|Patients are impressed with benefits found in today’s AR treatments, such as Opticote’s tzAvoRite as seen in the simulated lens image (left without, right with).|
AR treatments continue to incorporate new features, further proving itself as a valued lens option.
Anti-reflective (AR) treatment processing is a mature technology with more than a 40-year history of being placed on lenses. It began with Crown glass and eventually transitioned to plastic materials as they became popular. Even so, AR technology is still making advances that benefit patients in a number of ways. Here’s a look at the latest trends in this category.
Earlier AR treatments had a bad reputation for occasionally crazing or peeling. Current cutting-edge premium AR treatments are designed to remain attached to the lens for the life of the patient’s prescription. AR treatment processors accomplished this through a couple of methods,
|The most prominent feature of HOYA’s Super HiVision EX3 AR technology is its scratch-resistant quality.|
one of them being an improvement in hardcoating technology. Since plastic lenses are soft, the thin AR treatment layers will flex when the lens is flexed or impacted, creating the potential for the AR layers to crack. To avoid this, a hard surface coating on the lens acts as a strong foundation that helps the coating layers absorb impact and avoid crazing and cracking.
Another strategy is known as substrate matching. In this process, the AR treatment producer formulates the composition of each individual hardcoating recipe based on the needs of the specific lens material being treated. This helps produce superior bonds with the AR layers above and the lens materials below. Several manufacturers use this method in their process, such as Carl Zeiss Vision Inc. with its Teflon® Clear Coat Lenses and Opticote, Inc. with its tzAvoRite AR treatment.
|IN-HOUSE AR TECHNOLOGY Optical Dynamics has provided a convenient option for eyecare professionals (ECPs) to provide anti-reflective (AR) lenses in-house. With the nanoCLEAR AR™ unit, ECPs can easily deliver premium AR lenses to their patients in a short period of time (about 90 minutes)—increasing the percentage of AR lenses sold. The system, designed to work in conjunction with the company’s Q-2100R™ Digital Lens System, incorporates the latest in nano particle technology. Through the curing process a chemical bond is formed between each layer of the AR stack, the hardcoat, and the lens substrate. The lens comes out of the mold with very durable AR properties already built-in that has long lasting performance and is easy to clean.|
Once patients make the decision to purchase AR lenses, the next thing they expect is that the lenses provide their AR benefit for a long time. When they purchase premium lenses like Essilor of America, Inc.’s Crizal® Sapphire™ with Scotchguard™ Protector or Crizal Avancé™ with Scotchgard Protector, that’s exactly what they get—top-of-the-line durability.
One way this strength is created is by adding an SR Booster™ Layer on top of the hardcoat and before the AR stack is applied to the lens. This intermediate layer acts as an additional buffer in preventing scratching and builds a descending stack of hardness, beginning from the particularly hard minerals in the AR blend, all the way down to the soft substrate of the lens material.
Hydrophobic coatings have been applied to high-end AR treatments for several years, serving as the outer barrier of the AR lens. This outer layer’s job is to repel moisture from the front and back lens surfaces. When properly done, this layer rolls water droplets right off the surface by creating a high surface tension. A feature like this may come in quite handy the next time a patient walks in the rain without an umbrella.
HOYA VISION CARE, North America’s third-generation AR technology is
|Signet Armorlite’s KODAK Clean’N’CleAR Lenses ward off fingerprints.|
Super HiVision™ EX3. According to the company, its most prominent feature is its superior scratch-resistant quality. Results from a variety of rigorous testing outcomes rate EX3’s scratch resistance superior to that of mineral glass. As with the other HiVision technologies, every element of the thin film coating in the EX3 formula is index-matched with each lens material it is polymerized with, providing for a consistent 99.5% light transmission across the entire visible light spectrum and the absence of birefringence color rings on lens surfaces.
Some treatments also ward off fingerprints, wax, and grease—arch enemies of eyeglass wearers who want clear vision out of their lenses with as little lens cleaning as possible. In order to do this, coating developers added an oleophobic property to their treatments. Products providing this feature include KODAK CleAR™ and Clean’N’CleAR Lenses (by Signet Armorlite, Inc.).
Another is Carl Zeiss Vision’s PureCoat™ by ZEISS, which was tested at COLTS Laboratories to measure oil disruption. After oil was measured and poured onto multiple lenses, PureCoat by ZEISS demonstrated a super low 2.7% haze after 20 rubbing cycles, and 0.7% haze after 60 rubbing cycles, making it one of the most oil-resistant lens coatings on the market.
Dust, lint, and static have plagued lens wearers for decades so when they hear that modern premium AR lenses are easy to clean and keep clean, they welcome the news. When patients rub their lenses during cleaning, a static electricity charge is built up on the surface of the lens. This static charge attracts minute particles that build up on the surface. The more the person rubs the lens, the stronger the charge gets and the more the lens attracts the particles. AR lens manufacturers have developed ways to overcome this by treating their coatings in such a way that they ward off static electricity, thereby making the lens surfaces more neutral, which helps keep particles from being attracted to the lens.
Down the road, look for companies to continue tweaking their products to improve the features they currently offer, such as higher levels of surface reflectance, and hydrophobic and oleophobic properties, more scratch resistance, and greater durability.
Since a number of manufacturers and coaters have more than one AR treatment available, look for more good, better, best AR lens menus from suppliers (see “Tiering Creates AR Choices,” page TK). This kind of availability will provide patients with choices, which will also help promote a higher usage of AR lenses.
Eyecare professionals (ECPs) can expect to see more AR treatments applied to lenses with package pricing. Similar to purchasing a pair of 1.70 or 1.74 high-index lenses that automatically comes with an AR treatment, look for more lens materials and designs to come this way.
This trend has also begun to transition through the stock lens world, where ECPs can now order finished lenses in polycarbonate, 1.56, 1.60, 1.67, and CR-39® and Trivex® materials as well as CR-39 Transitions® and polycarbonate Transitions—all with AR treatments. This trend can save ECPs thousands annually on their lab costs as well as get more patients into AR lenses.
The advances in AR lenses continue to impress ECPs and patients alike. As manufacturers continue to provide new innovations, this category of lenses will become as common place as anti-scratch lenses are today.
Francis Gimbel, Jr. is an optician, private consultant, and manager of the PENN Optical Department at the University of Pennsylvania.
WHERE TO FIND IT
Carl Zeiss Vision Inc.
800-358-8258 • zeiss.com/lenses
Essilor of America, Inc.
800-542-5668 • essilorusa.com
HOYA VISION CARE, North America
877-528-1939 • hoyavision.com
800-587-2743 • opticaldynamics.com
800-248-6784 • opticote.com
Signet Armorlite, Inc.
800-950-5367 • signetarmorlite.com