Get a rapid-fire rundown of considerations for multifocal lens success
Multifocal contact lenses are advancing fast in the contact lens market, and optometrists may be surprised at their applications. This topic was discussed at a rapid-fire session at the American Academy of Optometry 2019 annual meeting in Orlando.
• Beth Kinoshita, OD, FAAO, at Pacific University College of Optometry
• Vinita Henry, OD, FAAO, at the University of Missouri-St. Louis College of Optometry
• Dawn Lam, OD, FAAO, at Southern California College of Optometry at Marshall B. Ketchum University
• Julie DeKinder, OD, FAAO, at the University of Missouri-St. Louis College of Optometry
Soft multifocal considerations
A crucial aspect of fitting soft multifocal contact lenses, according to Dr. Kinoshita, is good centration.
With single-vision (SV) contact lenses, there is some room for error in centration. But in multifocal lens designs, specific optics can help the lens center over the visual axis. Thus, centration is more important for a proper fit.
“Today’s off-the-shelf contact lenses provide many of these features,” she says.
Fitting considerations for multifocal contact lenses are anatomical, so ODs should take care to ensure good coverage and movement.
“I challenge ODs in practice to really start looking at the decentration, though slight, of their contact lens fits,” Dr. Kinoshita says.
She says that in her experience, many contact lens patients seen in previous evaluations appeared to be properly centered, but in actuality had temporal displacement. While challenges like centration are less of a concern for monovision fits, other aspects, such as pupil size, become more significant.
Dr. Kinoshita recommends that ODs perform topography over the contact lenses to determine centration.
“This is best achieved if ODs perform topography on the patient without a contact lens and repeat the topography while the patient is wearing the multifocal lenses,” she says.
GP multifocals, aspherics, & translation
For both aspheric and translating gas permeable (GP) multifocal designs, a physical assessment is crucial to a proper fit.
“The lid position is going to be very important with these types of lenses,” Dr. Henry says.
She recommends that before fitting any GP lens, ODs take care to perform all necessary pre-fit evaluations, including:
• Physical exam of tears, cornea, lid
• Anterior and posterior health assessments
• Current refraction and add values
• Keratometry (K) values
• Dominant eye identification
• Pupil size measurements
• Horizontal visible iris diameter (HVID) measurements
• Lower lid position
Aspheric GP multifocals work best on patients with smaller pupils, though lower lid sizing is less of a factor.
“Typically, these will be a little more difficult if the patient requires critical near vision,” Dr. Henry says.
She recommends that ODs follow the GP laboratory’s fitting guide or manufacturer guidelines as references when using aspheric multifocals.
For translating designs, add power and pupil size are less of a concern, but ODs should note that the ideal patient will have a lid that is at or slightly above the lower limbus. Good lid tonicity helps as well.
Dr. Henry warns that ODs should be on the lookout for potential challenges like excessive lens rotation, poor translation, and near or distant blur.
Multifocal lenses for myopia control
Projections estimate that by 2050, five billion people will have myopia.1
However, new lenses for myopia control have the potential to stem this tide. Research into optical correction shows that certain contact lens designs can slow myopia by 36 to 79 percent.2-4
While applicable to all patients, lenses that slow refractive progression may offer particular value to myopic children. Typically, children as young as age 8 may wear contact lenses, though Dr. Lam notes that this range depends on the patient.
“Look at the maturity level of the patient and cooperation among parent, guardian, and child,” she says.
She describes key considerations when fitting patients with reshaping contact lenses to control myopia progression.
• Choose spherical-equivalent distance power from the fitting set
• Choose the highest tolerable add power
• Look for patients with low levels of refractive astigmatism
• Choose among daily, two-week, and monthly wear schedules
Dr. Lam notes that while these myopia control lenses have produced results for slowing myopic progression, they are not approved by the U.S. Food & Drug Administration (FDA) for this purpose. Practitioners should make these distinctions clear to patients and establish expectations going in.
Multifocal scleral fitting
Practitioners hoping to fit multifocal scleral lenses for patients have some obstacles.
“It’s a bit of a challenge,” Dr. DeKinder says.
Not all scleral lenses have a multifocal option, meaning that ODs need to think long-term when fitting patients in sclerals. In particular, they should consider the patient’s age and possible refractive progression.
“If you have a patient who is already presbyopic or may become presbyopic within the next few years, you need to make sure the lens you are selecting has the option for a multifocal design,” Dr. DeKinder says.
She also says that a well-fitting scleral lens will not move with blinking, so ODs must take care to ensure that the lens fits the pupil well. Scleral lenses, in general, will decenter when they are placed on the eye.
Again, Dr. DeKinder recommends that providers reference fitting guides to help make determinations.
Designs for these lenses can be concentric or aspheric, but it is possible to find combination lenses that offer more customization options.
“If you can get a lens with a center-distance or center-near design, you have more flexibility in the way you can manipulate those optics,” she says.
Overall, Dr. DeKinder recommends practitioners have a systematic approach and gain experience fitting different types of designs, one at a time.
“When you feel very good at fitting one, add a second lens design into your toolbox,” she says.
1. Holden BA, Fricke TR, et al. Global prevalence of myopia and high myopia and temporal trends from 2000 through 2050. Ophthalmology. 2016;123(5):1036-42.
2. Anstice NS, Phillips JR. Effect of dual-focus soft contact lens wear on axial myopia progression in children. Ophthalmology. 2011;118: 1152Y61.
3. Sankaridurg P, Holden B, et al. Decrease in rate of myopia progression with a contact lens designed to reduce relative peripheral hyperopia: one-year results. Invest Ophthalmol Vis Sci. 2011;52:9362Y7.
4. Aller TA, Wildsoet C. Results of a one-year prospective clinical trial (CONTROL) of the use of bifocal soft contact lenses to control myopia progression. Ophthal Physiol Opt. 2006 Nov;26:8Y9.