Multifocal Contact Lens Success: Fact or Fiction?
Investigating the prevailing notion that multifocal contact lenses do not work.
By Amy Dinardo, OD, MBA, FAAO, & Trevor Fosso, BS, BA
Despite advances in technology and an increased variety of multifocal contact lenses available, only one-half of contact lens-wearing presbyopes are prescribed multifocal lenses. Forty percent are fitted with non-presbyopic lens options, such as single-vision contact lenses in conjunction with reading glasses (Morgan et al, 2014).
This begs the question: Why do practitioners and/or patients continue to shy away from multifocal contact lenses? The cause is likely multifactorial. Some individuals express concerns about unnecessary visual compromise. Others mention a perceived lack of optimal multifocal lens designs in terms of comfort, cost, and visual performance. Lens fitters may fear patient dissatisfaction or dropout with multifocal lenses, resulting in decreased patient confidence in their practitioner (Morgan et al, 2014; Bennett, 2008).
Ultimately, the source of decreased multifocal lens use pertains, at least in part, to the notion that patients cannot be truly successful wearing multifocal contact lenses. However, does this belief arise from evidence-based facts or from unsubstantiated misconceptions?
Looking Deeper Into Multifocal Contact Lenses
The contact lens team of the Vision Research Institute (VRI) at the Michigan College of Optometry (MCO) designed a small pilot study to examine the commonalities among 20 patients who consider themselves successful multifocal lens wearers. The research protocol was approved by the Institutional Review Board (IRB) at Ferris State University. Researchers followed the tenets of the Declaration of Helsinki, and informed consent was given by all patients. We analyzed multiple factors, including contact lens use patterns, visual demands, visual acuity, contrast sensitivity, refractive error, personality, and quality of life (Table 1, Dinardo et al, 2014).
|Distance vision rating (1-5)*||4.30||±0.83|
|Intermediate vision rating (1-5)*||4.31||±0.55|
|Near vision rating (1-5)*||3.89||±0.83|
|Daily comfort rating (1-5)*||4.48||±0.58|
|Wear time (maximum)||5.4 days/week (soft), 6.5 days/week (GP)||±1.96 (soft)|
|Average hours per day||10.1 (soft)||±3.2 (soft)|
|13.6 (GP)||±4.1 (GP)|
|* Ratings based on a five-point visual analog scale|
We were surprised to discover that, while there are some unfortunate truths about multifocal lenses, not all of what eyecare practitioners assume about the multifocal contact lens experience is completely true. Furthermore, other well-respected researchers have evidence that debunks multifocal lens myths in support of using these types of lenses.
Let’s take a closer look at 10 myths about multifocal contact lenses.
Myth #1: Overall quality of vision prevents patients from wearing multifocal contact lenses successfully.
Fiction Simultaneous-vision multifocal contact lenses increase depth of focus by creating multiple overlapping focal points. This inherently creates a competition between focused and unfocused retinal images. Ideally, the patient’s brain chooses to view in-focus stimuli rather than the out-of-focus images. Theoretically, the in-focus image will still exhibit reduced contrast due to the superimposed out-of-focus image.
Evidence suggests that not all multifocal lens designs are created equal. Variances in power profiles can greatly affect lens performance (Plainis, Atchison, et al, 2013) (Figure 1). This—combined with factors such as the eyes’ inherent aberrations, pupil size, lens decentration, and movement—makes it reasonable to assume that the quality of vision is inferior to glasses.
Figure 1. Not all multifocal lenses are created equal. Various multifocal lens designs as imaged by the Nimo TR1504 (Lambda-X s.a.).
