Quest for the Holy Grail

By Shirley Ha, BSc., O.D.

makingcontactIt’s no secret that traditional hydrogel daily disposables, and, more recently, silicone hydrogel daily disposables, have added a new dimension to our practices. The ease of fitting, convenience, easier care instructions, and the oxygen benefits of silicone hydrogels are fueling the growth of this market in Europe, Japan and North America. Yet, they are still not the be-all solution for every patient.

Despite the greater oxygen transmissibility these lenses provide, the higher modulus, the poorer wettability and affinity to lipid deposits are causing patient symptoms and comfort problems. Data from 372 completed surveys in 27 countries around the world cite discomfort (41.9 – 52.9 per cent) as the primary reason patients drop out of contact lenses, followed by poor vision (3.8 – to 17.5 per cent) and cost (11.6 – 17.5 per cent).[1] Over time, this can negatively impact practice economics.

What, then, should the holy grail of contact lenses possess so that all patients can readily uptake these lenses? There is increasing focus among researchers on the frictional forces between the lens surfaces and the ocular tissues during blinking that cause end-of-day discomfort. Clinical complications exacerbated by friction or decreased lubricity include contact lens papillary conjunctivitis (CLPC) and pathognomonic conditions, such as lid-wiper epitheliopathy (LWE) and lid-parallel conjunctival folds (LIPCOF). Notwithstanding the idealistic properties such as high oxygen permeability, ease of handling, good optics, and stable pre- and post-lens tear film, the contact lens surface should also be “corneo-mimetic”, says Dr. Desmond Fonn, Distinguished Professor Emeritus at the University of Waterloo School of Optometry. Not only should it retain moisture, it should also have a low coefficient of friction (COF) or lubricious surface.[2]

There is an ongoing race to develop the “perfect” contact lens that is “biocompatible” with the ocular environment. Different manufacturers have taken different approaches in designs to retain moisture and increase lubricity.

For example, Proclear® 1 day (62 per cent water Omafilcon A, CooperVision) has phosphorylcholine (PC) molecules within the lens matrix to attract and surround the lens with water, increasing hydration. DAILIES® AquaComfort Plus® (69 per cent water Nelfilcon A, Alcon) has three moisturizing agents: hydroxypropyl methylcellulose (HPMC) in the blister pack and polyethylene glycol (PEG) and polyvinyl alcohol (PVA) within the lens. The PEG is released from the lens early in the day and the PVA is released over time when the patient blinks throughout the day. Unfortunately, the lower Dk/t values, 28 and 26 respectively, can still put patients at risk for corneal edema and keratitis.

With advances in manufacturing technology, we are again on the cusp of an exciting new era in contact lens product enhancements, thanks to the dedicated teams of eye health researchers, bio/chemical engineers and clinicians around the world.

First is the Biotrue® ONEday lens from Bausch & Lomb. It is made with HyperGel™ (Nesofilcon A), a completely new hydrogel material that contains 78 per cent water to match the natural water content in the cornea. It has UV protection and can transmit, without silicone, sufficient oxygen (Dk/t=42) required for daily wear to prevent hypoxia. The surface of the high water content lens mimics the properties of the natural tear film to give excellent hydration, lipid resistance, lubricity and the comfort of traditional hydrogels. Because of its ability to maintain hydration and retain its shape, vision is also more stable throughout the day.

Next is DAILIES Total1® from Alcon with phosphatidylcholine, a phospholipid found in cell membranes. With an impressive Dk/t of 156, the material (Delefilcon A) is a silicone hydrogel at its core with a “water gradient” that graduates from 33 per cent water content at the core to more than 80 per cent at the lower modulus hydrophilic surface. The innovative design is easy to handle, wettable, lubricious, highly breathable and comfortable because of its soft gel front and back surfaces.

Available in early 2014 is MyDay™ from CooperVision, made with 54 per cent Stenfilcon A material with a Dk/t value of 100. It features a long network of oxygen-delivering silicone channels with hydrophilic arms called Smart Silicone™ chemistry. The company claims that since there is less silicone and more hydrophilic sites, the lens is easy to handle and naturally wettable.[3]

Despite very different approaches from these three lens manufacturers, the goal of creating a bio-mimetic lens that is wettable, lubricious or both remains the same. As with any “breakthrough” product, they require further study to see if they are really beneficial for our patients. Will the higher water content at the lens surface increase other deposits? What about lens desiccation and its effect on lens shape and optics as the ocular environment reaches homeostasis? And how much oxygen does the eye require?

In summary, patient success and retention in contact lens wear depend on your determination of what is the most appropriate lens for them. Patients want good vision and all-day comfort above all else. You want lenses that are safe and eye healthy. Understanding the newest lens designs and materials is crucial to solving comfort issues and to prescribing the best alternatives for your patients, now and in the future.



[1] RUMPAKIS, J. “New Data on Contact Lens Dropouts: An International Perspective”, Review of Optometry, vol. 147, January 2010, p. 37-42

[2] FONN, D. “Clinical Relevance of Contact Lens Lubricity”, Contact Lens Spectrum/Special Edition 2013 The World’s First and Only Water Gradient Contact Lens, vol. 28 no 13, June 2013, p. 25-27

[3] Company website. CooperVision. http://ow.ly/pbltw (Accessed September, 2013)

 

 

 

Expanding the View

By Shirley Ha, HBSc., O.D.

A team of Swiss and U.S. researchers has built a revolutionary telescopic contact lens tethered to a pair of liquid crystal eyeglasses that can switch between normal and magnified vision[i].The unprecedented contact lens system, which uses the special eyeglasses as will be explained below, could become a visual aid for those struggling with degenerative eye diseases such as age-related macular degeneration (AMD), a leading cause of irreversible central vision loss and legal blindness in older adults.

Current vision rehabilitation devices, such as external, spectacle-mounted telescopes and the more recent Implantable Miniature Telescope (IMT), magnify images in front of the eye and project them onto the healthy areas of the retina. The problem is that external, spectacle-mounted telescopes are often seen as protrusive and unattractive, while IMTs require invasive eye surgery for implantation.

“For a visual aid to be accepted, it needs to be highly convenient and unobtrusive; a contact lens is an attractive compromise,” says Eric Tremblay at the École polytechnique fédérale de Lausanne (EPFL) in Switzerland[ii].

Together with colleagues from the University of California at San Diego, Tremblay developed the 1-mm centre thickness, 8-mm diameter prototype contact lens. It has a clear central aperture of 2.2-mm for normal, unmagnified vision and an outer ring of 1.17-mm thick optics for the telescopic 2.8x magnification.

