaces to reduce distortion.


Easier Manufacturing of Highly Functional Lenses

MR™ is manufactured from a unique monomer polymerization process that make it possible to add functions like control of specific wavelengths or photochromic properties by blending special dyes. Highly compatible with coating materials and film, the material also makes it easier to manufacture highly functional polarized lenses.

MR™-based functional lens materials

For optical health care
UV+420cut™
Photochromic lens
SunSensors™
For enhanced viewing
NeoContrast™

The Birth of MR™: A History of Eyeglass Lenses and Refractive Index

The first plastic lenses for eyeglasses were produced in the 1940s. A material called ADC* dominated the market for quite some time as an alternative to glass.
ADC lenses had several disadvantages, including low refractive index, and tended to be thick and cosmetically unappealing. This led to demand for a high refractive index material that would allow thinner lenses. Later, plastic materials such as acrylic and polycarbonate entered widespread use as medium refractive index materials for eyeglass lenses. Nevertheless, various issues remained, including toughness and chromatic aberration.
In the 1980s, Mitsui Chemicals drew on urethane resin, which exhibited superior impact resistance, as an eyeglass lens material. It introduced sulfur atoms to improve refractive index in its development of a material based on a new concept called the thiourethane lens. In 1987, Mitsui Chemicals produced MR-6™, the first in a line of MR™ brand products. This optical lens material was based on an innovative molecular structure that achieved a refractive index of 1.60, high Abbe numbers, and low specific gravity, paving the way to a new age of high R.I. lenses.

Chemical structure of MR-6™

Developments in 1991 led to a lens material with an even higher refractive index of 1.67, the MR-7TM followed in 1998 by the MR-8™, with refractive index of 1.60 and improved Abbe number compared to the MR-6™. The MR-174™ announced in 2000 exhibited a record-high refractive index of 1.74, allowing opticians to provide lenses of unprecedented thinness, even for higher-powered corrective lenses.

History of Refractive Index of Eyeglasses

*ADC: Allyl diglycol carbonate

Lens Makers Who Have Adopted MR™

MRTM lenses have been manufactured by a number of lens makers around the world, including the following: