Presbyopia presents one of the most significant challenges in contact lens practice. With each passing year, more of our contact lens patients become presbyopes. As a result, many patients need lenses either for near vision correction or both for near and distance vision correction (in cases of clinically significant hyperopia). These factors create an increased demand for contact lens alternatives for presbyopia management. Fortunately for the practitioner, the armamentarium of lens designs available to meet this demand is expanding, as are the success rates found with contemporary presbyopic contact lens designs.
Monovision contact lens correction remains the mainstay of contact lens-based presbyopia management. However, as the amount and success rates of multifocal contact lenses continue to increase, we can provide optically superior alternatives for our patients and allow them to remain functionally binocular. Fortunately, todays multifocal contact lens technologies allow us to achieve this goal much more often for our patients.
This article will review many of the most current multifocal contact lens options available today, with emphasis on the largest growing segment of multifocals: disposable soft multifocal lenses. But, to be successful, contact lens practitioners should realize that incorporating customized soft multifocals, gas-permeable multifocals and even hybrid multifocals will significantly increase the practices ability to meet the needs of presbyopic patients interested in contact lens wear.
Key Issues to Discuss with Prospective Presbyopic Contact Lens Wearers: Individual vision requirements and visual demands, such as environmental and lighting conditions, as well as gaze directions during various vision tasks. Current vision correction modalities. Is the patient satisfied? What limitations does he or she have? Current ocular health status. How might the patients ocular health, especially as it relates to potential ocular surface disease, allergy or dry eye, affect his or her ability to wear presbyopic contact lenses? The various presbyopic contact lens alternatives available. Remember to discuss the advantages and limitations of each lens. The philosophy of under-promise and over-deliver may come in handydont over-sell the product, only to have the patient come back with complaints. The patients goals in terms of contact lens wear. What does the patient want? Does the patient want or need full-time wear with no use of additional spectacle lenses, or is he or she willing to accept the use of part time over-spectacle correction if needed for limited specific tasks? What about part time contact lens wear for limited activities? The key in patient consultation for presbyopic contact lens wear is setting realistic expectations. A Few Cases in Point A 46-year-old man, a regional sales representative who does a great amount of driving to accounts, as well as extensive near work on a laptop computer, is currently wearing distance vision glasses and removing them often for near activities. He has worn single-use disposable contact lenses in the past for sports activities. His manifest refraction is -1.25D-0.25x15 O.D. and -1.50DS with a +1.00D add O.S. He has no ocular or systemic health issues. -4.00D-1.50x170 O.D. and -3.50D-1.50x05 O.S. with a +2.25D add O.U. Biomicroscopy reveals bilateral dry eye findings, including staining patterns at 3 oclock and 9 oclock.
Balanced Progressive Technology
In this case, there are multiple contact lens options available. The key to success here, however, is to not compromise the patients distance vision while providing adequate near function. Binocularity is also key, due to his extensive driving activities. Disposable multifocal lenses could be a great first choice. Designs that would work include center-distance, low-add progressive lenses, which will emphasize distance vision and should provide enough add power to meet the patients needs. Other options are a low-add anterior aspheric lens or a low-add multi-zone lens.
A 58-year-old woman has been wearing monovision gas-permeable lenses for the past eight years with limited success. She spends many hours in an office at a computer; she views her 21-inch screen at a distance of about 30 inches. Her problems with her current gas-permeable monovision correction include a lack of overall clarity at either distance or near, eye strain during daily activities and a degree of physical discomfort with the lenses. Her manifest refraction is
The main issues to address in this case include improving binocular function over monovision, addressing the patients astigmatism (which is primarily corneal in nature), meeting the higher near add requirement, providing a good near range of vision to allow for clear function at the computer, and addressing the comfort and dry eye problems she is currently experiencing. One option would be to fit her with another multifocal gas-permeable lens that would hopefully be more comfortable. In this instance, consider such design modalities as aspheric multifocal gas-permeable lenses (most likely combination anterior and posterior aspheric lenses, or other combination multifocal gas-permeable designs, due to the patients add requirement), or a concentric progressive multifocal gas-permeable lens (center distance, progressive intermediate, and near surround). Other options might include the use of a hybrid multifocal with a lower add power (+1.75D or maybe even +1.25D), since clinical experience with this design has shown that it provides a higher effective add than predicted by the labeled add power, and as such, lower add lenses may provide a larger near vision range to accommodate this patients computer needs. Toric soft multifocal lenses could also be considered; however, with add requirements above +1.75D, a modified monovision fit is often required. Finally, consider a piggyback fit with a gas-permeable multifocal lens over a high oxygen-transmission silicone hydrogel lens for improved comfort.