The researchers used their “origami” lens design to achieve longer effective focal lengths or zooming power[iii]. They did this by precision diamond-turning a series of tiny, reflective and non-reflective annular concentric aluminum surfaces into the lens periphery. Instead of light moving through a lens system that is several times thicker, the “folded” aspheric reflectors bounce the light internally back and forth in a pre-determined zigzag pattern within the lens periphery before projecting the final magnified image onto the retina.

To make the two independent optical paths switchable, the team applied orthogonal polarization films over the central and annular apertures and modified a pair of Samsung 3D TV glasses with liquid crystal sensors that can electrically toggle on and off the polarization in the contact lens. Instead of seeing the regular and magnified vision simultaneously, the user can selectively switch to or block either the regular, unmagnified stream in the centre or the telescopic stream on the periphery.

In its first round of experimental demonstration, the prototype telescopic contact lens design is still very basic. It is made of polymethyl methacrylate (PMMA), an outdated contact lens polymer that cannot be worn for any extended period of time because of its oxygen impermeability to the eye. Although diffractive optics are grooved into the PMMA material to fix the axial chromatic aberration that the contact lens curvature creates, the grooves make the contact lens unwearable. While the retinal field of view could be made larger than other magnifiers, the image quality and contrast captured by a life-sized optomechanical eye are degraded by higher-order diffraction from the same diffractive grooves.

The researchers are already working out the bugs. They are currently partnering with contact lens manufacturer Paragon Vision Sciences to develop an upgraded model of the telescopic contact lens using modern, rigid gas-permeable (RGP) materials that can be worn for longer periods of time. The redesign will have improved “all-refractive”, rather than diffractive, optics to enhance contrast and image quality. The team of researchers plans to begin clinical trials to test their new design on AMD patients as early as November.

Other ongoing collaborations include one with Rockwell Collins Inc., a large, U.S.-based international communication solutions company, to develop glasses with additional control and interaction, such as a wink trigger that can switch between normal and magnified vision when the gesture is registered. The researchers also believe they can eventually incorporate the liquid crystal sensors directly into the contact lens with an external remote, like the recently commercialized SENSIMED Triggerfish® system for monitoring glaucoma.

But don’t expect to see variable-focus, high-power zoom anytime soon. It will be some time before these telescopic contact lens systems become readily available to the average consumer. Funded by the U.S. Department of Defense’s Defense Advanced Research Projects Agency (DARPA), the technology could also become the future soldier’s eagle vision, helping to identify allies or enemies at far distances, or as a deadly accurate weapon-target locking device.

Eventually, this innovative breakthrough, which extends functioning vision with a contact lens that can be worn comfortably, will become available to people in the general population who suffer from permanent sight loss such as AMD.


[i] TREMBLAY, Eric J., STAMENOV, Igor, BEER, R. Dirk, ARIANPOUR, Ashkan, FORD, Joseph E. “Switchable telescopic contact lens”, Optics Express, vol. 21, No. 13, July 2013

 

[ii] Business Wire: “A Telescope For Your Eye: New Contact Lens Design May Improve Sight of Patients with Macular Degeneration”, June 27, 2013.

 

[iii] Jacobs School of Engineering, UC San Diego: “Concentric Multi-Reflection Lenses for Ultra-Thin Cameras (aka Origami Optics)”.

Confusing Side Effects: Drug Interactions and Contact Lenses

By Shirley Ha, BSc. (Hons), O.D.

The number of medications prescribed by Canadian doctors is steadily rising. According to the global market research company, IMS Health, 522.4 million prescriptions were dispensed in Canadian retail pharmacies in 2011, representing a 4.8 per cent increase from 2010 and a whopping 32.8 per cent increase over 2006. The top three drug types were for heart disease, mental illness/mood disorders and gastrointestinal/genitourinary illnesses.

When a systemic drug unintentionally reaches the cornea, lens and vitreous through the uveal and retinal circulations, it can cause unwanted secondary ocular effects. These can affect patient satisfaction with contact lens wear and the contact lens itself.

Eyecare professionals should have a working knowledge of these drug-related effects in order to distinguish them from those caused by the contact lens itself or its improper use and care. Keep in mind not everyone who takes medication will experience side effects and not all side effects are undesirable, especially with medications that have multiple indications and/or have off-brand uses.

In general, patients can experience many eye-related drug reactions, including corneal opacities and deposits, cataract, pigmentary retinopathy and optic neuropathy. Conjunctival hyperaemia, dry eye and mydriasis are examples of common conditions that may be wrongly attributed to contact lens wear.

A careful review of the patient’s case history and medications (dosage, duration and the systemic condition being treated) at each follow-up visit is the key to clarifying the nature of any problems that arise. It also allows for better patient education, collaboration with other health care professionals, and healthier contact lens care.

The following chart shows the relationship between several commonly prescribed medications and eye/vision conditions.

Myopia Control with OK lenses

By Shirley Ha, BSc. (Hons), O.D.

Myopia, or nearsightedness, affects approximately 30 per cent of Canadians and more than 1.6 billion people worldwide. The World Health Organization estimates that the number of myopes will grow to 2.5 billion globally by 2020.

Myopia often starts in early childhood and, if undiagnosed or uncorrected, it can impact a person’s educational success and job prospects. It is associated with a greater risk for sight-threatening complications such as cataract, glaucoma and retinal detachment, especially in axial myopia.

Various research projects are being undertaken around the world to reduce and/or find preventative measures for progressive myopia in children. Techniques that are investigated include atropine/pirenzepine, bifocals and progressive addition lenses (PALs), under-correction, soft multi-focal contact lenses, modified spectacle lenses and the controversial orthokeratology (OK).

For decades, eyecare practitioners have used OK to correct moderate myopia and low with-the-rule astigmatism in children and adults. These customized reverse-geometry rigid gas permeable (RGP) contact lenses, also known as non-surgical corneal reshaping (CR), are worn during sleep and removed on wakening and can provide patients with clear vision and all-day freedom from glasses and contact lenses, usually within one to two weeks. The added possibility of myopia control makes OK a very attractive mode of correction, especially in children.

In recent years, multiple studies have provided strong evidence that OK can effectively reduce myopia progression in children and slow axial elongation.[1],[2] Impressively, the third-year report of the five-year longitudinal Stabilization of Myopia through Accelerated Reshaping Technologies (SMART) Study[3] and the Controlling Astigmatism and Nearsightedness in Developing Youth (CANDY) Study[4] both showed greater than 80 per cent decrease in axial length in children with OK compared with the soft contact lens control groups.

Researchers theorize that the focus or defocus of the peripheral retina dictates the development of a person’s refraction. The “traditional” contact lens or flat-form spectacle lens encourages ametropia because it does not address the increasing defocus/blur from the centre to the equatorial/peripheral retina created by the difference between the curvatures of the optical lens and the retina. This peripheral defocus can impede the normal correction of ametropia in children called emmetropization and can send a signal within the retina to keep elongating in a myope.[5]

The key to myopia control is to develop treatment modalities that can manipulate the peripheral images back onto, or in front of, the peripheral retina to stop the retinal signal for ocular growth.

