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- 27. What tasks does your job entail? Do you use a computer? Does your job or hobby have the potential to cause injury to your eyes? Then get specific.
- 28. Do you work in fluorescent lighting? Do you work in low lighting? Does your safety depend on clear, crisp vision? Do you work with color?
- 29. Do your hobbies involve sports or athletic equipment? Do you spend a lot of time outdoors? Do you work with chemicals? Do you work with tools, such as hammers, saws, grinders, etc.
- 30. Wouldn’t lightweight eyewear be more comfortable? Wouldn’t your high prescription look better in a thinner lens? Wouldn’t you like to wear the latest styles in frames?
- 31. Wouldn’t you like to prevent damage to your eyes from the sun? Wouldn’t you enjoy eyewear that is comfortable on your nose? Wouldn’t you like to wear the latest in lens technology?
Editor's Notes
- Introduction Ophthalmic lens technology has made major advancements over the past 20 years. This course gives an overview of the development, features, benefits and properties of Trivex material and how it is used in ophthalmic lenses. Learning Objectives Upon completion of this course, the participant should be able to: give an overview of the development of Trivex material; summarize the features and properties of Trivex; explain the features and benefits of Trivex; list some of the uses of Trivex; give an overview of how to work with Trivex in the lab; list some dispensing tips.
- The optical industry has seen a drastic evolution of ophthalmic lens materials over the centuries.In A.D. 60, Nero watched gladiator games through his emerald lenses. In 1456, the printing press was invented and made reading glasses practically a must. In 1784, the bifocal was invented. In 1828, the first concave cylindrical lens was developed. Bausch and Lomb presented the first factory-produced ophthalmic glass in the U.S. in 1916. CR-39, the “space age polymer”, was first used in ophthalmic lenses in 1962 In the early 1980s, polycarbonate was introduced by Gentex Corporation. High Index 1.60 was introduced in 1987, 1.66 in 1992 and 1.74 in 2005.
- Since the introduction of CR-39, general market conditions grew toward lighter and thinner lenses, which are generally represented by higher index lens materials. So, in the early 1980s, polycarbonate was introduced by Gentex Corporation. With an index of refraction of 1.59, polycarbonate lenses were the lightest and thinnest available at the time. Their impact resistance made them the lens of choice for children and other eyeglass wearers who were at risk of breaking lenses. They were also recommended for those with one eye or older people who may stumble and fall.
- Although polycarbonate was very reliable in its UV protection and strength, it was was not tintable and not a good choice for dark sunglasses. It had hardcoat on both sides. It was tintable to only about a medium density. Then, tintable polycarbonate became available with coating only on the front. Now polycarbonate can be tinted to a sunglass shade
- Polycarbonate has always had an outstanding reputation as a high impact lens material. It a thermoplastic often referred to as a “plastic metal” due to its strength-to-weight ratio. Lenses are made by injecting heated granules into stainless steel molds which undergo great pressure to form a lens. The lenses are then fully finished or finished on the front and are ready to be surfaced on the back for custom prescriptions. Compression of the monomer in the manufacture of polycarbonate makes the final product flexible under impact.
- The traditional benefit of glass lenses is the quality and stability of the optics. Glass is also a desirable choice for precision optics. However, glass had only one of the desired features: optical quality. It was not thin or light, and lacked any protection against eye injury.
- CR-39 lenses are as much as 50% lighter. It has two of the desired benefits: optical quality and it was lighter than glass. But, it too lacked the required safety feature and shattered on impact.
- From the regulations and legal aspects of lens manufacturing / dispensing came the next generation of “space age polymers”: Trivex™. In the late 1990s, a copolymer was developed by Simula, Inc. of Phoenix, Arizona, for use in helicopter and airplane canopies as “transparent armor.” It was also used in individual body armor. This copolymer was lightweight, durable, and strong enough to resist bullet. Pittsburgh Plate and Glass (PPG) immediately saw the benefit of transforming the copolymer into a material for ophthalmic applications. They acquired the license to develop the material, and enlisted the help of Hoya of North America and Younger Optics. Known as Phoenix by Hoya and as Trilogy by Younger, Trivex is said to have a triad of features offering benefits that no other lens material has: strength, light weight, and excellent optics.
- Trivex has a triad of benefits. The Trivex lens designers have incorporated the most desirable attributes into one lens material. It combines good optical quality with the lightest weight material which will meet FDA impact resistance as thin as 1.0mm. Trivex material (along with polycarbonate) are the only two materials that meet the ‘high impact’ requirements of the ANSI Z-87.1 – 2003 for occupational lenses.
- Trivex has the lowest density of any lens material. The specific gravity of Trivex, also known as relative density, is 1.11 grams per cubic centimeter (1.11gm/c3). That means that the weight of a cubic centimeter of Trivex material is 1.11 grams compared to a cubic centimeter of water, which is 1.0 gram. That makes Trivex 11% heavier than water. As a reference, polycarbonate is 1.21gm/c3, which makes it 21% heavier than water. Trivex is 19% lighter than CR-39 and up to 11% lighter than poly. The thinness of a Trivex lens also contributes to its light weight. Trivex lenses can have a 1.0 center thickness for dress eyewear and still pass the drop ball test (3 mm is still recommended for safety eyewear). Note: Specific gravity is a term used to indicate the weight of a lens material. The weight and thickness of an actual lens may differ from the assumed specifications that are based on specific gravity. The combination of the index of refraction, frame size and prescription will determine the final dimensions of a particular lens.
- Lens materials with low ABBE Values tend to display color fringes in peripheral areas of the lens. As the power of the lens increases, chromatic aberration and peripheral distortion increase, causing poor visual acuity. Trivex has one of the lowest reflectance values. It also has the lowest birefringence, which is the refraction of light in two different directions as it passes through a lens. Trivex’s ABBE Value, which is a measurement of the separation of light into its component colors as it passes through a lens, is 43-46, depending on the manufacturer. The ABBE Value is inversely proportionate to the chromatic aberration induced by the separation of light. The higher the ABBE Value, the lower the chromatic aberration. CR-39 has an ABBE value of 58 and polycarbonate’s ABBE Value is 29. Trivex has the second highest ABBE value of plastic materials.
- Ultraviolet Protection While plastic lenses only block 50% of the ultraviolet light, Trivex offers 100% UV protection. By age 18, children will have been exposed to 80% of the ultraviolet rays that they will be exposed to in their lifetimes. Because Trivex provides 100% Ultraviolet protection and has excellent tintability, it is a perfect material for sunglasses for children and adults
- How plastics perform is directly related to their molecular structure. Trivex’s superior tensile strength comes from the molecular technology with which it is produced. The lens manufacturers that produce Trivex lenses have developed methods of combining PPG’s thermoplastic and thermosetting monomers when casting their lens designs. Trivex is the first material optical material to combine the best of both structures.
- It is this combination of thermoplastics and thermosetting plastics that give Trivex its strength. The molecules of thermoplastics are in lines or long chains with very few linkages between them. When heat is applied, the molecules move apart, which increases the distance between the chains and further decreases the links between them. This allows the material to become soft when heated so that it can be molded into shapes. Thermoplastics can be reheated and reshaped repeatedly. The molecules of thermosetting plastics are heavily cross-linked. They form a rigid molecular structure and, whereas in thermoplastics the molecules sit end to end, the molecules in thermosetting plastics sit end-to-end and side-by-side. Thermosetting plastics remain rigid and non-flexible, even at high temperatures. Although they soften when heated the first time, which allows them to be shaped, they become permanently stiff and solid when cooled, and cannot be reshaped.
- This superior tensile strength makes Trivex six times stronger than CR-39, sixty times more impact resistant, and able to withstand 130-180 lbs. of pulling force. It is twice as scratch resistant as polycarbonate, and is chemical / heat resistant. It far exceeds FDA impact resistance standards. Trivex is the recognized material of choice for drill mountings due to it high tensile strength. Unlike polycarbonate, drill holes will not stretch with time. The drill holes maintain their shape and the surrounding material won’t crack or stress.
- Polycarbonate with a 1.0 center thickness passes the standard FDA test for impact resistance of a 5/8” steel ball dropped from a distance of 50 inches. The standard test for impact resistance doesn’t demonstrate the strength of Trivex. A test known as the High Mass Test shows the true strength of Trivex. A 1.1 pound (500 gram) missile shaped metal rod 1 inch in diameter is dropped from a height of 100 or more inches. The rod is dropped on a lens placed in a holder similar to an ophthalmic frame. At these very high energy levels the missile will drive the Polycarbonate lens through its holder by turning it inside out, but will not affect the Trivex lens. The lens passes the test if it doesn’t break or splinter, or fall through and bounce out of the holder.
- Because of their superior impact resistance, Trivex lenses are recommended for children’s eyewear. They are safer than traditional lens materials because they don’t break if impacted by fast-moving objects, such as stones, BBs, a ball and other sports projectiles.
