In Focus Blog

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SynergEyes In Focus Blog

At SynergEyes, we pride ourselves in delivering contact lens products that improve vision and ultimately enhance the quality of everyday life.

This blog is geared towards practitioners to highlight case studies from your peers and covers topics such as fitting & troubleshooting, as well helpful articles on practice management and the handling and care of SynergEyes lenses like Duette and UltraHealth.

The Science Behind Center Distance Optics for Myopia Control

By Louise Sclafani, OD

Myopia is a growing epidemic and practitioners are searching for options to slow myopia progression. Multifocal contact lenses offer young patients visual freedom from their spectacles while keeping myopic creep in check. Indeed, progression control is commonly achieved with center-distance designed multifocal contact lenses.

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While center-distance multifocals are not FDA-approved specifically for myopia control, several brands that are generally marketed toward presbyopes are readily available and frequently prescribed off-label by practitioners. These big box soft contact lens brands are a useful solution for young patients with uncomplicated prescriptions, average pupil sizes, and healthy ocular surfaces. For kids with astigmatism or a desire for high vision quality, gas permeable optics - like those delivered with hybrid lenses - provide another option. And now they are customizable to eye shape and pupil size. 

A Case for Multifocal Contact lenses

On average, multifocal contact lenses slow the progression of myopia by approximately 40%.1 This is in stark contrast to the effects seen in single-vision lens wearers. Compared to a control group of single vision lens wearers, research shows a 50% slower myopia progression in children with center-distance bifocal contact lenses.2

Multifocal lenses work by reducing a child’s peripheral hyperopic defocus, thereby eliminating the stimulus for axial elongation, which slows the myopia progression.3 Indeed, research shows these lenses reduce axial elongation by 29%.4

Why Center Distance?

Multifocals can help keep myopia from getting worse, but to be effective, the lenses must feature a "center-distance" design.5 The reason is fairly straightforward: Myopia-control center-distance multifocals have two distinct portions within the optical zone: a central portion that corrects for the distance refractive error and an outer zone that is relatively positively powered compared with the central portion.6 The relatively positive power is intended to reduce hyperopic defocus, induce myopic defocus or both across areas of the retina.7

Generally speaking, center-distance lenses limit the amount of disruption to the distance vision by having the portion of the lens over the visual axis containing the distance Rx blending into the bifocal power toward the periphery.8 However, there are significant variations in pupil diameter among individuals.9 That’s why it’s so important to offer your patients a unique lens for their unique eyes.

Center Distance Designs

While different soft contact lens designs have varying central distance diameters, the center distance zone size is usually fixed within each design.  Some lenses, such as Duette Progressive, offer a variety of customizable parameters to fit different corneal shapes and pupil sizes. The Duette Progressive Center Distance design features a technology called Center Distance FlexOpticsTM, which provides a more personalized vision solution to address variations in pupil diameter, making this lens customizable for each patient.   Since younger kids tend to have larger pupil sizes, now the distance zone can be tailored to their individual pupil size. Thanks to adjustable center distance optics, the Center Distance zone size ranges from 1.8 - 4.0mm, driven by photopic pupil size. Add powers range from +0.75 to +5.00 D.

Myopia is on the rise and solutions that will work for kids with all types of eyes are needed. The Duette Progressive Center Distance design provides uncompromised GP optics with soft skirt comfort, and is customizable, even for patients who have astigmatism.

References

1 Walline JJ, et al. Eye Contact Lens. 2016;42(1):3-8.

2 Walline JJ, et al. Multifocal contact lens myopia control. Optom Vis Sci, 2013. 90(11):1207-14. 

3 Henderson S. Clinicians anticipate distance-center multifocals for myopia control. Primary Care Optometry News, September 2017.

4 Walline JJ, et al. Optom Vis Sci. 2013;90(11):1207-1214

5 American Optometric Association. Multifocal contact lens effective at treating myopia in kids. APRIL 25, 2016. Available at: https://www.aoa.org/news/clinical-eye-care/multifocal-contact-lens-effective-at-treating-myopia-in-kids

6 Sankaridurg P. Fitting Multifocal Contact Lenses for Myopia Control. Review of Cornea and Contact Lenses, February 2017.

7 Sankaridurg P. Fitting Multifocal Contact Lenses for Myopia Control. Review of Cornea and Contact Lenses, February 2017.

8 Nixon G. Which Multifocal Design Is Best For Your Patients? Contact Lens Spectrum, December 2016.

9 Richdale K. Ocular and Refractive Considerations for the Aging Eye. Contact Lens Spectrum. February 2009.