Scientists at the Vision Cooperative Research Centre (Vision CRC) in Australia followed their own model and pioneered a new generation of optical products to reduce peripheral hyperopic defocus: the MyoVision™ spectacle lens and silicone hydrogel contact lenses. Their respective clinical trials and studies of their modified products confirmed their hypotheses that decreasing peripheral hyperopia also reduces the rate of myopia progression.[6],[7] Both Zeiss and Ciba Vision were given exclusive licensing rights from Vision CRC to incorporate the myopic control technology into their products.

The same myopia control theory can be said to occur in OK as well – the flatter central base curve compressing the central cornea during sleep also displaces the anterior corneal layers outward into the mid-peripheral annular steeper radius to create an artificially more myopic peripheral retina, correcting the hyperopic peripheral defocus and eliminating the stimulus for axial growth.

Unlike refractive surgery, OK is not permanent and discontinuing lens wear will cause the cornea to revert to its original shape. If OK can, in fact, control and decrease the progression of axial length growth and stop the eyes from becoming more nearsighted, then children fitted in early childhood will have their eyes return to the way they were before treatment – when their myopia levels were low – not to where their eyeball lengths would otherwise have been years later when they stop lens wear. This is indeed promising.

The risks associated with wearing OK lenses are similar to those associated with other contact lenses. Doctor supervision and strict adherence to proper wearing schedules and lens maintenance will minimize side effects and make OK safe and effective.

The Canadian Ophthalmological Society does not currently endorse overnight OK and cites microbial keratitis as a major risk factor; OK is recommended by the American Academy of Optometry as an alternative to refractive surgery; the Canadian Association of Optometrists does not have a policy or position paper on the matter.

There are two current FDA-approved technologies for overnight OK lenses: Paragon Vision Sciences’ Paragon CRT® and Bausch and Lomb’s portfolio of Vision Shaping Treatment (VST) designs. Certification from the manufacturers is required for all practitioners. At present, there are no written guidelines to help practitioners implement the results of OK research into actual clinical practice, except those provided by the manufacturers.

While OK might be highly controversial to some, the rising rates of progressive myopia in children present an incredible growth opportunity for those who are prepared to take on the OK specialty and “reshape” the future of their contact lens practice.



[1] WALLINE, Jeffrey J. “Myopia Control with Corneal Reshaping Contact Lenses”, Investigative Ophthalmology & Visual Science, vol. 53 no 11, October 2012, p. 7086.

[2] HIRAOKA, Takahiro, KAKITA, Tetsuhiko, OKAMOTO, Fuimiki, TAKAHASHI, Hideto, OSHIKA, Tetsuro. “Long-Term Effect of Overnight Orthokeratology on Axial Length Elongation in Childhood Myopia: A 5-Year Follow-Up Study”, Investigative Ophthalmology & Visual Science, vol. 53 no 7, June 2012, p. 3913-3919.

[3] DAVIS, R, EIDEN, SB. “Stabilisation of myopia by accelerated reshaping technique (SMART) study. Third year interim report”, Specialty Contact Lens Symposium Meeting, 2011.Las Vegas.

[4] BARTELS, David, WILCOX, Peter E. “CANDY: Controlling Astigmatism and Nearsightedness in Developing Youth” http://CANDY-OrthoK-study.pdf accessedMarch 27, 2013.

[5] SMITH, Earl L. “Optical treatment strategies to slow myopia progression: Effects of the visual extent of the optical treatment zone”, Experimental Eye Research, January 2013.

[6] SANKARIDURG, P, DONOVAN, L, VARNAS, S, HO, A, et al. “Spectacle lenses designed to reduce progression of myopia: 12-month results”, Optometry Vision Sciences, vol. 87, no 10, October 2010, p. 631-41.

[7] SANKARIDURG, P, HOLDEN B, SMITH E 3RD, NADUVILATH, T, CHEN, X, de la JARA, PL, et al. “Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results”, Investigative Ophthalmology & Visual Science, vol. 52 no 13, December 2011, p. 9362-7.

Incompatible Solutions?

By Shirley Ha, BSc. (Hons), O.D.

Wearing contact lenses increases the risk of complications such as corneal infiltrative events (CIEs). Over the last few years, a growing number of reports show an increase in a newly classified, non-infectious CIE called contact lens-associated infiltrative keratitis (CLAIK). It is especially prevalent in patients using certain silicone hydrogel (SiHy) lens and multi-purpose solution (MPS) combinations[i],[ii],[iii].

Anecdotal cases from private practitioners are also on the rise, with two Minnesotaoptometrists recently claiming to have linked more than 35 cases of CLAIK to one leading contact lens solution.[iv]

Yet, according to Dr. Robin Chalmers and her team at the Indiana University School of Optometry, the incidence of CIEs was over three per cent per year in their retrospective chart reviews of 3,549 multiple-brand SCL wearers.[v],[vi] This is in agreement with Carnt et al., who also found a similar overall CIE incidence rate of 3.1 per cent with their 558 participants.[vii]

Additionally, 166 subjects, using more than 45 lens solution combinations in another retrospective, multicentre, case-control study showed no significant increase in CIE risk with any single contact lens brand, lens care product or combinations.[viii]

The relationship between “sterile” infiltrates and the use of SiHy-MPS combinations was first observed in 2007 when researchers identified fluorescein staining concomitant with infiltrates as a sign of cell cytotoxicity.[ix] Others suggested the corneal staining was not associated with infiltrates but rather related to the MPS preservatives binding to the fluorescein dye (PATH) and was transient and non-cytotoxic.[x]

Furthermore, new research is emerging to indicate that sodium fluorescein can enter and stain living or early apoptotic cells and solution-induced corneal staining (SICS) may not be an appropriate evaluation of solution toxicity anymore.[xi]

Some proposed that infiltrates come from the direct, physical insult associated with having a SiHy lens in the eye. The higher modulus SiHy material on the cornea, lids and adnexa triggers an antigenic or foreign body response to release inflammatory mediators that cause CLAIK, giant papillary conjunctivitis (GPC), corneal neovascularization, and mucin ball production.[xii] Also, SiHy fits are usually tighter than conventional hydrogels to prevent “fluting” or excessive edge lift. The poorer tear exchange, along with the absence of the blinking process on the back surface of the lens, allows debris, deposits and microbial biofilm, including released endotoxins, to build up and become additional stimuli for an immunological response.[xiii] The hypothetical pathophysiology may explain why some studies paradoxically show a two-fold greater risk for CIEs with silicone hydrogels than with conventional hydrogels.5

