Material for eyeglass lenses

Applications detail

High-index lenses



With high-impact resistance, high refractive index (R.I.), high Abbe number, and light weight, this thiourethane eyeglass material is the product of our unique polymerization technology.
It is an innovative material for lenses that offer a balanced set of characteristics—thinness, light weight, break resistance, and perfect clarity—demanded by many eyeglass lens users around the world.

Thin and Light

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

mr_fig_01-01 MR™ lens
mr_fig_01-02 Normal lens
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 to use. Thiourethane lenses also exhibit superior processing ability, which means they can be formed into virtually any design.

mr_fig_02-01 MR™ lens
mr_fig_02-02 Normal lens
Lasting Appeal

Thiourethane lenses feature high resistance to wear and resist discoloring over time.
They also allow strong coating adhesion on the lens surface. In effect, the coatings are more resistant to peeling, even after extended use.

Clear View

For plastic lenses, high refractive index and high Abbe number are generally regarded as mutually exclusive properties difficult to achieve in a single lens product. But with our lens material featuring high Abbe number, such as the MR™ 1.60 (MR-8™), we’ve minimized the dispersion of light (chromatic aberration) due to the prism effect, thereby suppressing color fringing.

Precision Eyeglass Lenses

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

Highly-Functional Eyeglass Lenses

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

Fashion-Oriented Eyeglass Lenses

The strength and high workability of MR™ make it ideal for use in fashion-oriented eyeglasses like rimless or high-curved glasses.

A Wide Color Variation for Sunglasses

The high tintability of MR™ makes it ideal for fashion-oriented sunglasses manufactured in a wide range of colors.


Refractive Index 1.60 (MR-8™)

This is the standard high R.I. lens material. Compared to other lens materials of the same refractive index, the exceptionally high Abbe number means minimal chromatic aberration in the visual periphery and an ideal balance of properties such as impact resistance and thermal resistance.


We recommend the R.I. 1.60 MR™ for a wide range of designs and purposes and for optical powers ranging from nearsightedness to presbyopia.

Refractive Index 1.60 (MR-160DG™)

This Do Green™ product is made from plant-derived materials which retaining the optical properties of MR™.


We recommend the R.I. 1.60MR™ for users who are eco-conscious as MR-160DG™ has obtained the biomass mark certification.

Refractive Index 1.67 (MR-7™)

This lineup features a balance of lens thinness, lightness, and high impact resistance. The MR-7™ offers high tintability.


We recommend the R.I. 1.67 MR™ for users who are uncomfortable with thick or heavy high-powered lenses. Since the MR-7™ with its high tintability can be tinted in a short period of time, it is ideal for sunglasses and fashion-oriented glasses.

Refractive Index 1.67 (MR-10™)

This lineup features a balance of lens thinness, lightness, and high impact resistance. The MR-10™ offers superb thermal resistance.


We recommend the R.I. 1.67 MR™ for users who are uncomfortable with thick or heavy high-powered lenses. The heat-resistant MR-10™ lens withstands a wide range of working temperatures and offers added safety for use under challenging temperature conditions.

Refractive Index 1.74 (MR-174™)

This lens material makes it possible to produce ultra-thin lenses of the highest refractive index. Additionally, this Do Green™ product is made using plant-derived materials.


We recommend the R.I. 1.74 MR™ for users looking for the ultimate in thinnes, as well as those who are especially eco-conscious or prefer the highest possible quality.


High Refractive Index

MR™ is available in three different refractive indexes: 1.60, 1.67, and 1.74. Higher R.I. materials makes it possible to manufacture thinner and lighter lenses.

20-40% Thinner

MR-174™-based lens vs. low R.I. lens (-2.00–-7.00D)

mr_fig_04-02 MR-174™-based Lens (R.I. 1.74/-8.00D)
mr_fig_04-03 Low R.I. lens (R.I. 1.50/-8.00D)
20-35% Lighter

MR-7™-based lens vs. low R.I. lens (-2.00–-7.00D)


High Strength

The high impact resistance and static load resistance improve safety for users. The lens material meets the criteria of the US FDA's drop ball test.

FDA Drop Ball Test (lens without coating)

Section 801.410 of the US Food and Drug Administration (FDA) Code of Federal Regulations

mr_fig_06-02 MR-8™-based lens Undamaged
mr_fig_06-03 Medium R.I. lens Damaged
Butterfly test for Rimless Frames

Mitsui Chemicals method based on JIS B7285 (2016) Specification:
breaks at 20,000 strokes (tested by a Japanese lens manufacturer).

mr_fig_02-01 MR-8™-based lens
mr_fig_02-02 Medium R.I. lens


The MR-8™ exhibits high weather resistance. Even after exposure to intense UV light, discoloration is minimal.
It also features high thermal resistance and is highly compatible with coating materials, making the coatings more resistant to cracking and peeling, even under challenging conditions. The lenses maintain viewing clarity for eyeglass wearers even after extended use.

Weather resistance test
mr_fig_08-01 MR-8™-based lens
mr_fig_08-02 Medium R.I. lens (lens yellowing after prolonged use)
Coating peel test

Coating won’t peel off after long-term use.

mr_fig_09-01 MR-8™-based lens
mr_fig_09-02 Medium R.I. lens (peeling of coating is evident)

High Abbe Number

The high R.I. and high Abbe number give the lens optical properties comparable to those of glass lenses.

High Abbe number
mr_fig_11-02 MR-8™-based lens
mr_fig_11-04 Polycarbonate lens
Comparison of distortion through polarized filter
mr_fig_12-01 MR-8™-based lens
mr_fig_12-02 Polycarbonate lens

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