continuing education

The Right Stuff: Single Vision Lenses Today

Learn what's new and review what's tried and true about single vision to help your practice and professionalism thrive

Single vision lens features and benefits have changed dramatically in the past few years. For example, premium single vision lenses like those with aspheric/atoric qualities, wrap and rimless capabilities, and photochromic and AR technologies are driving the single vision market today.

Knowing where the single vision lens marketplace is now and will be in the future will help you and your practice plan product launches, ad and marketing campaigns, and internal strategies like education and training, incentives, and patient interactions for the best success.

SINGLE VISION: MORE IMPORTANT THAN EVER

According to The Vision Council, in the latter part of 2007 there was a surge of younger eyeglass wearers. However, the trend of increasing Rx eyeglass usage among 18- to 34-year-olds did not hold up throughout 2008. Usage rates returned to levels observed in 2004 to 2006, and the anticipated increase in younger eyeglass wearers never really materialized. Instead, contact lens usage is growing among younger demographics and now younger Americans are more likely than older Americans to have a LASIK procedure.

Additionally, the eyeglass repurchase cycle is higher for younger Americans than older Americans and there has been a decline recently in single vision lens sales in the U.S.

That said, why is single vision more important than ever? Because even with a relative decline in single vision sales, new products and technologies, and, in particular, premium single vision products, present the opportunity to increase sales and profits. Some new areas to target single vision usage include:

1. Age 34+ non-presbyopes

2. Age 18 to 34 first pair upgrade

3. Youth (infant to 18 years) eyewear

4. Post-LASIK plano sunwear

5. Rx and ready-made readers

Also focus on yearly exams and eye health check-ups for all age groups to promote healthy eyes, enhance lifestyles, and provide optimal visual clarity.

FEATURES & BENEFITS

Each lens material (high index, polycarbonate, plastic) provides specific features and benefits. In other words, the lens substrate imparts static and reliable features and benefits (high index = thin and light; poly = strength, etc.). Lens designs, however, can and do change, and what's offered with each, including scratch resistance and UV protective qualities, can vary between manufacturers and even from lens to lens within the same manufacturer's portfolio.

Glass: 1.52 index

Features: Inherently scratch resistant, superior optical clarity, best AR adhesion, must be tempered for impact resistance, heavy weight

Benefits: Highly resistant to scratching, best edge-to-edge visual clarity, longer-performing and durable AR

Note: Glass lenses are also available in high-index 1.60, 1.70, and 1.80 indices. and can be dispensed in the U.S. with written permission from the patient.

Plastic/Hard Resin: 1.50 index

Features: Lightweight, tintable, scratch resistant only if hard-coated, UV protective if coated, thicker and heavier in high powered Rx's than other plastic materials

Benefits: More comfortable to wear than glass, easily tintable to almost every shade and density. Using UV and hard-coated lenses are recommended.

Polycarbonate: 1.59 index

Features: Highly impact resistant, lightweight, and thinner than glass or hard resin, inherently UV protective, must be hard-coated for scratch resistance

Benefits: More comfortable to wear than glass or hard resin, hard coating makes lenses scratch resistant but difficult to tint. Naturally UV protective, impact resistance makes poly lenses safer for children, active adults, and industrial safety wear.

Trivex: 1.53 index

Features: High impact resistance, lightweight, inherent UV protection, tintable, optical clarity similar to glass, high tensile strength, must be hard-coated for scratch resistance

Benefits: Lightweight for wearing comfort, edge-to-edge visual clarity, ideal for rimless mountings, ultra-safe with reliable durability.

High index: 1.60, 1.66, 1.67, 1.71, and 1.74 indices

Features: Aspheric/atoric designs are standard in most high-index products for flatter curves, lower Abbe value; must be hard-coated, and should be AR coated.

Benefits: Thinner and lighter than other lens materials, backside and internal reflections are correctable with AR; dramatic reduction of lens edge thickness (minus lenses) and center thickness (plus lenses) for cosmetic enhancement and wearing comfort.

CONNECTING SINGLE VISION AND AR

What you need to know: Applying anti-reflective coatings to lenses is a complex computer-controlled process, and each manufacturer's proprietary requirements call for precise systems management. Multi-layer AR stacks include a top coat, index layers, conditioning layers, adhesion layers, pre-treatment layers, and scratch resistant layers.

Quality of the top coat (hydrophobic, oleophobic) and scratch resistant layers is also important. Many of today's AR stacks offer super hydrophobic topcoats that are "slippery" and require the use of special pads to edge the lenses without slipping off axis.

Manufacturers use multiple layers to create AR coatings because multiple layers are required to eliminate reflections of most wavelengths. However, small amounts of reflection, residual reflectance, remain and causes a subtle color to AR. These are typically blue, gold, or green, although there is also at least one AR on the market today that is color-free. AR coatings for sunlenses have also been developed that have little or no residual reflection. Manufacturers often use residual reflection to identify their products and to coordinate with sunlenses and mirror colors for fashion and function.

What patients need to know: Today's AR lenses provide features everyone looks for: scratch resistance, UV protection, and protection from distracting glare and reflections. Additionally, the lenses resist the "three Ds:" dirt, dust, and debris, as well as water drops, oils, smudges, and fingerprints.

While scratch resistance and AR are more durable today than they've ever been, lenses must be properly cared for in order to perform their best. This includes using only an AR-approved cleaning cloth and cleaner and keeping eyewear in a protective case when not in use. Cleaning lenses using any other method—wiping when dry, using a tissue or paper towel, using a shirt, using household cleaners—is not recommended and may cause lenses to lose their durability over time.