A 51-year-old woman has noticed symptoms of progressive blur at near and progressive increased dependence on her reading glasses. She plays tennis, and she is very involved in numerous charity organizations; she attends and plans their meetings and social functions. This patient is quite disturbed about having to use reading glasses. She demonstrates no distance vision symptoms, and there is no ocular or medical reason not to consider contact lenses. Her manifest refraction is +0.25DS O.D. and -0.25D -0.25x65 O.S., with a +1.50D add O.U.
This case is more challenging than it may seem at first; the patients distance vision without correction is excellent. Virtually any contact lens placed on the eyes will help her near vision while compromising her distance vision. So, there are two main points here. First, we should not fit her dominant eye, her right eye, with any contact lens. In this way, we will try to maintain clear distance vision. Second: Advise the patient that her vision with contact lens correction will not be as clear at distance as it is with no correction, nor at near as it is with her reading glasses. So, we will fit only the non-dominant eye with a contact lens. Perhaps the first choice in such a case would be a simple near lens for true monovisionhowever, the patients intermediate vision may not be acceptable, and the binocular vision asymmetry may be greater than the patient will want to tolerate. Or, a disposable multifocal contact lens might fit the bill for part-time wear. We can utilize any of the available disposable multifocal soft lenses for part-time or more frequent wear. Remember to provide maximum near vision performance, so she will not feel the need to use any glasses over the lens for near activities.
CooperVision coined the term Balanced Progressive Technology to describe the system used in its Frequency and Proclear Multifocal lenses. This system allows practitioners to manage every phase of presbyopiafrom emerging stages through advanced stages. Both lenses use the D lens and N lens design system. The D lens has a central zone of distance correction (2.3mm in diameter) surrounded by an aspheric zone of progressive near power (out to 5mm in diameter) that provides intermediate vision correction. A pure near power zone (out to 8.5mm in diameter) is located at the periphery of the lens. The complementary N lens has a central zone of near correction (1.7mm in diameter) surrounded by an aspheric zone of progressive distance power (out to 5mm in diameter) with a pure distance power zone (out to 8.5mm in diameter) around the periphery.
Although the D lens will typically emphasize distance vision and the N lens will emphasize near vision, in cases of mild presbyopia, the D lens often provides clear distance, intermediate and near vision. As such, it can be used in both eyes if found beneficial. As the presbyopia progresses, however, the D lens will be fit in the dominant eye and the N lens will be fit in the non-dominant eye. This format provides clear distance, intermediate and near vision binocularly, though there will be some degree of monocular visual asymmetry (but far less from what is found in typical monovision).
The Frequency 55 multifocal is fabricated from methafilcon (55% water content), and the Proclear multifocal is made from omafilcon (62% water content). Many practitioners have found the omafilcon to perform better for dry eye patients and for patients who tend to manifest contact lens deposits more frequently.1 The Proclear lens is available in both the XR (extended range) and Proclear Toric versions.
The Biomedics EP lens is another option from CooperVision. A modified version of the multifocal D lens for emerging presbyopes, its central zone is slightly larger and has a slightly less effective add power than the lowest add power available with the D multifocal lens. As such, it provides adequate near power while emphasizing sharp distance vision.
Some practitioners have also used the EP in a modified monovision format where the lens used for the dominant eye is prescribed for maximum distance vision and the lens used for the non-dominant eye is prescribed for optimal near vision. In comparison to traditional monovision, this modality allows for improved intermediate vision and some degree of improved binocularity. Practitioners have successfully used this format in refitting current monovision patients in order to provide an upgrade in visual performance.
