Presbyopia is an ocular condition described as a gradual loss of accommodation or inability to focus at near. In 2015, it was estimated that 1.8 billion people suffered from presbyopia worldwide.¹

Of those, 826 million experienced some form of visual impairment due to inadequate or lack of access to appropriate eye care to correct presbyopia.¹ Although presbyopia tends to be more prevalent in regions of the world where people have longer life spans, people living in regions that have fewer resources experience more visual impairment from uncorrected presbyopia.¹

In a 2021 study that explored patients’ attitudes toward and beliefs about presbyopia, approximately 65% of those surveyed were not even familiar with the term “presbyopia,” nor did they have a good understanding of what presbyopia means.² The majority of participants surveyed believed presbyopia is associated with age and that it is a condition that everyone will experience.

Surprisingly, 71% of questionnaire participants exhibited a negative stance toward bifocal or multifocal contact lenses, which may be the result of participants wearing multifocal contact lenses previously and experiencing poor visual quality or never having heard of multifocal contact lenses before.² This suggests that eyecare practitioners may not be educating all presbyopic patients about contact lens options to correct presbyopia, as evidenced by another survey that reported that more than half (55%) of eyecare practitioners only occasionally discussed contact lens options for presbyopes.³

Morgan and colleagues conducted a survey that analyzed contact lens-prescribing habits in 38 countries over a five-year period (2005 to 2009).⁴ Out of the 16,680 presbyopes fit with contact lenses, only 37% were fit with either multifocal (29%) or monovision (8%) contact lenses. The remainder were fit with single vision distance contact lenses and utilized reading spectacles for near tasks.

The authors postulated that a lack of knowledge or skill in those fitting multifocal and monovision contact lenses, the potential for presbyopic contact lenses to provide inadequate vision and comfort, or the nonexistence of a “perfect” multifocal contact lens were among the reasons why fewer than half of presbyopes were fit with monovision or multifocal contact lenses.⁴

Contact Lens Spectrum annually publishes contact lens-prescribing habits among international eyecare practitioners. The percentage of soft multifocal contact lenses fit has been trending upward while the number of soft monovision contact lenses fit have been trending downward. Most recently, in 2021, multifocals comprised 49% of all presbyopic fits, while monovision encompassed 11% of all presbyopic fits.⁵ While GP prescribing habits followed a similar pattern in terms of the distribution between multifocal and monovision designs, only 7% of patients fit with GP lenses were prescribed a multifocal design and 3% were given a monovision design.⁵

A recent survey of 125 eyecare practitioners in the United States revealed that the trend has been moving toward an increase in fitting multifocal contact lenses and a decrease in fitting single vision distance contact lenses paired with readers or monovision contact lenses.⁶

Although the number of soft and GP multifocal contact lenses fit is increasing, the surveys and questionnaires discussed above suggest that there is room for more patient education about the definition of presbyopia and the available contact lens treatment options. As more patients become presbyopic, eyecare practitioners are in the best position to educate patients about presbyopia, expectations, treatment options, and a patient’s ideal treatment.

Treatment options for presbyopia are numerous and growing and can be categorized into optical (spectacle and contact lens), surgical (presbyopic-correcting corneal surgery and intraocular lenses), and pharmaceutical. While advancements have been made in the spectacle, surgical, and pharmaceutical treatment arenas, the discussion of these advancements is beyond the scope of this article.

The remainder of this article will review the following contact lens designs, as well as their advantages and disadvantages and the recent technological advancements in each category:

1. Single vision distance contact lenses with reading spectacles
2. Monovision contact lenses
3. Bifocal/multifocal contact lenses

OPTION 1: SINGLE VISION LENSES

Single Vision Distance Contact Lenses with Reading Spectacles Fitting presbyopes with single vision distance soft or GP contact lenses and prescribing a reading prescription to wear for near tasks is most simplistic. In this modality, the patient is fit with soft or GP lenses that optimize distance visual acuity in each eye, and a single vision or bifocal/multifocal reading prescription is prescribed to wear over the contact lenses. The patient experiences the same clear distance vision that they were accustomed to previously and has clear vision at intermediate/near with the use of spectacles.

