MULTIFOCAL CONTACT LENSES
SiHy Multifocal Contact Lenses Can Maximize Eye Health
Dry eye symptoms, which affect millions of patients, can be minimized with the newest silicone hydrogel multifocal contact lenses.
By Glenda Secor, OD, FAAO
It's our fault. It's our fault that patients' eyes don't work like they used to, that they feel drier and are more intolerant of their beloved contact lenses. Baby boomers and folks who are part of Generation X are middle-aged, maybe not emotionally, but certainly chronologically. Their bodies are different and their eyes are different. Being able to address the issues of presbyopic contact lens wearers will reduce unnecessary dropouts, increase success with multifocal lenses and increase practice revenue. The opportunity is huge, thanks to age demographics and a plethora of contact lens options.
The presbyopic population is growing faster than any other demographic group. The numbers will swell to more than 60 million over the next few years.1 Their experience with new technology, from cell phones to computers, has influenced their needs and demands.
Contact lens-associated dry eye is a huge problem for many contact lens wearers, and it's especially complex for presbyopic patients.2-3 Many patients have a limited vocabulary when it comes to describing their discomfort and other issues that fall under the umbrella of "dryness." We know there's a direct relationship between contact lens success and how expeditiously practitioners respond to these complaints. These seemingly insignificant issues won't become catastrophic if addressed promptly. Unaddressed dissatisfaction could result in discouragement and eventual abandonment of contact lenses — a lose-lose situation.
The good news is that we have hope. Never in eyecare history has our armamentarium been as vast as it is today. We have better lenses, care products, medical management and clinical skills to enhance success. Although we can't cure dry eye, we can certainly improve comfort.
Silicone hydrogel lenses have demonstrated superior performance in symptomatic patients in numerous studies that documented improved comfort.4-5 An annual worldwide survey by Morgan and colleagues indicated the lenses have been widely accepted for the past 10 years, and their preeminence as the standard of care for lens materials has now evolved into multifocal designs. When compared with HEMA materials, the reduction in the water content of silicone hydrogels has resulted in reduced lens dehydration. The increase in silicone is also responsible for transmitting more oxygen, and this has reduced corneal hypoxia. These factors have the key subjective benefit of reducing red eyes and the key objective benefit of eliminating corneal hypoxia and neovascularization.
Another key area of success with silicone hydrogels is the reduction of protein deposits on the lens surface. The prelens tear film plays a key role in contact lens comfort. The ability to maintain tear film stability is imperative to prevent bacterial and debris adherence to the lens surface. The amassing of unwanted by-products on the ocular surface can contribute to increased discomfort, inflammation and/or infection.
Now that multifocal lens designs are available in silicone hydrogel materials, the superior core benefits of the new lenses make them our first choice, since they�re already available in spherical and toric designs.6
CARE PRODUCTS AND COMPLIANCE: HOW THEY IMPACT COMFORT
Simple compliance reinforcements, such as on-time observance of recommended lens replacement schedules and proper care and product usage, can reduce discomfort. Solution-induced corneal staining has been reported with several staining grids and the response appears to be formulation- and time-dependent. Hydrogen peroxide disinfection is superior to multipurpose products in a compromised environment.7 The absence of preservatives in hydrogen peroxide disinfection systems makes their use worth the additional effort because the outcome is improved wearing time, reduction in symptoms and a healthier ocular environment. Regardless of prescribed modality, clean hands, clean lenses and clean cases all enhance success.
Many non-contact lens-related reasons for reported dryness symptoms are outside of our control. For example, ocular dryness has been associated with certain classes of systemic medications, such as antidepressants, oral antihistamines and antihypertensives. Autoimmune diseases and menopause are especially problematic for presbyopic women who dominate our multifocal contact lens market.8 We work and play in dry environments and have multifaceted lifestyles that increase the physical demands on our tear film. Although we have a limited opportunity to influence these areas, an open discussion may reduce some of the anxiety expressed by symptomatic patients.
The presence of lid disease and its management probably will have the most significant non-contact lens-related impact on your multifocal success.9 All blepharitis must be treated. Meibomian gland dysfunction and lipid tear layer issues are integral players in evaporative dry eye conditions. The lipid-deficient eye has an unstable tear film, and the compromised lubricity results in an unstable tear film. The mechanical effects from irritants, such as lid wiper epitheliopathy, will lead to micro-traumatic-driven inflammation.10 This diminishing cascade can be the missing link when assessing signs and symptoms.