Aspheric Multifocal Designs
Bausch & Lomb provides two lens material options for its aspheric disposable multifocal contact lenses. The SofLens MultiFocal is fabricated from polymacon (38% water content). The PureVision MultiFocal is fabricated from balafilcon (36% water content), a highly oxygen-permeable silicone hydrogel material. Both lenses utilize anterior surface design aspheric technology. They are each available in a low add and high add versionthe aspheric power array on the front surface of the lens generates less or more near power, respectively.
Patients who require moderate to higher add powers often will be fit with one low add lens for the dominant eye and one high add lens for the non-dominant eye. This creates a form of modified monovison, resulting in better intermediate vision and improved binocular function. Patients requiring lower add powers (typically under +1.50D) often will function quite well at all viewing distances when fit with two low add lenses. Patients who need high add powers (+2.00D or more) will typically require the high add lens fit on the non-dominant eye (and the low add lens fit on the dominant eye) to be prescribed with more relative plus power than the distance vertexed refraction to achieve proper near vision.
More advanced presbyopic patients may also achieve good distance and near vision when fit with high add lenses O.U. If you are able to achieve clear distance and near vision with an aspheric contact lens, you will also achieve good intermediate vision.
The SofLens MultiFocal is available in two base curves (8.5mm and 8.8mm) and one diameter (14.5mm). The distance power range is from +6.00D to -10.00D in 0.25D steps, along with the two add powers (low and high). The PureVision MultiFocal is available in one base curve (8.6mm), one diameter (14mm) and the same power range and add powers as the SofLens MultiFocal.
Unilens laboratories also offer anterior surface aspheric multifocal disposable and frequent replacement contact lenses. The EMA Multifocal disposable lens also is an anterior surface aspheric lens with maximum near power in the center. It is fabricated in polymacon (38% water content) and is available in a low and high add version. Available parameters include two base curves (8.5mm and 8.8mm) with one diameter (14.5mm), and a power range of -10.00D to +6.00D in 0.25D steps. The EMA Multifocal is a lathe cut design based on the C-Vue disposable multifocal near-center profile. The C-Vue 55 Multifocal and C-Vue 55 Toric Multifocal are based on the C-Vue design, but are fabricated from methafilcon (55% water content).
CIBA Vision produces two front-surface aspheric disposable multifocal contact lens designs. The Focus Monthly progressive lens utilizes a unique power array on the front surface of the lens, where the greatest near power is concentrated in a relatively small central area and surrounded by a quickly progressive increase in relative distance power. The lens is fabricated from vifilcon (55% water content). The lens is available in two base curves (8.5mm and 8.9mm) and one diameter (14mm). The power availabilities range from +6.00D to -7.00D in 0.25D steps. The effective add is claimed to be up to +3.00D; however, in order to achieve higher add requirements, the lens must be fit with relatively greater plus power and tends to blur distance vision. In these cases, as with other lens designs, the Focus Monthly progressive lens often must be fit in a format similar to modified monovision.
The Focus Dailies Progressive single use lens is also available. This daily disposable lens is based on the same design as the Focus Monthly progressive lens and is fabricated from nelfilcon (69% water content). Parameters include one base curve (8.6mm) and diameter (13.8mm), with spherical powers ranging from -6.00D to +5.00D.
CIBA Vision will soon introduce a new disposable multifocal, the Air Optix Aqua Multifocal. The lens will be fabricated from lotrafilcon B, and it will incorporate three unique add powers in order to accommodate all stages of presbyopia. This lens is expected to be introduced during the first part of 2009.
Multi-Zone Multifocals
Vistakons Acuvue Bifocal lens utilizes the concept of multi-zone technology to provide vision correction for presbyopes. Made of etafilcon, this lens has a 58% water content and features a 2mm central distance zone surrounded by alternating zones of near and distance power. In total, there are three distance zonescentral, intermediate and peripheralalternating with two zones of near power. The multifocal optics are located on the posterior surface of the lens. The total optical zone is 8mm in diameter. The available parameters for the Acuvue Bifocal are a base curve of 8.5mm, diameter of 14.2mm, sphere powers ranging from -9.00D to +6.00D in 0.25D steps, and add powers of +1.00D to +2.50D in 0.50D steps.