Recent studies evaluating the performance of modern multifocal lens designs show that patients achieve excellent high-contrast distance and near visual acuity of 20/20 or better, losing only a few letters of acuity compared to with spectacles. Multifocal lenses, however, do not perform quite as well in terms of low contrast and low illumination. Under these situations, patients tend to lose up to one line of acuity compared to spectacles (Richdale et al, 2006; Situ et al, 2003; Gupta et al, 2009; Woods et al, 2009; and others. Full list available at www.clspectrum.com/references.). The findings of the MCO-VRI study of successful multifocal lens wearers agrees with this research. On average, patients achieved high-contrast distance and near acuity equivalent to that of best-corrected spectacles with a Snellen equivalent of 20/20 or better. Low-contrast acuity decreased to a similar degree. Patients were not tested in low illumination (Dinardo et al, 2014).
While the loss of acuity with poor contrast and illumination is statistically significant in most studies, some question whether it is always clinically significant to patients. Reports suggest that patients generally score their multifocal lens experience highly, rating them just as good if not better than other options such as spectacles or monovision (Fernandes et al, 2013; Gispets et al, 2011; Richdale et al, 2006; Gupta et al, 2009; and others). Indeed, only 22% of the successful patients in the MCO-VRI multifocal study preferred the vision with their glasses over their contact lenses (Dinardo et al, 2014). The literature indicates that patients wearing multifocal lenses tend to be less satisfied with near vision compared to intermediate and distance vision. This was also true of the MCO-VRI multifocal lens study, albeit not statistically significant.
It is true that the primary reason cited for multifocal lens dropout is blurred or insufficient vision. There have been many documented instances in which, although patients perform extremely well with objective visual acuity testing in office, they still report symptoms such as glare, halos, and decreased contrast sensitivity (Gispets et al, 2011; Papas et al, 2009). This is why it is critical to avoid conventional methods of visual acuity testing when fitting multifocal lenses. Instead, directly assess distance, intermediate, and near vision by asking patients to view common objects such as street signs, faces, computers, magazines, and electronic devices. Ultimately, a patient’s subjective feedback after multiple days of wear in “real life” scenarios will help in assessing and troubleshooting the lenses.
Myth #2: Monovision is superior to multifocal contact lenses.
Fiction Studies that directly compare the two modalities argue that multifocal contact lenses provide the same, if not superior, visual acuity and contrast sensitivity in most instances when compared to monovision (Richdale et al, 2006, Situ et al, 2003, Gupta et al, 2009; Back et al, 1989; and others). Furthermore, significantly reduced stereopsis with monovision can lead to decreased visual acuity and contrast, challenges in performing daily tasks, and, ultimately, increased contact lens dropouts (Back, 1995).
Multifocal lenses are preferred by a majority of patients and practitioners alike. Modern research suggests that three out of every four patients prefer multifocal lenses over monovision (Richdale et al, 2006; Situ et al, 2003; Woods et al, 2009). At the first American Optometric Association (AOA) Contact Lens Summit in 2014, 85% of practitioners reported that they preferred multifocals for their patients (AOA Cornea and Contact Lens Section, 2014). Internationally, only 10% of presbyopic lens wearers are fitted in monovision (Morgan et al, 2014). This clear preference for multifocals can be attributed to qualities such as increased stereoacuity, range of near vision, and vision-related quality of life (Richdale et al, 2006, Situ et al, 2003, Gupta et al, 2009; Back et al, 1989; and others).
Certain lens designs or the choice of unequal add powers provide patients with “modified monovision.” This type of correction may be related to increased patient satisfaction because it increases patients’ range of clear vision while partially preserving stereoacuity (Bennett, 2008; Richdale et al, 2006). Indeed, exactly 50% of the successful patients in the MCO-VRI multifocal contact lens success study presented with some form of modified monovision (Dinardo et al, 2014).
Myth #3: Presbyopic patients who have moderate-to-high vision demands are not suitable candidates for presbyopic contact lenses.
Fiction There are few studies that directly examine patient satisfaction with specific visually demanding tasks. Gispets et al (2011) evaluated task-oriented visual satisfaction with two types of simultaneous-vision soft contact lenses. They reported decreased visual satisfaction when patients performed prolonged tasks involving higher visual demands at both distance and near. This included activities such as driving, reading, and writing. Patients reported higher visual satisfaction while performing activities at an intermediate distance or at a combination of distance and near vision activities. Examples given were computer work, household chores, or attending meetings.
