ZEISS Vision Care has more than a decade of experience developing lenses to manage myopia. Now the company is bringing its new MyoCare lens innovation to Australia and New Zealand – an age-related solution comprising two lens design options.
One of the key challenges for manufacturers developing spectacles lenses for myopia management is finding the optimal compromise. It’s the sweet-spot, accounting for the interplay between a maximised treatment zone, together with a minimised central zone that provides clear vision, while ensuring the control effect is maintained at all gaze angles.
Once satisfied, these elements address a fourth factor: wear time – a major contributor for putting the brakes on myopia, with increasing efficacy for longer hours of daily wear.
Two new myopia spectacle lens designs from ZEISS Vison Care have been designed with these requirements in mind, seeing the company become the latest to bring a lens to market for progressing myopes in Australia and New Zealand.
The company’s ZEISS MyoCare lenses will be released to Australian and New Zealand optometry practices in July 2023. The company has developed a unique, patented design (which will be detailed later in this article), but of more interest to ophthalmic professionals is the way in which ZEISS is structuring the portfolio.
It’s taking a different approach by offering an “age-related myopia management lens solution”. This involves two distinct designs: one for children under the age of 10 (ZEISS MyoCare with a 7 mm diameter clear zone), and another for children 10 and older (ZEISS MyoCare S with a 9 mm diameter clear zone).
“These represent a softer and a harder version of the ZEISS MyoCare lens design, respectively,” Ms Elmarie Pretorius, professional services manager for ZEISS Vision Care Australia & New Zealand, says.
“Two prototypes went into trials in China, and after six months the intention was to release one to the wider market, and that was the harder design with a smaller central zone and a higher plus in the periphery (ZEISS MyoCare).
“But when we received our 12-month results, there was a clearly stated graph that showed a strong emmetropic growth ratio in the 6-9 years age group with our harder ZEISS MyoCare design. But this further improved significantly in the 10 and older age group with the softer design (ZEISS MyoCare S). That’s why we are launching an age-specific solution.”
While ZEISS MyoCare lenses represent one of the latest innovations in Australian myopia care, the company has had a presence in this space for some years. Eyecare professionals may be familiar with ZEISS MyoVision Pro lenses – a single vision option for children between the ages of six and 12.
The older ZEISS MyoVision lenses were based on peripheral defocus, but Pretorius says the research now points to the concept of “simultaneous competing defocus” as inhering a stronger growth stop signal in myopia.
Based on these developments, ZEISS’ R&D department has incorporated significant improvements in the new ZEISS MyoCare portfolio, which has been inspired by the ring-like imprints on the cornea following orthokeratology treatment.
In terms of efficacy, both ZEISS MyoCare lens design variants are now the subject of a multi-centre randomised controlled two-year clinical trial to assess their safety and effectiveness. Pretorius says the latest data after 12 months shows participants wearing the ZEISS MyoCare design are 63% closer to the emmetropic growth curve. Meanwhile, those wearing ZEISS MyoCare S were 86% closer to normal emmetropic growth. (NOTE: be mindful when comparing data. Other lens designs may compare to control groups, for example).
To achieve this, ZEISS MyoCare’s design adopts annular cylindrical microstructures to induce simultaneous competing myopic blur on the peripheral retina to slow myopia progression. The company’s patented Cylindrical Annular Refractive Elements (C.A.R.E.) Technology incorporates alternating defocus and correction zones expanding towards the periphery of the lens. These elements are so small in dimension that special optical methods are required to make them visible.
“What also makes the ZEISS MyoCare lens unique is the use of a cylindrical shape in the functional zone, where the height, width and size of the microstructures creates the blur effect as part of simultaneous competing defocus,” Pretorius says.
“As opposed to a normal spherical or aspherical lenslet in the treatment zone, our approach means that light coming in and falling on that cylindrical shape causes a blended distribution of blur, which is less perceived by the child, helping to improve adaptability and wearability of the lens, while creating the strongest stop signal to prevent the eye elongating.”
Treatment effect at all gaze angles
Compared to contact lenses and ortho-k, spectacle lenses are thought to offer distinct advantages as a myopia management intervention in children. They are easy-to-fit, affordable, mostly well accepted and tolerated, and minimally invasive.