Other identifiable risk factors for CLAIK include, but are not limited to, exceeding the recommended wearing schedule and poor compliance, such as lack of hand washing, failing to rub and rinse contact lenses, case contamination, topping up solution, inadequate case hygiene, and not replacing cases at least once a month.[xiv]

Typically, patients with CLAIK will present with bilateral, small, diffuse, epithelial or sub-epithelial, grey, granular infiltrates in the central or entire cornea. They are different from the unilateral, single, round, sub-epithelial or anterior stromal, grey-white, mid-peripheral to peripheral infiltrates seen in infiltrative keratitis (IK) and in contact lens peripheral ulcers (CLPU) or the multiple, small-diffuse round white infiltrates seen 2-3 mm from the limbus in contact lens-associated red eye (CLARE).1 The eyes can be white to moderately injected with no corneal oedema and there is no overlying NaFl staining. Patient symptoms can range from none to acute burning, redness and photophobia, with some reporting prior milder episodes of hyperaemia that disappear when they give their eyes a break from contact lens wear.1

Fortunately, CLAIK can be treated without any long-term consequences. Because of its self-limiting nature, immediate lens cessation is a good place to start. Treatment can range from simple monitoring to prescribing topical ocular steroids, such as Lotemax or Pred Forte, or a combination antibiotic/steroid preparation, such as Tobradex, to decrease the microbial load. Once the signs and symptoms are resolved completely, wait at least eight days to see if the infiltrates reappear; if they do not, consider changing the lens care solution to another MPS or hydrogen peroxide system before loosening the fit or refitting to another SiHy or conventional hydrogel. Finish off with a discussion of lens hygiene and compliance or better yet, switch to a daily disposable lens without solution.1 

While it has been suggested that CLAIK may be associated with certain SiHy-MPS combinations, the non-consensus in clinical data make this debatable. Regardless of whether it is a growing problem or not, CLAIK is still a concern for the patient and the practitioner, especially if there are vision, ocular health and safety risks. Until we get definitive evidence that certain combinations of SiHy material and MPS cause CLAIK, it remains incumbent on the research community and lens product companies, in the interests of accurate diagnosis and appropriate risk management by eyecare professionals, to continue to investigate other aetiologies for CLAIK that might have been overlooked.


[i] SHOVLIN J, EIDEN S.B., et al. “Infiltrative keratitis in daily lens wearers: do you see what I see?” Contact Lens Spectrum. vol. 26, suppl, April 2011

[ii] SACCO A. “Contact Lens-Associated Infiltrative Keratitis and Multipurpose Solutions”. Contact Lens Spectrum. April 2011

[iii] KISLAN T.P., HOM M.M. “Corneal infiltrates with multipurpose solutions and contact lens combinations”. Investigative Ophthalmology & Visual Science vol. 51, suppl, May 2010, E-Abstract 3424

[iv] “Clinicians link contact lens-associated infiltrative keratitis to contact lens solution”, Ocular Surgery News,August 30, 2012.

[v] SZCZOTKA-FLYNN, Loretta B, CHALMERS, Robin. “Corneal Infiltrates: Managing Risks With Soft Lens Wear”, Contact Lens Spectrum. vol. 27, January 2012, p. 12-13

[vi] CHALMERS, R.L., MITCHELL, G.L., et al. “Age and other risk factors for corneal infiltrative and inflammatory events in young soft contact lens wearers from the Contact Lens Assessment in Youth (CLAY) Study”. Investigative Ophthalmology & Visual Science, vol. 52, no 9, August 2011, p. 6690-6

[vii] CARNT, N.A., EVANS, V.E., et al. “Contact lens-related adverse events and the silicone hydrogel lenses and daily wear care system “used”, Archives of Ophthalmology, vol. 127, no 12, December 2009, p. 1616-23

[viii] CHALMERS, R.L., McNALLY, J., et al. “Multi-center case control study of the role of lens materials and care products on the development of corneal infiltrates”, Optometry & Vision Science, vol. 89, no 3, March 2012, p. 316-25

[ix] CARNT, N., JALBERT, I., et al. “Solution toxicity in soft contact lens daily wear is associated with corneal inflammation”. Optometry Vision Science, vol. 84, no 4, April 2007, p. 309-15.

[x] KARPECKI, D. “The Science behind the Stain”. Contact Lens Spectrum, supp. October 2011

[xi] BAKKAR, May M. An investigation of solution-induced corneal staining using an in vitro model, A thesis submitted for the degree of Doctor of Philosophy (PhD) in the Faculty if Life Sciences, University of Manchester, UK, 2012, 244 p.

[xii] EFRON, N. “Contact lens induced changes in the anterior eye as observed in vivo with the confocal microscope”, Progress in Retinal & Eye Research, vol. 24, no 4, July 2007, p. 398-436

[xiii] OZKAN, J., MANDATHARA, P., et al. “Risk factors for corneal inflammatory and mechanical events with extended wear silicone hydrogel contact lenses”, Optometry & Vision Science, vol. 87, no 11, November 2010, p. 847-53

[xiv] SZCZOTKA-FLYNN, L., LASS, J.H., et al. “Risk factors for corneal infiltrative events during continuous wear of silicone hydrogel contact lenses”, Investigative Ophthalmology & Visual Science, vol 51, no 11, November 2010, p. 5421-30

Were You Out When Opportunity Knocked?

By Shirley Ha, BSc. (Hons), O.D.

As the online retail economy continues to grow, and as more people adopt mobile technology including smart phones and tablets[i], consumers will have greater opportunities to browse online and research optical products 24/7/365.

The December 2011 Vision Council Vision Watch Internet Influence Report stated that 26.7 per cent of 1,306 contact lens buyers surveyed in the U.S. used the Internet in some capacity when purchasing contact lenses; another 16.4 per cent purchased their lenses online. The two most influential forces cited by survey respondents were price and convenience[ii]. And as a result, bricks and mortar businesses lost sales revenue of about $604 million to online sources.

To minimize contact lens prescription walkouts, practitioners must build on or implement marketing strategies to improve retention of existing contact lens patients.

Educated Patients are Loyal Patients
Over the years, marketers have turned contact lenses into a commodity, which is why patients seek alternative retail outlets. Patients need to understand that contact lenses are medical devices that sit on the surface of the eyes to correct their vision. Emphasize that you want their eyes to be healthy, to work well together and to have normal field of vision. Besides the cornea, they need to understand that the lids, lashes, conjunctiva and tear film all need to be assessed periodically to ensure optimum vision, comfort, eye health and continued contact lens success.

Differentiate Yourself
Know and meet your patients’ lifestyle and visual needs. Market yourself as the go-to expert with access to a diverse product line, including specialty lenses for keratoconus, orthokeratology presbyopia and therapeutic uses that only you can customize for them. Upgrade as many existing patients as possible to newer-technology products and communicate the benefits for them to them.