The MCO-VRI study of successful multifocal lens patients found that a majority of subjects had occupations or hobbies with moderate-to-high near vision demands based on their reports of habitual activities. Occupations included clerical workers, educators, and accountants. Routine daily tasks included high levels of reading and using computers and other electronic devices (Dinardo et al, 2014).
Although not considered multifocal lenses in the purest sense, but rather bifocal/trifocal lenses, experts agree that translating contact lens designs are an excellent presbyopic lens option for mature presbyopes or for discerning patients who have critical distance and near vision demands (Bennett, 2008; Terry, 2011; Caroline and André, 2007; Bennett and Quinn, 2014). Clinical studies suggest that presbyopes wearing translating lens designs enjoy increased satisfaction (as high as 84%), good vision, comfort, and lens wettability (Norman, 2009; Norman and Peyre, 2010).
Regardless of the lens design being used, it is always a good idea to ask patients to describe and prioritize their daily activities and visual demands at all distances. This will assist practitioners in choosing the right lens design for optimal visual performance.
Myth #4: Advanced presbyopes are suboptimal candidates for multifocal lens wear.
Mostly Fact There has been speculation that multifocal lenses with high add powers underperform compared to those with low add powers. This supposition appears to be valid. Gupta and colleagues (2009) found that, for one particular simultaneous-vision center-near soft lens, a high addition produced poorer distance and near contrast sensitivity and reduced near visual acuity compared to its low-addition counterpart. Decreased visual performance became even more noticeable for high add powers under low lighting conditions. A separate study using a different center-near soft lens design showed that depth of focus decreased as add powers increased (Cox et al, 1993).
The natural decrease in pupil size with age can affect the performance of simultaneous-vision multifocal lenses in terms of limiting the functionality of their optical zone (Fernandes et al, 2013). In contrast, Plainis, Ntzilepis, and colleagues (2013) argue that decreased pupil size not only enhances multifocal lens performance by increasing depth of focus, but may also limit visual degradation from multifocal lens decentration (Figure 2).
Figure 2. Multifocal lens decentration away from the visual axis has been known to play a role in lens performance. The role of pupil sizes in terms of multifocal lens performance is still debated.
It is important to remember that while advanced presbyopes may be suboptimal candidates, this does not mean that they cannot be successful in multifocal contact lenses. With the right coaching and choice of lens design, advanced presbyopes can, and do, achieve satisfaction. In the MCO-VRI multifocal lens study, a majority of the successful contact lens patients were, in fact, advanced presbyopes who had adds greater than +2.00D (Dinardo et al, 2014). Other clinical research evaluating the performance of specific lens designs suggests that advanced presbyopes do achieve reasonably good visual outcomes with presbyopic lens designs (Gromacki et al, 2001; Johnson, 2005). Certainly, more research in this area is necessary.
Myth #5: If patients must wear readers over their multifocal contact lenses, they are not successful.
Fiction According to the MCO-VRI multifocal lens study, 25% of successful multifocal lens wearers utilize readers over their contact lenses occasionally to frequently. Furthermore, those who wore readers in this manner did not seem to mind (Dinardo et al, 2014).
In reality, factors such as pupil size, low illumination, and low contrast will negatively affect the visual performance of multifocal contact lenses. Richdale et al (2006) agree that the occasional use of reading glasses or an alternative method of correction for patients is not unreasonable, especially for difficult near tasks for prolonged periods of time.
Patient education to this effect is key when setting expectations. According to Bennett (2008), it is important to “under promise and over deliver” when it comes to multifocal contact lenses. Informing patients that they will be 100% free from glasses is unrealistic, and it sets patients up for failure. Instead, inform patients that, although most visual tasks should be comfortable for a large majority of the time, there will be some instances in which reading glasses worn over the contact lenses will be necessary (Bennett, 2008). Patients who come to accept this fact tend to have better outcomes. Also, if patients find that they do not have to wear reading glasses as much as they expected, they are pleasantly surprised instead of dismayed.
