Issue: February 2019 2019

February 18, 2019

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Customize contact lens choice for patients with presbyopia and astigmatism

"At Issue" asked a panel of experts: For presbyopic contact lens patients with significant refractive astigmatism, what is your modality of choice?

Issue: February 2019 2019

Evaluate each patient individually

S. Barry Eiden, OD, FAAO, FSLS: Contact lens management of presbyopia is both rewarding and challenging at the same time. As with all contact lens cases we need to achieve the three key elements of success: optimized vision outcome, appropriate physiological response and comfortable wearing experience.

The bar is being set higher and higher in terms of expected performance as all forms of vision correction technologies improve. For most successful contact lens practitioners, each case is unique, and design selection decisions are made on a case-by-case basis.

Based purely on optical quality outcomes, in our experience, rigid corneal gas-permeable (GP) lenses have provided the best vision correction for our presbyopes with refractive astigmatism primarily induced by corneal toricity. The optical advantages of corneal rigid contact lenses include a fairly wide array of design options available (simultaneous aspheric, concentric and combination designs as well as translating/alternating designs), the ability to mask corneal toricity as well as the ability to account for residual astigmatism via anterior toric designs.

The greatest challenge however remains patient comfort. As such, refitting of existing corneal GP wearers into corneal GP multifocals seems to be a virtual slam dunk. Scleral GPs address the comfort issue tremendously and now are becoming more widely available in multifocal optics designs (although far more limited vs. corneal GPs). Cost to the patient for scleral multifocals also can be a challenge, as can the other scleral lens issues such as handling and mid-day debris accumulation in some cases.

Hybrid multifocals are an excellent option for those patients who have predominantly corneal toricity inducing the refractive astigmatism, as anterior toric designs are still not yet available in hybrids. The advantage of hybrids over corneal GPs include improvement in comfort and in centration of optics – which often is a challenge in simultaneous design corneal GPs. The disadvantage is that hybrids cannot address residual (internal) astigmatism and are available only in limited simultaneous designs. Soft toric multifocals have the advantage of comfort, availability in custom conventional and reusable disposable designs, as well as the ease of part-time use (which is attractive to many presbyopes). These designs have improved greatly over the past years, and parameters have been extended along with the ability to customize some (such as add powers, zone sizes and decentration of zones).

Monovision remains an option for all of these designs to address presbyopia and in our practice is a “fallback position” when multifocals do not work. Our philosophy always is to keep our patients as binocular as possible when addressing presbyopia.

For more information:
S. Barry Eiden, OD, FAAO, FSLS, is president and medical director, North Suburban Vision Consultants and Keratoconus Specialists of Illinois in Deerfield. He can be reached at: sbeiden@nsvc.com.

Disclosure:Eiden reports he is a consultant or has done research for Alcon, Allergan, Bausch + Lomb, CooperVision, Oculus, Oasis, Optovue, Shire, Special Eyes, SynergEyes, Visionary Optics and Vistakon. He has a financial interest in EyeVis Eye & Vision Research Institute and the International Keratoconus Academy of Eye Care Professionals.

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Consider patient wearing experience

Thomas G. Quinn, OD, MS, FAAO: The question is an important one, as we know 47.4% of the population has 0.75 D or more of astigmatism (Young et al.), which increases in frequency and degree as we age (Sanfilippo et al., Liu et al., Schuster et al.).

Multifocal or monovision? Studies have consistently found approximately seven out of every 10 subjects prefer multifocal correction over monovision (Johnson et al., Situ et al., Richdale et al.). This preference is born out of better performance with activities such as driving, computer use and television viewing (Woods et al.). So, multifocals will be my first option is most cases.

Is the astigmatism corneal? If vertexed refractive astigmatism does not match corneal astigmatism, I will generally recommend a toric soft multifocal. If the vertexed refractive astigmatism and corneal astigmatism match, I will lean toward a lens with a rigid optical system, as it will correct the astigmatism via the tear lens.

What is the patient accustomed to wearing? If the patient with matching refractive and corneal astigmatism has had prior success wearing corneal GPs or has very high visual demands, I will recommend a corneal GP multifocal. If the patient has worn toric soft lenses in the past, I will recommend a hybrid or scleral multifocal lens, as these will offer comfort similar to a soft lens, but generally with more consistent visual results than a soft toric multifocal.