Set Appropriate Fees
Competing with online providers who benefit from low overhead and high-volume purchases will get you nothing except a revenue shortfall. Be fair to yourself and to your patients. Don’t undervalue what you do but, at the same time, keep profit margins reasonable. Patients associate higher prices with higher quality products and exceptional service, but they look at the value they receive from the interaction, too. They want to buy from you; don’t give them a reason to shop elsewhere because of over-inflated prices.

Sell Annual Supplies
You should be selling annual supplies. Explain to patients the economic benefits of volume purchasing and manufacturer rebates, if available. If this doesn’t convince them, explain the health benefits of fresh lenses on the eyes when replaced in a timely manner. It is much better than extending the wear of their last pair and putting their eyes at risk for contact lens complications. Encourage patients to take an interest in their eye health and help them to realize how precious their eyes and good vision are.

Create a Digital Footprint
There is no denying it – both you and your patients spend time online for sports, games, news and information, entertainment, retail and/or social networking. During the week of Oct. 22, 2012, comScore’s survey of 1,989 U.S. respondents ranked “Retailer Websites” second, after “Online Search Engine”, as the most valuable tool for shopping[iii]. Yet, in a recent survey conducted by Breton Communications, fewer than three-quarters (74.2 per cent) of Canadian eyecare professionals reported having a website and 11.2 per cent had no Internet access in their offices[iv].

At the very least, create a business website and have a digital presence where your patients can seek you out. Be the person in front of your patients when they are on their smart phones commuting to and from work or on their tablets after dinner.

If you haven’t done so, consider getting on the social media bandwagon or create a blog and start building fans and followers who are interested in your products and services.

E-stores: To Have or Not?
This is a contentious topic for many practitioners but the reality is that in recent years, more and more practices have incorporated secured contact lens re-ordering platforms through their websites. This has enabled them to capture revenue that would have been lost to online suppliers, while making the contact lens sales process simpler and more convenient for their patients.

Your patients come to you for guidance and as a resource and will pay a premium if they perceive value in the services you provide. Your job as a practitioner/salesperson is to direct them towards a final sale with your reputable service. So make service your number one brand!


[i] WALL, Mike. “2012 Canada Digital Future in Focus: Trends Every Marketer Needs to Know”, comScore Webinar presentation, March 2012.

[ii] The Vision Council Research: December 2011 Vision Council VisionWatch Internet Influence Report.

[iii] FULGONI, Gian, LIPSMAN, Andrew, ESSLING, Ian. “The State of the U.S. Online Retail Economy in Q3 2012”, comScore Webinar presentation, November 2012.

[iv] SOMMERS, JoAnne. “Canada’s ECPs by the Numbers”, Envision: seeing beyond, November/December 2012, p. 8-18.

Seeing the Future with Augmented Contacts

By Shirley Ha, BSc. (Hons), O.D.

Imagine real-time data and information streaming in a mid-air, 3D interface (think Tony Stark in Iron Man). But instead of the heavy suit and headgear, it involves “smart” contact lenses that provide biofeedback and enhanced vision simultaneously.

Welcome to the future – a world of augmented reality featuring contact lenses that monitor your health, thanks to the melding of nanotechnology, biosensors and visual digital information that you can manipulate physically.

Sounds too futuristic? It’s not. Researchers and bioengineers around the world are working on these devices, including lenses that dispense medication1,2. Some even have stem cells growing on them.3 While many are still in the form of prototypes, others are awaiting or undergoing human clinical trials. And one is already on the market.

Switzerland’s SENSIMED Triggerfish®, with the Canadian distribution by Labtician Ophthalmics anticipated to begin around February 2013, is the first commercially available device that continuously monitors intraocular pressure (IOP) variances and provides a 24-hour IOP profile of a glaucoma suspect/patient.4 It consists of a single-use contact lens with “strain” sensors that measure changes in corneal curvature, along with a self-adhesive antenna around the eye and a portable recording device. The two to three annual recordings of when transient IOP peaks occur in a 24-hour period are intended to help the physician monitor and manage a patient’s personalized treatment plan. While it has been sanctioned by Health Canada, at the time of writing, the device was undergoing clinical trials (19 registered) in the U.S. and has not yet received the Food and Drug Administration’s approval.5,6

Another remarkable IOP-monitoring sensing technology comes from the University of California, Davis and uses a drop of liquid to gauge pressure. Like “smart gloves” that can give physicians the enhanced ability to measure firmness of tissues and detect tumors, the flexible sensor relies on the increase in capacitance at the electrode of a single droplet of liquid within a “smart” contact lens as it is pressed by the firmness of the cornea.7

In London, ON, Dr. Jin Zhang and her group at the University of Western Ontario developed sensors with nanostructured optical probes embedded in contact lenses that change colour, depending on the wearer’s biomarkers, i.e., glucose levels in the tear layer instead of in the blood.7,9 She hopes her innovation will become the, “safe, sensitive and cost-effective glucose diagnostic tool and monitoring solution,”10 for diabetics around the world and that it will be extended to help people with other chemical imbalances such as calcium and potassium.11

In May 2012, a team led by organic chemist Dr. Jun Hu at the University of Akron in Ohio announced a glucose-sensing coating containing a boronic acid derivative12 on their colour-changing contact lenses for diabetics. Because only one of the contact lenses worn will have the coating and can change colour, he is designing a smart phone application to record the colour difference and quantify the glucose levels.13

Instead of chemically induced colour-changing contact lenses, Dr. Babak Parviz at the University of Washington in Seattle and his international team of researchers used amperometric sensing to detect glucose levels in the tear film.14 His sensors measure changes in tiny currents through the tear layer between sets of electrodes. Early tests on rabbits showed they could accurately detect even very low glucose levels.

Dr. Parviz, a pioneer in “smart” contact lenses, and his team have also been working on computerized contact lenses with display technology. They have already proven they can shrink electronics and wirelessly power red and blue light-emitting diodes (LEDs) embedded in a contact lens.15 In November 2011, his team successfully activated their prototype electronic contact lens with an unfocused, single-pixel, blue LED on a live, anaesthetized rabbit eye with no adverse effects to the rabbit’s cornea. Unfortunately, while the researchers were able to power the lens from about one metre away in vitro, the distance dropped to about two centimetres in vivo. Dr. Parviz’s goal is to design a better focused, full-colour, higher-resolution display lens that uses internal or less energy to power.

These breakthroughs led Microsoft Research to partner with Dr. Parviz’s lab in December 2011. They are now developing a “functional” contact lens that will monitor blood sugar levels through tears and provide real-time feedback wirelessly to an external local device, with the eventual goal of merging Dr. Parviz’s technology to stream data seamlessly onto a person’s field of view.16

We can look forward to exciting times as researchers continue to add miniaturized capabilities to contact lenses with improving nanotechnology. From web surfing to navigating to up-to-date health and safety monitoring – the possibilities are endless. And all of this is without the need for physical headgears, electronic screens or communication devices. The future looks very bright indeed.