TOP TIMES TO RECOMMEND SINGLE VISION AR

1. Upgrade: For those patients who have never had AR or those who have tried AR unsuccessfully in the past. New AR technology offers peace of mind for eyecare professionals and their patients with solid performance and durability.

2. Visual acuity for adults: In everyday situations, young adults spend a lot of time in varied environments: driving, office/work, home, and recreation. AR can help them transition from varied lighting-caused reflections in each environment to see their best and to let their eyes be more at ease.

3. Visual acuity for kids: Today's tough and durable AR can stand up to kids' wear and tear, plus deliver what kids and parents want most: the best possible visual acuity for the best performance possible in and outside the classroom.

4. Comfort: AR can help alleviate end of the day visual and physical discomfort from being on a computer and performing other office tasks by eliminating annoying reflections.

5. Performance: When visual clarity and acuity are crucial, such as when driving, at the workplace, or during sports, AR can help kick up the performance notch so patients miss nothing due to reflections.

TOP SINGLE VISION TERMINOLOGY

Connecting terms to phrases used most often when the single vision lens market is discussed can help you achieve a better understanding of what single vision lenses do. It can also help you evaluate products efficiently in order to make the best recommendations honed to each patient's needs.

Aspheric: Asphericity is an important component in achieving a thin, flat lens profile for better cosmetics. Aspheric properties help reduce distortion, magnification, and minification, resulting in wearers experiencing more natural vision.

Atoric: Atoric lenses use a spherical front surface with backside cylinder curves that are individually asphericized, so optics are maximized for both sphere and cylinder powers. Atoric lenses offer a wider field of view.

UV Protection: Protection from harmful ultraviolet rays is currently the leading buzz phrase when discussing healthy sight with patients and when detailing lens features and benefits for them. While glass and Trivex materials are inherently UV protective, other lens materials must be coated in order to offer UV protection, and levels of UV protection can vary. ANSI Z80.3 Sunglass and Fashion Eyewear Standard are voluntary for manufacturers, with cosmetic, general, and special purpose UV requirements. Special purpose UV blocks at least 99 percent UVB and 60 percent UVA.

Scratch Resistance: In addition to supplying resistance to scratches, hard coatings provide the base for AR. The efficiency of an AR depends on the surface below it, which must be faultless to achieve AR performance/durability.

Photochromic: Today's photochromic lenses—activated by UV light—get darker outside and clear inside. These lenses protect vision by blocking UV radiation, and increase visual comfort by reducing discomforting and disabling glare. A recent study conducted by a leading photochromic manufacturer showed that that an "overwhelming number of the patients studied preferred AR-coated lenses" and found that this "provides compelling support for the clinical decision to recommend [photochromic] lenses with AR coating to all appropriate patients."

Polarized: Polarized lenses help eliminate distracting and blinding glare for the best visual acuity and performance in outdoor environments. Polarized photochromic lenses change density according to the environment, and new polarized photochromic technology uses visible light as well as UV light to activate. AR on the backside of a polarized lens stops back-reflections caused when the sun is positioned behind and/or to one side of the wearer. Additionally, AR on the lens' front side helps cut out reflectivity coming from in front of the wearer.

GETTING THE EDGE ON FRAMES

Single vision lenses offer wearers more frame options, since PAL lens limitations like segment height don't apply. Patients with high-powered Rx's—typically anything over +/- 5.00D—should be fit in small frames that place the center of the pupil as close as possible to the center of the lens. This, combined with the selection of a high index lens, helps keep lens thickness to a minimum.

Most labs recommend a satin polished edge with no roll to help avoid the "ice cube effect" that a high-luster polished, rolled edge can create, which can cause the patient to reject the eyewear due to unsatisfying cosmetics and/or distracting reflections. An alternative or addition to a polished edge is a light cosmetic tint applied to match the wearer's skin tone.

For many wearers, single vision lenses can fit in practically any frame. Today's fashion spectrum runs from rimless three-piece mountings (barely-there frames) to geek chic (big, thick, clunky frames) and anything in between.

When it comes to frame shape, remember that a square or rectangle shape can create sharper, thicker edges. A round or oval shape offers the smoothest, thinnest edge option.

That said, the bigger the frame the thicker the edge, so if reducing lens weight and edge thickness is the goal, the smaller the frame size, the better.

For many patients with a single vision Rx, varying circumstances may call for different frames, either from a fashion and/or function standpoint. Some examples include:

1. Work/dress: The pair of eyewear worn to the office—say, a tortoise shell or black plastic frame—may not be the look the patient would like on their off hours; when they're socializing or relaxing, they may prefer a three-piece mounted rimless style.

2. Special occasion: Public speaking or a performance, a wedding ceremony or prom, or any other special event in a patient's life may call for a particular pair of eyewear that marks the occasion and helps encourage the wearer to feel and look special.

3. Sports/safety: Sunwear or indoor wear with lenses geared for a particular sport, plus safety frame and lens materials, are important for those who are active in any sport for eye protection and the best performance. These frame and lens styles —for example, large wrap-around designs—are typically not worn in everyday situations.

4. Computer/hobby: A single vision Rx modified for computer use can be an anti-eye-fatigue boon for those who use a computer for several hours a day. Paired with durable yet stylish frames, these lenses can be more of a go-to than a regular pair for long hours at a desk.

A single vision Rx modified for hobbies like jewelry making, sculpting, painting, tinkering on vehicles, collecting, or card/board game playing, to name a few, can make leisure activities even more relaxing by offering visual acuity and relief from eye fatigue.

5. Back-up: Back-up eyewear in the patient's current Rx and frame choice is important for them to have on-hand, not only for the best visual performance in case of primary pair breakage, but as a wearable alternative to an everyday pair of eyewear.