International Myopia Institute: Recent Advances in Myopia Management

Myopia management is one of the most exciting areas in eye care today, with talks featuring at nearly every eye conference around the world. This is remarkable considering that it was only two to three decades ago when experiments in animal models revealed that plus and minus lenses could precisely modulate eye growth and also highlighted the significant role of the peripheral retina.

The IMI taskforce chairs reviewed and curated a number of key articles from the peer reviewed literature and conference abstracts published between 2019 to 2020 to provide the digest

Around this time, orthokeratology practitioners were also noticing that their paediatric patients were not progressing in myopia. These insights were translated into evidence-based treatment strategies that have gathered pace in recent years, leading to the development of many treatments to slow myopia.

The knowledge that myopia can be slowed has been transformational. The evidence for the impact of myopia is substantial; it is estimated that myopia prevalence will affect 50% of the global population by the year 2050, and high myopia will affect 10% of the population.1 Direct costs to the individual and society will increase substantially.^2,3

Today, we have reached the realisation that myopia is not a simple refractive issue, but an ocular condition requiring continuous management due to the associated risks of developing sight-threatening complications, such as myopic macular degeneration, retinal detachment, cataract and glaucoma. Despite the significance of myopia, myopia management remains relatively unknown in many parts of the world. One of the reasons is a lack of awareness of the impact of myopia by both practitioners and public alike. It is imperative that myopia management becomes the standard of care if we want to tackle the growing myopia epidemic.

Following the 2015 World Health Organisation and Brien Holden Vision Institute (WHO-BHVI) meeting on myopia and high myopia in Sydney, the IMI was established as a working group to continue the efforts to advocate for the need to address myopia as an ocular condition.

The IMI subsequently grew to over one hundred global experts, who together authored the IMI White Papers in 2019 and 2021. The first papers, published in 2019, brought consensus to the area of myopia management and research. Since then, over one thousand peer reviewed articles have been published on myopia. The IMI published the 2021 Yearly Digest report that provides key updates in the areas of definitions, experimental models, genetics, interventions, clinical management guidelines, and clinical trials that have occurred since the 2019 white papers. It aims to help practitioners stay abreast of the latest progress in the field. The IMI taskforce chairs reviewed and curated a number of key articles from the peer reviewed literature and conference abstracts published between 2019 to 2020 to provide the digest. Following are some of the most exciting updates in myopia from the Yearly Digest.

PRE-MYOPIA

To really reduce the burden associated with myopia, in addition to slowing myopia, prevention is important. Identifying those with pre-myopia, and addressing the risk of onset or managing when it first occurs, would be the key. Pre-myopia was a term that was first proposed in the 2019 IMI White Paper as “a refractive state of the eye between + 0.75D and better than – 0.50D in children where a combination of baseline refraction, age, and other quantifiable risk factors provide a sufficient likelihood of the future development of myopia.”^4,5 

This term is now increasingly adopted clinically and those at risk are also advised lifestyle changes, such as 120 minutes outdoors and reduced near-work intensity, according to the 20-20 rule (every 20 minutes of near viewing should be followed by looking into the distance of at least 20 feet [six metres], for 20 seconds). Presently, we can identify those with pre-myopia clinically and recommend lifestyle changes. In the future, we may also be managing them with interventions. A retrospective study reported a reduced myopic shift in children with premyopia treated with 0.025% atropine.⁶ Additionally, myopia intervention trials are underway in those with pre-myopia. An example is ATOM3, examining the ability of low-dose atropine in preventing myopia in those with pre-myopia.

AXIAL LENGTH PERCENTILE CURVES

Normative data for axial length, axial length/corneal curvature, as well as percentile curves for Chinese and European children have been published and provide information on the expected age and gender norms for specific populations.^7,8 These curves indicate where the length of an individual eye ranks in a given population based on ethnicity, age and gender. Based on their centile, one may be able to estimate their future risk for axial elongation and risk of myopia, high myopia or vision impairment. This is an exciting area of development as axial length measurements are accurate, rapid and non-invasive, and they provide an objective measure without the need for cycloplegia. Axial length percentile curves are clinically useful in monitoring axial length progression in myopia treatment, and some may compare this with measuring intraocular pressures (IOPs) for monitoring glaucoma treatment. There is also evidence indicating that axial length and axial length/corneal curvature data, when combined with age and gender, is useful in screening for myopia detection.⁹ Some of the axial length measurement devices currently available include axial length percentile curves and these allow the clinician to monitor paediatric eye growth, further improving our ability to manage patients. Axial length measurement should be considered in myopia management and will likely soon become the standard of care to monitor eye growth patterns/ treatment efficacy.