If the patient is very focused on comfort and will simply be wearing the lenses for social occasions, I will recommend a soft toric option. If the patient tolerates plus power equal to the add power when held over one of their eyes while binocularly viewing a distant object through their best distance correction, I will go with monovision. Otherwise, I will prescribe a soft toric bifocal.

References:
Johnson T, et al. Multifocals vs. monovision: A comparative study. Presented at: Contact Lens Association of Ophthalmologists meeting; Las Vegas; February 2000.
Liu Y, et al. Invest Ophthalmol Vis Sci. 2011;doi:10.1167/iovs.10-5716.
Richdale K, et al. Optom Vis Sci. 2006;doi:10.1097/01.opx.0000216098.62165.34.
Sanfilippo PG, et al. Acta Ophthalmol. 2015;doi:10.1111/aos.12644.
Schuster AK, et al, Graefes Arch Clin Exp Ophthalmol. 2017; doi:10.1007/s00417-017-3775-x.
Situ P, et al. Eye Contact Lens. 2003;doi:10.1097/01.ICL.0000072827.42925.49.
Woods J, et al. Eye Contact Lens. 2009;doi:10.1097/ICL.0b013e3181b5003b.
Young G, et al. Eye Contact Lens. 2011;doi:10.1097/ICL.0b013e3182048fb9.

For more information:
Thomas G. Quinn, OD, MS, FAAO, is in private practice in Athens, Ohio. He can be reached at: tgquinn5@gmail.com.

Disclosure: Quinn reports he is a consultant for Alcon, Bausch + Lomb and Johnson & Johnson Vision Care; has received educational grants from ABB Optical, Gas Permeable Lens Institute and STAPLE Program of the Contact Lens Manufacturers Association; and has received research grants from CooperVision and Menicon.

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Choose the patient as well as the lens

Tom Arnold, OD, FSLS: With the emergence of a large cohort of contact lens patients who desire to continue wearing lenses for distance as well as near, the interest in multifocals has never been greater. We are all familiar with the challenges this entails. Patients have a variety of needs such as computers, smart phones, driving and distance activities. They also may have dry eyes, meibomian gland dysfunction, early cataracts or residual astigmatism. With regard to the latter, how do we go about selecting the proper lens?

Obviously, patient history, expectations and personality traits are critical to success. We don’t just pick the lens; we must pick the patient.

In attempting to correct an astigmatic presbyope we must consider such factors as horizontal visible iris diameter, lid position, partial blinking and, of course, topography to locate the source of the astigmatism – internal or external. Scleral lens fitting and orthokeratology have highlighted the need to look at elevation maps, as this may affect centration, which is critical to multifocal lens success. Many modern topographers can discern the difference between the visual axis and the pupillary axis, commonly referred to as angle kappa.

It is very important to center the multifocal optics, whether center-near or center-distance, over the visual axis. For this reason, manufacturers have started to offer decentered optics in custom soft, GPs and sclerals.

So, which to choose? Briefly, my thought process might look like this:

For a myope having with-the-rule astigmatism up to -1.50 D, some of which is internal, and low near demands, I would prescribe soft toric monovision.

For a myope or hyperope with oblique or against-the-rule astigmatism, especially with an internal component, I would choose a custom soft toric multifocal, monthly disposable if possible. Higher prescriptions are usually only available in quarterly replacement. Decentered optics may be available from some labs.

For a myope with corneal astigmatism, my recommendation is almost always a corneal multifocal GP or even a scleral lens. The multitude of design options make these very attractive for patients with significant demands. The practitioner’s confident recommendation of the features and benefits of GPs go a long way in patient acceptance.

The challenges are real, but the benefits are tangible. Specialty multifocal contact lenses can set you and your practice apart in today’s competitive environment.

For more information:
Tom Arnold, OD, FSLS, practices at Today’s Vision Sugar Land, Texas. He can be reached at: drarnold@2020sugarland.com.

Disclosure: Arnold reports that he speaks for Bausch + Lomb Specialty Vision Products, Blanchard Lab, Eaglet-Eye, EyePrint Prosthetics, Oculus USA and VTI Technologies. He is an advisory board member for the Gas Permeable Lens Institute and co-chair of the International Congress of Scleral Contacts.