There is a wide array of soft and GP brands/designs, materials, replacement schedules, and spherical and astigmatic optical parameters available. However, patients may become frustrated with the frequent application and removal of the reading glasses depending on their intended visual target.

OPTION 2: MONOVISION

Monovision Contact Lenses Monovision was a reasonable optical treatment option to correct presbyopic patients with contact lenses before the rise of multifocal contact lenses. Monovision has been perceived as easier and less costly to fit compared to multifocal contact lenses. The patient’s dominant eye is corrected fully for distance, while the nondominant eye is corrected optimally for either near or intermediate viewing. A patient can continue with the same contact lens brand, design, and material that they were successfully wearing prior to becoming presbyopic.

One disadvantage of monovision is that patients may experience a decrease in or loss of stereopsis, up to 150 seconds of arc, which often increases as their add power increases.^7-9 In addition, contrast sensitivity can be compromised with monovision.^10,11 As the vast majority of real-world objects are low contrast, it is important to assess and measure both low-contrast and high-contrast visual acuity during the contact lens examination. Patients wearing monovision contact lenses should also be educated about potential problems with nighttime driving, including glare.¹²

OPTION 3: MULTIFOCAL LENSES

Soft Contact Lenses Soft multifocal contact lenses have experienced the largest growth. Currently, there are dozens of soft multifocal contact lenses available in both non-custom and custom designs.¹³ Although multifocals are one of the fastest-growing contact lens presbyopic categories, a hesitancy to fit them still remains.

Eyecare practitioners may assume that patients do not want to pay for the added expense of a multifocal, they may not be up to date on all the new multifocal lens design options, or they may not want to absorb the additional chair time needed for the fitting and subsequent follow-up care. Educational resources regarding new multifocal designs are numerous, and after completing a few multifocal fits, practitioners will gain additional experience and confidence to start offering multifocal contact lenses to all patients.

The majority of currently available soft multifocals use the principle of simultaneous vision, which presents multiple powers within the pupil at the same time. In other words, light rays from both distance and near targets are focused on the retina simultaneously.^15,16 When viewing distance targets, patients selectively suppress the near blurred images; blurred distance images are suppressed when viewing near targets. The three simultaneous contact lens designs available include aspheric, concentric/annular, and diffractive. Multifocal lenses may also contain a combination of aspheric and concentric design features.

Aspheric lenses exhibit a gradual change in curvature on either the anterior or posterior surface.¹⁴ This change in curvature creates an increase in plus power toward the periphery (center-distance), or the asphericity may create more plus power in the center of the lens as well (center-near). Concentric or annular designs utilize concentric zones of distance and near powers and are also available in both center-distance and center-near designs.

The majority of currently manufactured soft multifocal contact lenses are center-near in design and are available in monthly, biweekly, and daily disposable replacement modalities.¹⁵ Recent technological advancements have led to the introduction of several new center-near and center-distance toric multifocal designs, which have been beneficial for presbyopes who have significant levels of astigmatism.¹⁶

Custom Soft Lenses Today, custom soft contact lenses are more accurate and reproducible. These lathe-manufactured lenses are available in a wide range of base curve radii, diameters, powers, multifocal designs (center-distance/center-near), and multifocal zone sizes. Previously, custom soft lenses were only manufactured in lower-Dk hydrogel materials, but now the majority of presbyopic multifocal designs are available in a higher-Dk silicone hydrogel material.

Custom soft multifocals are ideal for patients who have not have success with previous multifocal designs. Whether the lenses fit poorly on the cornea or the patient has a unique prescription outside of standard multifocal lens parameters, custom soft multifocal lenses have the ability to provide improved patient satisfaction. It is ideal to keep patients who are habitual soft contact lens wearers in a soft contact lens, and custom soft contact lens multifocals give eyecare practitioners another tool in their toolbox that may offer better comfort and enhanced visual acuity.

