In my relatively short career as a practicing optometrist, there have been a number of new soft contact lens designs emerging with advancements in comfort and visual outcomes.
I’ve come to notice when a company comes out with a novel lens, the first designs released tend to be a spherical or multifocal design.
As a hyperope with moderate astigmatism and no fading accommodation (yet), I may feel a little left out in getting to try these out myself, but it’s easy to see why multifocals are such a priority for these manufacturers.
Prevalence of presbyopia
It has been reported that roughly a quarter of the world’s population is presbyopic, and in 2020, 123 million people in the United States were presbyopic.1
As baby boomers continue to age and Gen-X and millennials grow towards this group, it’s likely we’ll see this proportion increase.
A natural facet of aging, presbyopia typically occurs around someone’s mid-40s and progressively makes it more difficult for them to focus on near objects.
Considering contacts for today’s presbyope
It’s no mystery that digital devices are very prevalent in today’s workplaces and our daily lives. Having multiple monitors or working simultaneously from different devices is commonplace. With this shift in visual demands, the demand for functional vision at various distances has greatly increased.
The use of contact lenses or spectacle correction has largely varied with preference and lifestyle. However, the COVID-19 pandemic played a large role in soft contact lens wear habits that continue to echo today.2
The pandemic resulted in a significant rise in individuals working from home as well as increased screen time. Because of this, some patients began to demonstrate presbyopic symptoms that were previously unaffected. Likewise, some patients being bothered by fogging issues with their masks and glasses turned to contact lenses for relief.
Laser vision correction and dry eye in presbyopia patients
It’s also been estimated that in the last 15 years, roughly 600,000 laser vision correction procedures have been performed each year (though variations exist).3 This group of people has demonstrated motivation to be spectacle-free and are likely to maintain this attitude as they become presbyopic, making them great candidates for multifocal contact lenses.
The 40-plus-year-old community also harkens to the Tear Film and Ocular Surface Society Dry Eye Workshop (TFOS DEWS) II study where, depending on definition, dry eye syndrome was found to be as prevalent as 50% in certain populations.4
Since this is also the group we’re discussing in reference to presbyopic correction, it’s important to bear in mind this association with dryness complaints to help ensure our patients' success with contact lenses.
Figure 1 outlines considerations for optometrists when deciding whether monovision, distance contacts and readers, or multifocal contacts are the best fit for their patients.
Figure 1: Courtesy of Thomas Stokkermans, OD, MS, PhD.
Approaches for correcting presbyopia with contact lenses
Figure 2 highlights various approaches for correcting presbyopia with contact lenses (CLs).
Figure 2: Courtesy of Myopia Profile.
Monovision contact lens correction
Monovision correction involves separating the focal points of the eyes to provide functional vision at a couple of set distances ideally. This method dates back to roughly the 1960s and existed prior to the creation of multifocal optics, which occurred later in the 1980s.5,6
Typically, the patient’s dominant eye is calibrated for distance correction, and the opposite eye is dialed in for near tasks such as their computer or reading. In this scenario, we are working with a patient’s brain as much as their eyes.
Their visual system must adapt to know which eye should be used for each task they are performing. Ideally, this change should occur easily during wear to make this process as fluid as possible with little interference between the eyes.
Optimal patient profiles for monovision CL correction
Monovision can be a good option if the patient has a higher amount of astigmatism that cannot be corrected in commercially available multifocal lenses. That being said, those patients may be excellent candidates for more custom or specialty contact lens designs.
For other patients, their monovision setup may have been created for them some time ago, and they may be hesitant to restart the process of correcting their presbyopia in another design.
Reminding us of the numbers stated earlier for laser vision correction performed over the years, some surgeons may opt to incorporate a little monovision into their post-operative refractive outcomes.
The hope here would be to allow patients to have more time before becoming symptomatic of near issues. In these cases, simply increasing the amount of monovision correction can be a simple way to keep the same setup, just with more add power.
Limitations of monovision contact lens correction
The main drawbacks of monovision correction include the fact that it allows for less flexibility and fluidity in working distances as well as the loss of stereopsis.