Clinical experience with this lens has shown that when required add powers are over +2.00D, the lens will compromise distance vision. This may be countered with a modified power approachuse a lower add lens in the dominant eye and a higher add lens in the non-dominant eye. Some patients have reported a 3-D effect, where print seems to rise off of the page when viewing at near. This phenomenon often becomes less noticeable over time, but can persist for some cases.
Vistakon will be introducing its Oasys for Presbyopia multifocal in 2009. The company reports that the lens will be fabricated from their Oasys silicone hydrogel material (senofilcon A, 38% water content) and will address the needs of early, moderate, and advanced presbyopia via its new multi-zone multifocal design. The lens is currently undergoing pre-market clinical trials.
Customized Soft Multifocals
Patients often present with vision or fitting demands that require the use of customized multifocal lenses that are only available for annual, semi-annual, or possibly quarterly replacement due to the expense of manufacturing them.
These conventional replacement soft multifocal lenses are available in a variety of designs, including aspheric center near, aspheric center distance, concentric and translating. Toric multifocal lenses are also available for customized conventional replacement. These lenses allow the contact lens practitioner to more precisely fit patients, due to the far greater array of parameters available.
Hybrid Multifocal Contact Lenses
The SynergEyes Multifocal is a hybrid lens. The central gas-permeable section provides multifocal optics and is fabricated from Paragon HDS 100 material (100 Dk/t). The soft periphery is made from a polyHEMA material (27% water content). The lens utilizes a center near concentric design, with a narrow aspheric transition zone between the near and distance sections. Parameters include one diameter (14.5mm), base curves ranging from 7.1mm to 8.2mm in 0.1mm steps, a soft skirt curve 1.0mm or 1.3mm flatter than the base curve, central near zone diameters of 1.9mm or 2.2mm, spherical distance powers from -9.00D to +4.00D, and add powers from +1.25D to +2.25D in 0.50D steps. The lens typically is fit about 1.5mm steeper than the flat K, or close to mid-K for higher toric corneas, and the required distance power must be adjusted accordingly. The lens must be fit with definitive central clearance in the gas permeable area so it can move appropriately. The hybrid multifocal design allows for the superior optics of a gas-permeable center and the improved centration characteristics of the soft skirt (which is critical to the success of a concentric multifocal contact lens).
SynergEyes is currently developing a new silicone hydrogel material skirt and peripheral skirt curve design for all of their hybrid lenses. The multifocal design will ultimately be available with this new skirt technology in the relatively near future.
Gas-Permeable Multifocal Lenses
Gas-permeable lenses are known for their superior optics in the correction of presbyopia. Virtually every possible multifocal design is available in a gas-permeable lens. The use of aspheric front, aspheric back, concentric, translating or alternating designs and numerous combinations of all of these allow gas-permeable lenses to meet the visual needs of most presbyopes.
The limiting factor for the success of gas-permeable multifocal lenses has always been adaptation to the physical sensation of the lenses on the eyes. Typically, the majority of patients fit in gas-permeable lenses will become used to the lenses within one or two weeks. Novel adaptation approaches, such as the use of topical anesthetics at dispensing, the use of NSAIDs drops during the first few days of lens wear and the modification of materials and fitting techniques, may significantly improve the success rate of comfort adaptation with gas-permeable lenses. Contact lens practitioners should consider the benefits of gas-permeable multifocal lenses when considering options for their presbyopic patients.
With the vast array of multifocal contact lenses available to todays practitioners, the first option for contact lens correction of presbyopia should shift from conventional monovision and reading glasses over distance-vision contacts to the use of multifocal lenses.
We are now able to fit more patients with multifocal contacts and allow them to maintain clear distance, intermediate and near binocular vision with excellent physical comfort and optimal physiological response. If you have not yet embraced the fitting of multifocal contact lenses, now is the time to do so.
Dr. Eiden is president of North Suburban Vision Consultants, Ltd., in Deerfield and
1. Lemp MA, Caffery B, Lebow K, et al. Omafilcon A (Proclear) soft contact lenses in a dry eye population. CLAO J 1999 Jan;25(1):40-7.