References:
1 PENG, C.C., BURKE, M.T., CHAUHAN, A. “Transport of Topical Anesthetics in Vitamin E Loaded Silicone Hydrogel Contact Lenses”, Langmuir, vol. 28, no 2, 2012, p.1478-87

2 TIEPPO, A., WHITE, C.J, PAINE, A.C, VOYLES, M.L, MCBRIDE, M.K, BYRNE, M.E, “Sustained in Vivo Release from Imprinted Therapeutic Contact Lenses”, Journal of Controlled Release, vol.157, no3, February 2012, p.391-7

3 Centre for Eye ResearchAustralia: News Archive. “Stem Cell Treated Contact Lenses to Repair Damaged Eyes”, June 2012. Available at: http://www.cera.org.au/news/61/124/2012-06-18/stem-cell-treated-contact-lenses-to-repair-damaged-eyes/?page=1 (Accessed August, 2012)

4 Company website. Sensimed AG. www.sensimed.ch (Accessed August 2012)

5 MANSOURI, K., WEINREB, R.N. “Meeting an Unmet Need in Glaucoma: Continuous 24-h Monitoring of Intraocular Pressure”, Expert Review of Medical Devices, vol. 9, no 3, May 2012, p. 225-31

6 ClinicalTrials.gov – a service of the National Institutes of Health. Search: Triggerfish. Available at: http://clinicaltrials.gov/ct2/results?term=triggerfish (Accessed September 2012)

7 NIE, B., XING, S., BRANDT, J.D., PAN, T. “Droplet-based Interfacial Capacitive Sensing”, Lab on a Chip, vol. 12, no. 6, 2012, p. 1110-1118

8 COLLIER, R. “Rosy Outlook for People with Diabetes”, Canadian Medical Association Journal, vol. 182, no 5, March 2010, p. E235-6

9 ZHANG, J., HODGE, W., HUTNICK, C., WANG, X. “Noninvasive Devices for Diabetes through Measuring Tear Glucose”, Journal of Diabetes Science and Technology, vol. 5, no 1, January 2011, p. 166-72

10 ZHANG, J. “Development of Non-invasive Diagnostic Device for Diabetes”, Canadian Rising Stars in Global Health – Round 1 Grantees, grandchallenges.ca, June 2011. Available at: http://www.grandchallenges.ca/canadianrisingstars_round1grantees/jinzhang_en/ (Accessed August 2012)

11 GILLESPIE, B. “Seeing Red”. Innovation.ca, July 2010. Available at: http://www.innovation.ca/en/ResearchInAction/ImpactStory/Seeingred (Accessed August 2012)

12 Patent: Optical Device and Method for Non-invasive Real-time Testing of Blood Sugar Levels. Available at: http://patentscope.wipo.int/search/en/detail.jsf?docId=WO2011034592&recNum=1&maxRec=&office=&prevFilter=&sortOption=&queryString=&tab=PCT+Biblio (Accessed August 2012)

13 BATES, C. “Colour-changing Contact Lens Could Replace Painful Skin Pricks for Diabetics”, May 2012. Available at: http://www.dailymail.co.uk/health/article-2149276/Colour-changing-contact-lenses-replace-painful-skin-prick-tests-diabetics.html (Accessed August 2012)

14 YAO, H., SHUM, A.J., COWAN, M., LAHDESMAKI, I., PARVIZ, B.A. “A Contact Lens with Embedded Sensor for Monitoring Tear Glucose Level”, Biosensors and Bioelectronics, vol. 26, no 7, March 2011, p. 3290-6

15 LINGLEY, R., ALI, M., LIAO, Y., MIRJALILI, R., KLONNER, M., SOPANEN, M., SUIHKONEN, S., SHEN, T., OTIS, B.P,. LIPSANEN, H., PARVIZ, B.A. “A Single Pixel Wireless Contact Lens Display”, Journal of Micromechanics and Microengineering, vol. 21, no 12, November 2011, p. 1-8

16 Microsoft Research. “Functional Contact Lens Monitors Blood Sugar Without Needles”,December 8, 2011. Available at: http://research.microsoft.com/en-us/collaboration/stories/functionalcontactlens.aspx (Accessed August 2012)

Tweens & Contact Lenses – Made for each other!

By Shirley Ha, BSc. (Hons), O.D.

makingcontactWho are tweens? According to Wikipedia, they are youths, usually between the ages of 8 and 12. These young people go through a transitional phase of self-awareness and discovery, peer pressure and social acceptance as they develop their independence and interact with others. At that stage, adding eyeglasses with their associated social stigma can be an overwhelming experience. Alternatively, adjunct contact lenses can provide tweens with additional benefits beyond simple vision correction for refractive errors.

A literature overview by the Faculty of Social and Behavioral Sciences at the University of Amsterdam showed that wearing eyeglasses negatively impacted how children felt about their physical appearance because of negative stereotyping by peers.[i] In a study of 585 tweens and teens, eyeglasses were also perceived as socially unacceptable, while contact lenses were the preferred ‘eye correction choice’ for school, sports activities and hanging out with friends.[ii]

When should practitioners start introducing contact lenses to tweens? In the Children & Contact Lenses study conducted by the American Optometric Association, more than half (51 per cent) of 576 optometrists surveyed felt that 10 to 12 years of age was appropriate, while 12 per cent felt that ages eight to nine were suitable.[iii]

Among tweens, emotional and social behaviour varies, so the question of when they should start wearing contact lenses is often not a matter of age. Rather, factors such as interest, motivation, hygiene, maturity and sense of responsibility in adhering to the care and wearing schedule will determine a tween’s suitability and probability of success.

The three-year multi-site Adolescent and Child Health Initiative to Encourage Vision Empowerment (ACHIEVE) Study from the Ohio State University College of Optometry revealed that myopic contact lens-wearing tweens felt significantly better about their physical appearance, social acceptance and athletic abilities than did tweens who wore eyeglasses. They also felt more confident about their academic performance if they initially disliked their eyeglasses.[iv]  A follow-up study concluded that tweens over the age of 10 who played sports, those who were motivated to wear contacts, and those who disliked wearing eyeglasses were the best candidates for contact lens wear.[v]

But can tweens handle contact lens care and wear once they pass the initial screening process? Several studies have supported the belief that tweens as young as eight are able to insert, remove and independently care for and wear contact lenses successfully.[vi],[vii] Similarly, the Contact Lenses In Pediatrics (CLIP) study of 84 tweens and 85 teens (13 to 17) showed that tweens were as compliant with contact lens care and wear instructions as teens.[viii]

There is also no evidence of increased eye health risk or harm for tweens wearing contact lenses. In the Contact Lens Assessment in Youth (CLAY) Study of 3,549 soft contact lens wearers, 8- to 15-year-olds had significantly fewer corneal infiltrative and inflammatory events (CIEs) than 15- to 25-years-olds.[ix] Another online survey showed that after 10 years of contact lens wear, 86 wearers fitted with contact lenses at age 12 or younger had similarly few adverse events, were as compliant, comfortable and successful as the 89 wearers fitted with contact lenses as teenagers.[x]

Tweens and teens have similar corneal anatomy and physiology.  They do not take more practice chair time to fit contact lenses and are shown to be as easy to fit as teens.