Myth #6: Motivation and personality affect multifocal contact lens success.
Fact Because they require some level of adaptation and visual compromise, multifocal contact lenses are more successful for patients who have high levels of commitment and motivation (Fernandes et al, 2013). In fact, motivation is one of the most important factors in achieving successful outcomes. It should be factored into the patient selection process when considering whether a patient is a good multifocal contact lens candidate (Bennett, 2008). Additionally, motivation can be reinforced at follow-up encounters when eyecare practitioners emphasize the positive aspects of lens wear, such as improved cosmesis and freedom from glasses.
A few studies have attempted to link personality traits to factors such as refractive error and blur tolerance (Godtland, 2012; Woods et al, 2010). To date, the MCO-VRI study is the first to examine personality traits as they relate to multifocal contact lens success. Participants completed the NEO-Five Factor Inventory-3 personality survey. It categorizes personality based on five taxonomies: neuroticism, extraversion, openness to experience, agreeableness, and conscientiousness (McCrae and Costa, 2010). Results, as reflected in Table 2, suggest that patients who are successful in multifocal contact lenses are organized, vigilant, and have a strong desire to achieve. Some may even be considered workaholics or perfectionists. These patients are also curious and sociable. They are open to new experiences and find novelty attractive.
|Neuroticism||Low-average||Even-tempered, low anxiety|
|Openness to experiences||High||Curiosity and appreciation for new ideas and experiences|
|Agreeableness||High-average||Compassionate, eager to please|
|Conscientiousness||High||Desire to succeed, perfectionist, vigilant|
|* Results as compared to a normative database (McCrae and Costa, 2010)|
Bottom line: Successful multifocal lens wearers are not necessarily patients who have personalities that you might expect to lead to blur tolerance. On the contrary, these patients can be quite discerning. However, if they are motivated to wear the lenses, successful multifocal contact lens wearers exhibit the patience and determination necessary to succeed.
Myth #7: Patients who have a history of contact lens wear are more successful with multifocal lenses.
Not Entirely Fact Hurdles such as transient blur and discomfort are more common in new contact lens wearers and may complicate the multifocal fitting process. Unfamiliarity with lens care and handling may also lead to some level of apprehension or frustration compared to experienced lens wearers (Bennett, 2008, Richdale et al, 2006). However, novice contact lens wearers should not be disregarded, especially if they are motivated to succeed. Researchers at MCO found that almost half of subjects who considered themselves successful in multifocal lenses were first-time contact lens wearers (Dinardo et al, 2014).
Myth #8: Patients who have dry eye symptoms or discomfort will not be successful multifocal lens wearers.
Fiction Along with decreased visual acuity, contact lens discomfort is another player in terms of why presbyopic patients discontinue lens use. Many times, this discomfort is associated with dry eye and ocular surface disease, which are not rare in the presbyopic population. The reasons behind contact lens discomfort are not completely understood. Aside from certain types of presbyopic GP lenses, there is no definitive evidence to suggest that multifocal contact lenses induce more discomfort and/or dry eye compared to other types of contact lenses (Jones et al, 2013).
In the MCO-VRI multifocal lens study, many patients showed signs of mild-to-moderate dry eyes, including decreased tear breakup time and mild-to-moderate levels of fluorescein and lissamine green staining on the anterior surface. Additionally, 80% of successful multifocal lens wearers reported using rewetting/lubricating drops occasionally or frequently. Yet, on average, patients rated the comfort in their contact lenses as 4.5 (±0.50) on a five-point visual analog scale (Dinardo et al, 2013). This implies that many patients experience some level of dry eye and discomfort while wearing their contact lenses, yet it is not enough to make them unhappy. They are either asymptomatic or have found methods with which to battle the symptoms. To achieve success, eyecare practitioners must be even more diligent about treating dry eye and other sources of contact lens discomfort when fitting the presbyopic patient population with multifocal lenses.