But to make spectacle lenses work for myopia control, it requires some clever optical science that equally accounts for a treatment zone that slows myopia progression, as well as a clear zone that provides sharp vision to correct the patient’s refractive error.
With a 9 mm diameter of the clear zone for MyoCare S and a 7 mm diameter for ZEISS MyoCare, the clear zone needs to provide enough space for children to pursue their typical daily activities without any accommodation issues during near tasks like reading or writing. At the same time, ZEISS realised the need to keep the clear zone as small as possible to establish an effective functional zone projecting myopic defocus on the near peripheral retina close to the fovea.
The lens also needs to account for constant movement of the eye, ensuring the intended correction and myopic defocus is maintained for all gaze angles.
Pretorius says ZEISS addresses this by using ClearFocus design, a freeform back surface that not only provides the correct lens power for all viewing angles, but minimises unwanted hyperopic defocus independent of gaze direction.
“With a standard back surface, when a patient looks on an angle or to the side, they’re potentially not getting the same level of effectiveness compared to a flatter back surface,” Pretorius says.
“Because we’ve got a freeform back design, we’re able to minimise unintended hyperopic defocus for oblique views through the lens periphery.”
Australia and New Zealand launch
ZEISS MyoCare has been in use in China for more than a year, and became available in Europe in April 2023. The longer wait for Australian optometry practices means local eyecare professionals can access the lenses in 1.5, 1.6 and 1.67 indexes, as opposed to only 1.59 index (polycarbonate).
Australian and New Zealand optical practices can expect several ZEISS MyoCare launch events across the country, in addition to promotional events in collaboration with eyewear companies that have designed frames for myopia control lenses.
“These frames will feature markings to ensure the lenses are dispensed in the correct fashion,” Pretorius says.
“We also know a lot of optometrists are confident in managing myopia, but many others wanting to get started might be lacking confidence or are unsure where to start. We will be creating material to help them understand the lens technology, as well as how to communicate its benefits to patients.”
In addition to this, Pretorius says ZEISS will be releasing a seven-part webinar series to help optical dispensers and assistants improve their myopia knowledge. The launch events will be CPD-accredited for optometrists, and the company will be speaking to ophthalmologists to ensure they have an understanding of the ZEISS MyoCare design.
ZEISS is also putting the final touches on an attractive warranty structure, as an indication of its confidence in the product, Pretorius says.
Myopia – a global issue
ZEISS recognises the magnitude of the myopia problem. However, years of research show that prevalence differs and the risks associated with progressive myopia require specific solutions for different target groups.
It’s predicted myopia prevalence will climb to 50% by 2050. Despite being a global challenge, there are regional differences. For example, up to 90% of the urban youth of 20 years and younger are affected in Southeast Asia, while rates in Europe are much lower. Currently, 36% of Australians and New Zealanders are estimated to have myopia, but this could rise to a staggering 55% by 2050, with Australia expected to have 4.1 million high myopes by then.
With much of the research emerging from East Asian countries, the company set out to understand the refractive development in Caucasian children.
In 2014, ZEISS partnered with the Leipzig Research Center for Civilization Diseases of the University of Leipzig which started the LIFE Child study in 2011 – one of the biggest population-based longitudinal cohort studies in Europe. The study monitors child development from birth to adulthood and to understand factors associated with health and disease. The so-called ‘eye health cohort’ now consists of approximately 2,000 children aged between three and 16 years. These participants are invited to attend annual follow-ups where refraction, visual acuity and axial length of the eye are recorded and monitored longitudinally.
Separately, ZEISS partnered with Euronet Market Research to analyse ocular history data collected in over 400 optician shops across Germany from more than 500,000 subjects aged between 0 and 20 years to validate that the study results reflect what is observed in real-world eyecare practices.
The combined insights from these studies point to a trend of increasing myopia prevalence in Europe – similar to what is seen in North America, India and Australia, but to a much smaller extent than what is observed in East Asia.
“We looked at the refractive development of the eye from kids across multiple multicultural ethnicities, and concluded they’re very similar in how they develop, so it appears to be the influence of genetics and external factors driving higher prevalence in East Asia,” Ms Elmarie Pretorius, professional services manager for ZEISS Vision Care Australia & New Zealand, says.
“Because we’ve seen that myopia is rising across the world, as a company we decided to do more about it, and that’s provided the research and basis of our new lens design.”