The trend to fit tweens with contact lenses is shifting. The advances in contact lens designs and materials are allowing eyecare practitioners to fit more children and tweens with contact lenses, especially daily disposables. Single use lenses are healthy, safe, simple, easy to handle and comfortable, and should be the first-time contact lens choice for tweens. 2,6 

Tweens are continually figuring out their identities and how they fit in with and contribute to society.  Even with today’s vast array of colourful and trendy frames, tweens welcome the prospect of contact lenses when given the opportunity. Although tweens make up a small percentage of your patient population, practitioners should ask about their interest in wearing contact lenses and never limit the choices available to them. Offer every tween and parent the option of selecting contact lenses as an alternative to eyeglasses. With parental approval and support, the social benefits, along with the known visual benefits and safety of contact lenses are undeniable.

Build on the excitement of that first fit and have tweens spread their enthusiasm to friends and family members. And don’t forget to prescribe appropriate sunglasses and eye protection for sports, too. Finally, what’s not to like about the revenue opportunities that happy parents and tweens offer you? They make for a winning combination.


[i] JELLESMA, F.C. “Do glasses change children’s perceptions? Effects of eyeglasses on peer- and self-perception”, European Journal of Developmental Psychology, July 2012, Volume 0, Issue 0, pp 1-12.

[ii] SILBERT, J.A. “Fitting Tweens and Teens with Daily Disposables”, Contact Lens Spectrum, April 2009.

[iii] Children & Contact Lenses: Doctors’ Attitudes & Practices in Fitting Children in Contacts, AOA Executive Summary, October 2010.

[iv] WALLINE, J.J., JONES, L.A., SINNOTT, L., CHITKARA, M., COFFEY, B., JACKSON, J.M., MANNY, R.E., RAH, M.J., PRINSTEIN, M.J., the ACHIEVE Study Group. “Randomized trial of the effect of contact lens wear on self-perception in children”, Optometry and Vision Science, March 2009, Volume 86, Issue 3, pp 222-32.

[v] RAH, M.J., WALLINE, J.J., JONES-JORDAN, L.A., SINNOTT, L.T., JACKSON, J.M., MANNY, R.E., COFFEY, B., LYONS, S.; the ACHIEVE Study Group.  “Vision Specific Quality of Life of Pediatric Contact Lens Wearers”, Optometry and Vision Science, August 2010, Volume 87, Issue 8, pp 560-6.

[vi] WALLINE, J.J., LONG, S., ZADNIK, K. “Daily Disposable Contact Lens Wear in Myopic Children”, Optometry and Vision Science, April 2004, Volume 81, Issue 4, pp 255-9.

[vii] WALLINE, J.J., GAUME, A., JONES, L.A., RAH, M.J., MANNY, R.E., BERNTSEN, D.A., CHITKARA, M., KIM, A., QUINN, N. “Benefits of Contact Lens Wear for Children and Teens”, Eye Contact Lens, November 2007, Volume 33, Issue 6, Part 1 of 2, pp 317-21.

[viii] WALLINE, J.J., JONES, L.A., RAH, M.J., MANNY, R.E., BERNTSEN, D.A., CHITKARA, M., GAUME, A., KIM, A., QUINN, N., and THE CLIP STUDY GROUP. “Contact Lenses in Pediatrics (CLIP) Study: Chair Time and Ocular Health”, Optometry and Vision Science, September 2007, Volume 84, pp 896-902

[ix] CHALMERS, R.L., WAGNER, H., MITCHELL, L., LAM, D.Y., KINOSHITA, B.T., JANSEN, M.E., RICHDALE, K., SORBARA, L., MCMAHON, T.T.  “Age and Other Risk Factors for Corneal Infiltrative and Inflammatory Events in Young Soft Contact Lens Wearers from the Contact Lens Assessment in Youth (CLAY) Study”, Investigative Ophthalmology & Vision Science, August 2011, Volume 52, no. 9, pp 6690-6.

[x] WALLINE, J.J., EMCH, A.J., LAUL, A., REUTER, K., NICHOLS, J.J. Comparison of success in contact lens wearers fitted as children vs teenagers, ARVO poster May 2011.

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The Problem of Non-Compliance

By Shirley Ha, BSc. (Hons), O.D.

makingcontact

 

Despite growing awareness that improper contact lens care and wear procedures can significantly increase the risk of eye infections, many consumers still do not follow the manufacturer or practitioner’s recommendations for safe practices.

According to a University of Texas survey of 433 contact lens wearers, more than 50 per cent of participants were able to name contact lens-related complications. Yet only 2 per cent demonstrated ‘good’ compliance and only 1 participant was ‘fully’ compliant. At the same time, 85 per cent of participants believed they practiced safe lens, solution and case handling.[i]

The non-compliant behaviors cited were:

 

  • Swimming (64 per cent) and exposure to tap water, including showering (57 per cent) while wearing lenses
  • Sleeping while wearing lenses not intended for continuous wear (56 per cent)
  • Failure to adhere to the recommended wearing schedule (52 per cent)
  • Not washing hands prior to handling lenses (49 per cent)
  • Never replacing lens case or replacing them only if given a new case (47 per cent)
  • Topping up (42 per cent) or re-using (28 per cent) disinfectant solutions

Interestingly, ‘comfort and handling’ was cited as a complication more often than infection – and although 90 per cent of study participants were aware of the importance of using fresh solution, many failed to discard used solution first.

In another study, 20 per cent of patients polled in the UK admitted that they used tap water, saliva, baby oil, beer, Coke, petroleum jelly, lemonade, fruit juice and butter (!) as alternatives to contact lens solutions (Bausch + Lomb news release, Nov. 2011).

In recent years, a plethora of industry-sponsored research papers have discussed contact lens care compliance relating to solutions, wearing modality and ocular lubricants.[ii] However, in developing safer, more effective and easier-to-use disinfection systems and more comfortable, oxygen-permeable lenses, manufacturers could inadvertently be sending a false message that it is ‘safe’ to stretch lens wear longer than indicated or to sleep in lenses more often than recommended.