Although custom lenses may center better, decentration may still occur for some patients. Multifocal optics that decenter can cause a degradation in the retinal image quality. Some custom soft multifocal designs offer decentered optics that align the center of the multifocal optic zone to the patient’s visual axis. Corneal topography may be useful when assessing how a multifocal contact lens centers on the eye in relation to the pupillary axis.

To create better alignment, the multifocal optic zone may need to be decentered nasally 0.5mm to 1.0mm.¹⁷ One study reported that 19 out of 20 subjects preferred multifocals that have a 1.0mm nasal offset compared to multifocal lenses that have no offset, reporting that they significantly improve subjective visual performance when viewing near targets.¹⁸

Modified Monovision On occasion, patients may benefit from a combination of lenses to enhance either distance or near vision. When a patient is fit with a single vision distance lens on the dominant eye and a multifocal on the nondominant eye, this is referred to as modified monovision.¹⁶ This scenario is ideal for individuals with greater distance tasks and fewer near tasks.

Hybrid Multifocal Lenses The newest generation of hybrid multifocal lens designs was recently introduced. Optically, the new hybrid multifocal incorporates an extended depth-of-focus (EDOF) design and utilizes higher-order aberrations to provide patients with a longer depth of focus.¹⁹ This results in clearer vision at distance, intermediate, and near. Additional advancements in hybrid technology have produced a soft skirt and GP lens center that have higher Dk values than previous hybrid designs. Furthermore, a new linear skirt allows for more customization of the periphery.

Hybrid lenses are ideal for patients who desire the crisp visual acuity that is often achieved with GP lenses while maintaining the comfort provided by a traditional soft contact lens. Hybrid multifocals are ordered empirically, which provides an additional “wow” factor to the patient when they look through the first lens that they apply compared to a diagnostic lens fit in office, which most likely will not be the exact prescription required.

GP Lenses GP bifocals and multifocals are traditionally known for their superior vision quality at distance and near. GP multifocal designs can be categorized into simultaneous vision (aspheric) and translating (alternating image) designs.

Aspheric Multifocals Like soft aspheric multifocals, aspheric GP multifocals have a gradual change in curvature along the anterior and/or posterior surfaces. Traditionally, aspheric GP lenses were fit significantly steeper than K, often 3D to 5D steeper. As a result, the lenses would sometimes cause corneal molding, which could lead to vision problems and discomfort.

Technological advances now allow an aspheric design on the anterior and/or posterior lens surface, which reduces the need to fit the lens significantly steeper than K.

The majority of low eccentricity lenses can now be fit approximately one diopter steeper than K to on-K.¹⁵ Modern aspheric multifocal designs are available in center-distance or center-near designs and can be fit empirically, which eliminates the need to perform an in-office diagnostic lens fitting and provides that “wow” factor to the patient when they experience the visual performance of the first multifocal fit.

Translating Bifocals/Multifocals Translating (alternating image) bifocals utilize the movement of the lower eyelid to cause the lens to translate superiorly during downgaze, which allows the patient to view through the near add power. With a properly fitting lens, excellent vision can often be achieved both at distance and near. GP bifocal segments are available in a variety of shapes and may also incorporate an annular or concentric design.¹⁶

Trifocal translating GP multifocal designs are also available, which provide improved vision at intermediate as well as near. Although translating GP lens designs may require additional chair time, they remain ideal for patients who prefer the sharpest vision possible at all distances.

Scleral Lens Multifocals Scleral lenses have recently undergone a boom in popularity. They are not only indicated for patients who have irregular corneas or ocular surface disease, they are also more commonly being fit for the correction of ametropia for regular corneas: myopia, hyperopia, astigmatism, and presbyopia. The number of scleral lens multifocal designs have increased over time, with almost every scleral lens manufacturer offering a multifocal design.