Preemptive treatment plans to improve lid hygiene include daily hot compresses and eyelid cleaners, combined with digital expression of meibomian glands. Oral doxycycline and topical azithromycin applied to lid margins can result in dramatic improvement in ocular well-being.11
The 2007 Report of the International Dry Eye Workshop classified the multifactorial nature of dry eye disease, its effect on the ocular surface environment and recommended management strategies.12 We know that signs and symptoms rarely equal the visual disturbance and subjective distress that accompany this symptom-based eye disease due to tear film instability. The inflammatory effects of meibomian gland dysfunction produce biomarkers of ocular surface disease. While ocular pro-inflammatory cytokine profiles can drive our diagnosis and treatment plans, a patient's history is still the gold standard for diagnosis. The symptoms reported by patients should reflect any responses elicited on subjective questionnaires, such as the ocular surface disease index.13 A thorough history, combined with a well-equipped toolbox of dry-eye management and contact lens options, is critically important for multifocal contact lens success. Although we don't have a single predictive test, assessing the subjective symptoms and the objective clinical signs in the eye will be the most predictive.
CURRENT ANTI-INFLAMMATORY THERAPY
One of the best tools in ocular surface disease management toolbox is the use of vital stains. Lissamine green has replaced rose bengal as the best objective diagnostic dry eye test. Lissamine green and rose bengal stains reveal tear proteins that are devoid of mucus, which is a hallmark sign of evaporative dry eye. Checking tear meniscus and performing tear breakup time and phenol red thread tests reduce practitioner anxiety over treatment plans.14
Cytokines are tear proteins that are biomarkers for ocular surface disease and inflammation. Topical antiinflammatory therapy downregulates cyotokines and can dramatically restore a disrupted corneal epithelium. Steroids rapidly repair the integrity of the tear film by treating the inflammatory component of dry eye disease.15 The fairly rapid relief provided by topical corticosteroids makes them a frequent choice of practitioners desiring a faster method to reduce symptoms. Cyclosporine A (Restasis, Allergan) is an immunomodulatory agent. It was the first drug approved by FDA to improve tear production and increase lacrimation when delivered in a topical application. Because it may take up to 6 months for cyclosporine to be clinically effective, therapy often begins with topical steroids as a pretreatment. Pretreating with "site-active" steroids, such as loteprednol (Lotemax, Bausch + Lomb) 0.5%, for 2 weeks before beginning treatment with cyclosporine may improve tolerance and enhance the beneficial effects of both medicines.16-17
Dietary supplements of essential fatty acids were serendipitously found to offer significant beneficial outcomes for inflammatory-induced dry eye patients. Omega 3 formulations, such as flax seed and fish oils, aren't drugs but have a therapeutic, long-term effect. In fact, patients who increase their tuna consumption will decrease their risk of dry eye.18
Another core management strategy in all stages of dry eye severity is additional ocular lubrication with and without lens usage. As with care products, reducing preservative exposure in artificial tear products enhances the effect with frequent instillation. But viscous gel supplements that augment a marginal tear film are better with bedtime usage when lenses aren't at risk of filming. Lacrimal and punctal plugs are great adjuncts to treatment plans because they reduce dependency on the patient to remember to use additional external lubrication.19
One of the most important ocular components of multifocal lens success is pupil size. Optimum size isn't too large or too small. Either extreme will limit optimum lens performance. Pupil size and reactivity also seem to diminish with aging, and this complicates multifocal lens effectiveness.
We all know about the "20/happy" visual acuity test for presbyopic patients. Binocular visual acuity replicates realworld experiences. Adherence to fitting guide recommendations will simplify our decision-making when modifications are needed. Optimal lens fit is mandatory for multifocal success. A poorly fit lens won't keep the optical portion centered properly and could hinder the patient's ability to appreciate multifocal vision. Having diagnostic experience with a minimum of two different multifocal lens designs will help you revise your treatment plan if the initial fit fails to perform optimally and changes must be made.
In the Austin Powers movies, the main character was slow to adapt to change. Practitioners who don't move away from yesterday's lenses — and learn to embrace change — are at risk of failure. The epidemic of presbyopia has created a competitive landscape for astute practitioners to embrace the fundamental superiority of silicone hydrogel multifocal lenses and maximize success.
|DR. SECOR IS IN PRIVATE PRACTICE IN HUNTINGTON BEACH, CALIF. A FELLOW OF THE AMERICAN ACADEMY OF OPTOMETRY AND DIPLOMATE OF THE CORNEA AND CONTACT LENS SECTION, SHE IS A PAST CHAIR OF THE CORNEA AND CONTACT LENS SECTION. SHE HAS WORKED WITH ALCON, AMO, ALLERGAN, BAUSCH + LOMB, CIBA VISION AND VISTAKON AS AN ADVISOR AND CLINICAL INVESTIGATOR.|
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