- Over 100,000 Americans suffer sports-related eye injuries every year. Of these, approximately 48,000 require emergency room care. Trivex lenses can minimize these injuries when combined with sports frames (many of which are made of polycarbonate material). Trivex lenses are recommended for such sports as: Baseball Softball Racquetball Tennis Badminton Soccer Ice hockey Paintball Street hockey Basketball Lacrosse Archery Fencing Boxing Karate Swimming and water sports
- Trivex is available in - Finished Single Vision, clear and Transitions Gray and Brown Finished Single Vision Aspheric, clear and Transitions Gray and Brown Semi-finished Single Vision, clear and Transitions Gray and Brown Flat Top 28 Bifocal, clear and Transitions Gray X-cel’s 7x28 Trifocal, clear and Transitions Gray Augen Optics’ Trinity, clear Excelite’s X-Pro Minuo TVX, clear Excelite’s X-Pro Omnis TVX, clear HOYA’s Hoyalux GP Wide, clear, and Transitions Gray HOYA’s Summit ECP, clear and Transitions Gray HOYA’s CD, clear and Transitions Gray Shamir’s Genesis, clear Signet Armorlite’s KODAK Concise™, clear Signet Armourlite’s KODAK Precise, clear Signet Armorlite’s Unique, clear and Transitions Gray and Brown Vision Warehouse’s Stealth 15, clear X-CEL’s Aris Transition Freedom, Transitions Gray Younger’s Image, clear and Transitions Gray
- Front coating is provided, backside coating can be applied for maximum protection. Standard and premium antireflective coatings work well with Trivex. Roll-and-polish edge treatment results in a high luster, highly reflective appearance
- DrillingTrivex’s hybrid polymeric structure makes drilling easy. The material won’t melt, even under moderate drilling pressure. The drill bits must be of good quality and sharp. Use surface saver tape to protect the lens and any coating on it. A lower drill setting will keep the material cooler and prevent distortion of the material. Apply light pressure. As with all materials, don’t bear down on the drill, let the bit do the work
- EdgingEdger manufacturers are providing equipment engineered specifically for Trivex material. These machines automatically providing the correct rotation speed, water usage and lens settings to prevent overheating and stressing the lens. New edger technology provides variable wheel settings to prevent stressing the material. Ideally, Trivex is edged partly dry and partly wet. This makes for a smooth bevel and finishing treatments on the edges. On equipment that does not have specific Trivex settings - Use a vacuum system to remove swarf and eliminate airborne dust. Use an aggressive roughing wheel Use the polycarbonate setting, dry 1st cut, wet bevel cycle Acrylic or “other material” settings can also be used Use slow wheel speed if the choice is available Use the polycarbonate setting on edgers with high-speed lathe cutters When in doubt, consult with your edger manufacturer’s tech support
- In 2002, PPG commissioned two research studies. The first revealed that: ECPs reported that their patients appreciated the excellent optical clarity of Trivex lenses; Patients prefer light weight over thinness; Trivex is an excellent choice for drill-mount and rimless frames; Trivex is an excellent alternative to other plastic and polycarbonate lenses. Eyecare professionals were asked to rate their satisfaction with various aspects of Trivex. They were very satisfied with the lens overall, and most satisfied with the impact resistance, light weight and optical quality.
- The second research project was a mail survey of optical labs. The results showed: They recognized the value of Trivex in drill-mount applications because of it’s high tensile strength;They considered Trivex a viable alternative to CR-39, high-index, mid-index and polycarbonate
- Ask lifestyle questions to learn patients’ work habits, work environments, home environments, hobbies and avocations so you can recommend the lens designs that are available in Trivex. Ask general questions such as: What tasks does your job entail? Do you use a computer? Does your job or hobby have the potential to cause injury to your eyes? Then get specific.
- Whether your patients are office workers or construction workers, everyone wants (and needs) clear, crisp vision to work comfortably and safely. Explain that Trivex has high light transmission, providing excellent clarity and that it is free of peripheral and color distortion. Ask questions such as: Do you work in fluorescent lighting? Do you work in low lighting? Does your safety depend on clear, crisp vision? Do you work with color?
- For skiers, hikers, sports players and everyone who uses equipment or tools, Trivex is the material of choice for strength and safety. Explain that Trivex is excellent for hobbies, sports, athletics, and just playing outside, thanks to its impact resistance and ultraviolet protection. Ask questions such as: Do your hobbies involve sports or athletic equipment? Do you spend a lot of time outdoors? Do you work with chemicals? Do you work with tools, such as hammers, saws, grinders, etc.
- Eyeglass wearers want their eyewear to be comfortable and attractive. Explain that Trivex is lightweight and can be made very thin. This makes them comfortable, and perfect for the latest frame fashions. Ask questions such as: Wouldn’t lightweight eyewear be more comfortable? Wouldn’t your high prescription look better in a thinner lens? Wouldn’t you like to wear the latest styles in frames?
- Seniors like to look good and be comfortable as well. But, they have additional requirements and preferences than younger patients. Visual concerns, such as cataracts and macular issues must be addressed. Frame fashion and lens designs are some of the considerations we must be aware of with seniors. Explain how Trivex’s lightness will be more comfortable and how the Ultraviolet filtering can protect the health of their eyes. Mention they can have some of the most advanced lens designs in this comfortable, protective lens. Ask questions such as: Wouldn’t you like to prevent damage to your eyes from the sun? Wouldn’t you enjoy eyewear that is comfortable on your nose? Wouldn’t you like to wear the latest in lens technology?
- Trivex offers benefits to your patients that most other lenses cannot. Those benefits are Clarity, Strength and Light weight. Clarity provides optical perfection with more contrast, sharpness of vision. Strength provides protection from eye injury with high impact resistance. Light weight provides comfort.
- Offering Trivex to patients benefits the practice through patient satisfaction, retention and referral. Trivex makes an excellent choice for the latest in frame fashions. Every patient who desires and requires crisp, clear vision and for those who need protection against Ultraviolet rays, and eye injury will benefit from Trivex. Providing Trivex positions your practice as a leader in technology. The latest lens designs are available in Trivex. Trivex is an excellent choice for everyday eyewear. But is also is excellent for specialty eyewear as well. Trivex, with its triad of features: impact resistance, light weight and optical clarity, is rapidly becoming the “space age polymer” of choice.