Optimal candidates for scleral lens multifocals include individuals who have regular or irregular corneas and are currently successfully wearing single vision distance scleral lenses.²⁰ Presbyopes who have regular corneas and who have not had success with soft multifocals or small-diameter GP multifocals may also be good candidates for scleral lens multifocals.

However, there are scenarios in which a multifocal would be contraindicated. If the patient is struggling to achieve optimal distance visual acuity with a single vision correction alone, it would be wise to avoid introducing a multifocal design, as there is potential to inadvertently change the patient’s distance visual quality due to the center-near correction commonly provided in these designs, especially for those who have moderate to severe keratoconus in which scarring is present.

The majority of scleral multifocal designs are simultaneous center-near designs, although a few center-distance and aspheric multifocal designs are available. Front-surface toric prescriptions may be necessary for patients who exhibit residual astigmatism. In the past, it was impossible to combine multifocal optics with a front-surface toric; however, advancements in technology now allow the two to coexist. As with scleral lens sphere and astigmatism powers, multifocal add powers are customizable, as are the distance/near multifocal zone sizes.

Scleral lenses tend to decenter inferior-temporally in the majority of patients. As a result, the patient is no longer looking through the geometric center of the optic zone, but rather slightly peripheral to the center. While vision may not be significantly affected with a single vision prescription, patients may experience the opposite when wearing scleral lenses that have multifocal optics that decenter.

To correct for the scleral lens decentration and align the patient’s pupillary axis with the optic zone center, scleral lens multifocals can be customized with decentered optics, a concept that has been utilized in the production of wavefront-guided scleral lenses for many years.²¹ Depending on the manufacturer, multifocal optics can be decentered in a stepwise fashion with preset horizontal and vertical decentration values, or they can be completely customized based on the fit of the scleral lens on the eye. Several diagnostic scleral lens designs incorporate laser etchings on the lenses that allow eyecare practitioners to measure the lateral and vertical decentration.

FUTURE CONTACT LENS OPTIONS FOR PRESBYOPIA

The increase in the number of new multifocal contact lens designs is expected to continue in the future. In addition to advancements and improvements in simultaneous soft lens multifocal optics and materials, several novel contact lens designs have been—or are currently being—developed and tested. Diffractive soft contact lens multifocals are created using laser-induced refractive index change (LIRIC). This process involves creating a diffractive structure on the front surfaces of hydrogel contact lenses that results in a +2.50D add power. The results have been promising thus far, as the diffractive multifocal lenses produced a significant visual benefit over the control multifocal lenses when viewing objects at near.²²

Accommodating contact lenses are lenses that transition focus between distance and near, either by applying a small electrical field across liquid crystals or using a mechanical control mechanism.²³ One such mechanism utilizes the pressure exerted from the eyelids to squeeze the contact lens and lift the surface,²⁴ while another utilizes pressure from the eyelids to redirect fluid within the matrix of the lens to the center of the lens. Both result in a change in optical power.²⁵ Finally, accommodating contact lenses could be controlled based on the patient’s gaze.²⁶

Suspended contact lenses that employ the upper eyelid to suspend the contact lens in place, which allows the eye to move freely upward and downward behind the lens, are currently in development.²⁷ As a result, the eye is able to view through the area of the lens specific to the patient’s visual demands (distance, intermediate, and near). Early trial results have been positive, and patients have experienced improvement in vision.²⁷

As with all aspects of eye care, it is important for eyecare practitioners to stay informed and up to date about future advancements in contact lens options for presbyopes and educate patients about new presbyopia-correcting technology.

The number of contact lens options for presbyopia have increased over time. Improvements in multifocal designs and lens materials, as well as expanded parameter availability and customization, have increased the number of presbyopic candidates for multifocal contact lenses. It is important that eyecare practitioners stay up to date on the latest presbyopia contact lens technology and multifocal designs, not only so they can educate their patients about presbyopia and available contact lens options, but also so they can be successful when fitting patients with these options to provide them with superior comfort and exceptional vision at distance, intermediate, and near. CLS

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