Myth #9: Multifocal contact lens wearers must wear their lenses full-time to be considered successful.
Fiction The MCO-VRI multifocal lens study found that wear time varied for successful multifocal lens wearers. Soft lens patients wore their lenses anywhere from 3.5 to seven days a week for seven to 13 hours/day. GP lens wearers tended to wear their lenses longer, for five to seven days/week and 10 to 18 hours/day (Dinardo et al, 2014). Some patients simply do not want to wear their lenses full-time, but still consider themselves successful, happy multifocal lens wearers. It was not uncommon to find patients who reverted to glasses during the week for certain activities.
Even if patients do not want to wear lenses 100% of the time, it does not mean that they are not a candidate for multifocal contact lenses. A daily disposable multifocal lens may be perfect for such patients. Conversely, many satisfied multifocal contact lens wearers can and do wear their contact lenses almost exclusively. For these patients, choose a multifocal lens design with great distance, intermediate, and near ranges to optimize success for all daily activities. According to Bennett and Quinn (2014), hybrid or scleral lens multifocal designs might be ideal options, followed by aspheric GP lenses or segmented trifocal GP lenses.
Myth #10: Multifocal lenses are not worth the hassle for either eyecare practitioners or patients.
Fiction Multifocal lenses are beneficial to both patients and practitioners. By adding them to the portfolio of lenses offered to patients, practitioners can fulfill a large unmet need, not to mention enjoy increased referrals due to increased patient satisfaction.
Research confirms that multifocal lenses do indeed improve the quality of life in presbyopic patients. Richdale et al (2006) examined qualify of life in multifocal lens wearers using the National Eye Institute Refractive Error Quality of Life Instrument (NEI-RQL-42). This survey is intended to assess quality of life as it relates to refractive error correction (Berry et al, 2003). It found that although patients sometimes report suboptimal visual performance and/or discomfort with multifocal lenses, it does not seem to negatively affect patients’ level of happiness and satisfaction. The most significant improvement in quality of life was related to satisfaction with physical appearance while wearing contact lenses compared to their habitual correction. More recently, a pilot study at MCO confirmed the study by Richdale et al (2006) and also found a statistically significant increase in overall satisfaction with correction among multifocal lens wearers (Hall et al, 2014). Using a contact lens-specific quality-of-life survey (Pesudovs et al, 2006), the MCO-VRI multifocal lens success study discovered not only improved quality of life among multifocal lens wearers in terms of physical appearance, but also an increase in general happiness and the ability to perform desired activities of daily living (Dinardo et al, 2014).
Success in multifocal contact lenses has been defined in many ways. Various measures for success have included wear time, visual performance, and patients’ willingness to acquire more lenses. However, success is subjective to some degree. Quite possibly, practitioners have higher expectations for success than their patients do. Combined with a variety of misconceptions, this may lead practitioners to be apprehensive about fitting multifocal lenses. Ultimately, myself and other researchers at MCO came to the conclusion that when measuring patient success with multifocal lenses, the best ruler is the patients themselves. CLS
Acknowledgements: Craig Norman, FCSLA; Bruce Morgan, OD, FAAO; Chad Rosen, OD, FAAO; Joshua Lotoczky OD, FAAO; Andrea Sewell OD; Stephanie Ramdass, OD.
For references, please visit www.clspectrum.com/references and click on document #228.
Dr. Dinardo is an associate professor at the Michigan College of Optometry. She is a clinical preceptor in contact lens and primary care clinics. Her research interests include contact lenses for presbyopia, corneal reshaping, custom soft contact lenses, scleral lenses, and contact lens care systems. You can contact her at firstname.lastname@example.org.
Trevor Fosso is an optometry student at Michigan College of Optometry and is a student research fellow with the Vision Research Institute.