In comparison with these findings, about 350 eyecare practitioners surveyed by Contact Lens Spectrum for the 2011 Annual Contact Lens Report believed that 75 per cent of their patients wash their hands before handling their lenses, that 60 per cent rub their lenses and 64 per cent rinse them as recommended; they also believed that 70 per cent of their patients followed recommended contact lens hygiene guidelines.[iii]

So, why the discrepancy between practitioner perception and patient performance?  Are patients lying to their practitioners about lens hygiene and solution handling?

To cultivate compliance, the gold standard has always been to use auditory and visual patient education aids to address personal hygiene or hand washing, wearing and replacement schedule[iv],[v] , cleaning and disinfection of lenses and storage cases , and to discuss adverse contact lens-related events such as potential corneal complications. Yet, a significant majority of patients continue to demonstrate non-compliance despite awareness of the risks.[vi]

Dr. Gary Gerber, a New Jersey-based practice building expert-optometrist and president and founder of Power Practice®, agrees that not all aspects of patient education work to improve compliance: “We know that showing patients an ulcerated cornea or the classic nasty red eye poster doesn’t work. Education about what patients lose when they are non-compliant resonates better. So, talk to patients about the reasons they love wearing lenses (freedom, self-confidence) and remind them that if they blow it, they lose all that. In other words, talk about the loss of benefits and advantages – not the features of the lenses.”

It remains incumbent on practitioners to keep providing appropriate patient education, instruction and training in order to increase patient vigilance about the risks associated with contact lens wear. Equally important are regular follow-up visits to determine whether they are compliant with the recommended wearing and replacement schedule and to ascertain whether patients are conforming to the accepted lens, solution and lens case care guidelines.

Standardizing a set of questions to elicit non-compliant behaviors and repeating professional advice at each follow-up visit can help practitioners augment compliance and reinforce the importance of good lens and solution handling practices. Be aware that the questions, depending on how they are formulated, may also generate false responses from patients, especially from those who don’t want to admit to improper lens wear and care.  As an example, ask patients what happens in the morning after they have slept in their lenses instead of asking whether they sleep overnight in their lenses.

Not all contact lens-related problems are the result of poor compliance and there is no quick fix for patient non-compliance. The problem is not going to disappear anytime soon but by recognizing the different kinds of non-compliant behaviors, providing appropriate education and training, asking the right questions at follow-up visits, and delivering the consistent message of continued commitment to good lens, solution and lens case hygiene, practitioners can help carve a safe and healthy path to clean, clear and comfortable vision for all contact lens patients.

 


[i] ROBERTSON, DM, CAVANAGH, HD. Non-Compliance with Contact Lens Wear and Care Practices: a Comparative Analysis Optometry & Vision Science, December 2011, volume 88, pp1402-1408

[ii] GROMACKI, SJ. Research From the 2011 AAO Annual Meeting, Contact Lens Spectrum, December 2011

[iii] NICHOLS, JJ. Contact Lenses 2011, Contact Lens Spectrum, January 2012

[iv] HICKSON-CURRAN, SB. Compliance Before, During and After Contact Lens Wear, Contact Lens Spectrum, January 2012

[v] BENOIT, DP. Compliance and Contact Lenses, Contact Lens Spectrum, May 2011

[vi] BUI, TH, CAVANAGH, HD, ROBERTSON, DM. Patient Compliance During Contact Lens Wear: Perceptions, Awareness, and Behavior., Eye & Contact Lens, November 2010, volume 36, issue 6

Daily Disposable Contact Lenses: The Good, the Bad and the Reasons Why

By Evra Taylor

makingcontact

There is no doubt that we live in a disposable society. In contrast to earlier times when excellent craftsmanship meant product durability, nowadays our first response when something has served its purpose is to get rid of it. This is true for a diverse range of products from personal razors to computers, whose built-in obsolescence boosts manufacturers’ profits.

While some people would describe the phenomenon of “disposability versus longevity” as negative, in some instances, modern technology has led to manufacturing breakthroughs that translate into greater consumer convenience. Daily disposable contact lenses are one example of this.

Overview

In 1994, Johnson & Johnson introduced ACUVUE® – the first daily disposable contact lenses in the U.S. Contact lens technology has progressed significantly since then. Now, even toric lenses for the correction of astigmatism as well as bifocals are available in daily disposable format.

Daily disposable contact lenses are ideal for occasional use such as playing sports or for special events involving one-time use – like a wedding – where replacing eyeglasses with contact lenses is an important cosmetic consideration. These lenses are also a good choice for people who combine contact lens wear with spectacle use. Some of today’s disposable lenses are made of the same materials as traditional lenses; other disposables are made from new materials developed specially for this purpose.

An important advance in the technology of these lenses is that they are now offered in a broader sphere power range than ever before, from +8.00D to -12.00D. In addition, some lenses offer diameters surpassing 14 mm, which makes them available to a greater number of patients.

Advantages

Daily disposable contact lenses provide several advantages, the chief of which is convenience. Since contact care, cleaning and disinfection are not required with daily disposables they provide a measure of ease of wear.

Daily disposables also offer a number of key “ingredients” that practitioners look for in a high-performance lens, including low rotation (which is of value with toric lenses), lens stability and high oxygen transmissibility.

Daily disposables are thought to reduce the risk of protein deposits, eye infections caused by the lenses or the solutions used to clean them – including fungal keratitis and Acanthamoeba keratitis – and eye ulcers. Since they are replaced daily, the time for deposits like proteins and allergens to build up on the lenses is reduced. Moreover, many of these lenses offer some protection from UV rays, which is particularly relevant for patients who play sports. However, it should be noted that the UV protection does not protect the bulbar conjunctiva which means that daily disposables do not eliminate the need for the eye protection afforded by proper sunglasses.

Although toss-away lenses are perceived as expensive, they eliminate the need for contact lens solution and, more importantly, the contact lens case, which is a significant risk if not disposed of at least once every two to three months.

Some practitioners maintain that the difference in the cost of disposable contacts compared to that of traditional contact lenses is minimal and is offset, at least in part, by the reduced need for cleaning products.

Disadvantages 

Daily disposable lenses might not be available for certain uncommon prescriptions, and certain specialty soft contact lenses, such as color contacts and theatrical contact lenses, are not available in daily disposable form.

Complications due to contact lens wear are estimated at five percent of contact lens wearers each year.Most of these situations arise from non-compliance with the prescribed wear schedule, not using solutions properly, improper maintenance of lens cases or failing to dispose of cases at least every three months. It is crucial that eyecare practitioners discuss the importance of compliance when counselling patients on contact lens wear.

Daily disposable contact lenses represent a positive advance in terms of patient convenience and comfort and may, in fact, constitute a large portion of your practice. However, they are not without drawbacks and patients should be presented with “the whole truth and nothing but the truth” when it comes to their use.