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Use all options

Susan J. Gromacki, OD, MS, FAAO, FSLS: With both the Baby Boomers and Generation X now completely immersed in presbyopia, there are plenty of patients in our practices who require separate corrections for distance, intermediate and near. These are populations who have grown up wearing contact lenses and they do not want to stop. Those in this group with astigmatism are no different. Unlike the silent generation, they are fully aware of the technology around them and want to embrace it. When it comes to correcting their vision with contact lenses, they are unlikely to take “no” for an answer.

Fortunately, we have many options for these patients, and I use them all in my practice. They include: distance contact lenses with reading glasses, monovision, soft toric multifocals, corneal GP aspheric multifocals, scleral GP multifocals and corneal GP alternating multifocals.

Eighty-five percent of U.S. contact lens patients wear soft lenses, 24% of whom wear toric (Nichols et al.). Fortunately, there are currently 19 soft toric multifocal designs. They include aspheric center near (CN) and center distance (CD) and concentric CN and CD.

Astigmatic presbyopes can experience some visual compromise with soft toric multifocals, especially with high astigmatism and adds (Bergenske, Gromacki 2007). It is important to follow the manufacturer’s guides; they understand the nuances of their lenses and know how to enhance success.

The rigidity of corneal GP aspheric multifocals (CD or CN) provides optical benefits for an astigmatic presbyope. If the patient’s spectacle and corneal cylinders are within 0.75 D, and the corneal cylinder is less than 2 D to 3 D (depending on the design), a regular GP aspheric multifocal can be fitted. High residual astigmatism greatly increases the complexity of the fitting, because the lens has to be toric and presbyopic. High corneal cylinders require a back or bitoric; front surface torics can be placed on these lenses.

Aspheric designs provide intermediate corrections, and the fitting and troubleshooting can be straightforward. Many back surface aspherics are fitted like spherical GPs, with lid attachment. This design also translates, which enables utilization of the entire add. Optimal pupil size is also important; many designs customize the central zone size.

The advantages of scleral GP multifocals include less movement, larger optic zone and increased comfort. However, because they do not translate, the adds are predicated on pupil size and/or the patient’s ability to accept simultaneous vision. Also, they may decenter down and out, causing a misalignment of the visual axis and geometric center of the lens, leading to poor optics and/or acuity. Some designs have decentered optics to help.

Corneal GP alternating multifocals can contain almost any addition power. While aspheric lenses (corneal or scleral) are limited in add power by the technology that produces them, alternating bifocals are spherical and optically similar to single vision GPs (Gromacki 2006). For astigmatic presbyopes, a segment may be placed on the front of a back surface, front surface or bitoric GP lens design (according to personal communication with Bob Martin, Nov. 13, 2007).

Another advantage of alternating bifocal lenses is the virtual independence of pupil size. A disadvantage is the absence of intermediate correction. However, there are segmented trifocal/multifocals, and some labs can place an alternating, front surface add onto an existing back surface aspheric design.

In summary, multifocal contact lenses are a good option for astigmatic presbyopic patients. Although there are limitations, with proper patient selection, practitioner knowledge and the availability of various lens designs and materials, astigmatic presbyopic contact lens fitting can be both successful and rewarding.

References:
Bergenske PD. The presbyopic fitting process. Contact Lens Spectrum. 2001;16(8):34-42.
Gromacki SJ. Monovision and bifocal contact lenses. In: Hom MM and Bruce AS, eds. Manual of Contact Lens Prescribing and Fitting. St. Louis: Butterworth Heinemann; 2006:471-497.
Gromacki SJ. 2007 Soft toric contact lens update. Cont Optom. 2007;5(5):1-8.
Nichols JJ, Fisher D. Contact lenses 2018. Contact Lens Spectrum. 2019;34(1):18-23.
Tyler’s Quarterly Soft Contact Lens Parameter Guide. www.tylersq.com. Accessed January 25, 2019.

For more information:
Susan J. Gromacki, OD, MS, FAAO, FSLS, is director of the contact lens service at Washington Eye Physicians & Surgeons, Maryland, serves on the advisory board of the Gas Permeable Lens Institute and is on the medical advisory board for the International Keratoconus Academy. She can be reached at: Sgromacki3@hotmail.com.

Disclosure: Gromacki reports she has either received lecture compensation, travel compensation or attended an advisory board meeting for Alcon, Bausch + Lomb, Gas Permeable Lens Institute, Johnson & Johnson Vision Care and Shire.