Studies have demonstrated that multifocal soft contact lenses have improved intermediate acuities after adaptation compared to monovision correction. Monovision, on the other hand, tends to show better distance and near acuities, but lacks this correction for intermediate tasks.7
Options for monovision CL correction of presbyopia:
- Any sphere or toric lens can be utilized to create a monovision setup.
Multifocal contact lens presbyopia correction
Simultaneous-vision multifocal contact lenses have variations between brands and can incorporate proprietary designs, but simply put, they work by having a distance correction in one zone of the lens and the patient’s “add” in another zone.
This may occur in a concentric-ring pattern, aspheric powers, or a number of other options, including near or distance-centered designs. The patient then moves between these zones naturally as their pupil changes size in regards to their working distance.
Some manufacturers keep these zones the same size for all add powers, while others account for age-related changes to pupil sizes to better match the patient’s physiological state. Likewise, brands may offer two add powers, three add powers, or a multitude at different intervals similar to the add power in their spectacle prescription.
Using fitting guides to maximize the benefits of multifocal CLs
These differences in approaches to multifocal correction may take some experimenting to learn which ones work best for each individual patient and their visual system.
When it comes to fitting these lenses, it is usually recommended to reference the manufacturer’s fitting guide initially. These guides have been validated to recommend the best initial diagnostic lens and can lead to the most efficient and successful prescription.
The multifocal design maintains the retention of stereopsis and can allow for improved visual function at varied focal lengths. Depending on which zone of the lens they fall in, they can have functional distance, intermediate, and near vision as opposed to two set distances with monovision correction. This advantage cannot be stressed enough as we’ve discussed the various demands of our intermediate and near vision in today’s digital world.
Limitations of multifocal contact lens correction
The disadvantages of the multifocal zones begin to emerge when lighting conditions are inadequate or due to pupil complications.8 If a pupil is larger or smaller than expected for a given task, the patient may not see through the proper zone in the lens.
Pupils may also be abnormally displaced within the iris or have an irregular shape due to previous trauma. These eyes can run into issues with multifocal optics, and their approach may need to be edited.
Figure 3 shows trends in pupil size change by age and refraction.
Figure 3: Courtesy of Johnson & Johnson Vision.
Options for multifocal CL presbyopia correction:
- Air Optix Multifocal
- Dailies AquaComfort Multifocal
- Dailies Total One Multifocal
- Biofinity Multifocal (also available with astigmatism correction)
- Proclear Multifocal
- Clariti One Day Multifocal
- MyDay Multifocal
- Ultra Multifocal (also available with astigmatism correction)
- BioTrue Multifocal
- Infuse Multifocal
- Acuvue Oasys Multifocal
- Acuvue 1-Day Moist Multifocal
- Acuvue 1-Day Oasys MAX Multifocal
Extended depth-of-focus (EDOF) contact lenses
EDOF lenses have emerged as one of the newer players in the game of presbyopic-correcting contact lens options. As such, there are fewer lens choices in this category compared to other designs, but their impact is already making waves.
Extended depth-of-focus lenses work to further improve the wearer’s viewing range by incorporating more varied focal length-correcting areas of the lens. This allows the lens to perform better for intermediate and near tasks while preserving a high-quality distance view.
Some reports have also demonstrated these lenses have fewer issues with pupil size and location as well as provide less susceptibility to inherent optical aberrations.9
Limitations of EDOF contact lenses
As the EDOF lens style is still relatively new, there is still a lot we are learning about their designs and which cases may really benefit from their incorporation. While this technology continues to evolve, I would expect to see advances in designs that favor fluidity and customization for near-vision tasks.
Figure 4 illustrates the differences in foci between single vision, center-near multifocal, and EDOF contact lenses.
Figure 4: Courtesy of Daniel Fuller, OD.
Options for EDOF CL presbyopia correction:
- NaturalVue Multifocal
- SynergEyes iD EDOF
Conclusion
As we’ve discussed, devices are very present in our daily lives, and ocular surface disease is very prevalent in our patient base. There are a number of considerations when fitting a patient with contact lenses, but at the end of the day, if their vision doesn’t allow them to function well, they likely won’t continue with lens wear.
Understanding the various multifocal options available and correctly utilizing them is a top priority so that we can continue to provide our patients with the best glasses-free vision they can have.