NEW TREATMENTS IN CHILDREN AND GREATER SLOWING WITH CURRENT OPTIONS

Innovations in optical strategies continue to deliver higher levels of efficacy than ever before; notably these include spectacle lens treatments incorporating discrete, multiple segments of positive power relative to the base lens. Recent data from a study that used multiple lens segments in the mid-periphery of the lens (Defocus incorporated multiple segment or DIMS), found a significant treatment efficacy of up to 60% over a two-year treatment period.10 Another entrant to this category is aspherical lenslets; the multiple lenslets are arranged around a central aperture that corrects for the distance refractive error and are said to result in myopic defocus at the retina. After one year of lens wear, highly aspherical lenslet (HAL) spectacles were able to slow myopia by 67% and 64% with regards to spherical equivalent refractive error and axial elongation respectively.

In comparison, slightly aspherical lenslet (SAL) spectacles were able to slow myopia by 41% and 31%, respectively.¹¹ In addition to these new entrants, several contact lens trials have established the efficacy of multifocal contact lenses in slowing myopia. In a three-year multicentre, randomised, clinical trial, MiSight contact lenses were able to slow myopia by more than 50% in terms of spherical equivalent and axial length.¹² The MiSight lens is approved by the United States Food and Drug Administration (FDA) for myopia control in children. In another randomised trial, lens designs based on the extended depth of focus (EDOF) principle, or multifocal designs imposing myopic defocus at both the central and peripheral retina, were found to slow myopia. Both the change in refractive error and axial length were significantly slower with the test lenses, and greater efficacy was observed with better wearer compliance.¹³ Additionally, in a three-year trial, a centre distance multifocal was found to significantly slow myopia. Myopia progression over three years was lower with a higher add (+2.50D) compared to a lower add (+1.50D).¹⁴ 

In pharmaceutical strategies, the LAMP study found a significant slowing of myopia over two years with 0.05%, followed by 0.025% and 0.01%. The efficacy of 0.05% and 0.025% were similar across both year one and year two; 0.01% improved slightly in year two but lagged overall in comparison to other concentrations.¹⁵ There were no clinically significant adverse effects reported for these concentrations. These new findings suggest that 0.05% or 0.025% is clinically better for myopia management compared to 0.01%, which showed little slowing in axial length. Additionally, there have been a number of trials that have evaluated the efficacy of 0.01% atropine plus orthokeratology (dual therapy) compared to orthokeratology alone (monotherapy) and found a significant slowing of axial length with dual therapy compared to monotherapy.^16,17 

FUTURE POTENTIAL TREATMENTS

Many of the current treatment strategies have their roots in evidence gathered from animal model work. Studies in experimental models remain an important contributor to myopia management options.

The role of IOP in myopia is a subject of investigation as it is hypothesised that IOP may be a contributing factor in progression in myopic eyes. It is theorised that myopic eyes may have a biomechanically weaker sclera and, therefore, be more susceptible to the stretching influence of IOP. The prostaglandin analogue, known as topical latanoprost (an IOP lowering drug in humans), reduced IOP over 24 hours in guinea pigs, and was effective in blocking axial myopia produced by form deprivation (myopia caused by depriving clear vision e.g., by using an occluder). The reduction in axial elongation correlated with the magnitude of IOP reduction.¹⁸

This early study demonstrates that eye growth is controlled by a variety of different pathways in the eye and provides an avenue for drugs that influence ocular biomechanics to slow myopia. Currently, there are other topical drugs, such as dopamine and caffeine, undergoing human clinical trials. The results of these are eagerly awaited as they offer more potential treatment options.

CONCLUSION

For eye care practitioners, as well as the optical and ophthalmic industry, the progress in the field of myopia presents a huge opportunity to provide improved and advanced patient care using the latest innovations in optical and pharmaceutical treatments. In addition to treatment strategies, there are innovations in instrumentation/devices to support myopia management. An example is advances in the area of optical biometers that provide both refractive and axial length measurements in a rapid, convenient, and objective manner. There is evidence to support prevention and slowing of myopia and we no longer need to wait to tackle this issue, given the known risks to vision with increasing levels of myopia. Every child that develops myopia of -0.50D should receive myopia management.

For further reading please refer to the full IMI 2021 Yearly Digest available at myopiainstitute.org/imiwhitepaper/ imi-2021-yearly-digest. The clinical summaries of the 2019 and 2021 IMI White Papers, and the full white papers originally published in Investigative Ophthalmology and Visual Science are available at myopiainstitute. org/imi-white-papers. The IMI Facts and Findings infographic is a useful patient communication tool and is available at myopiainstitute.org/resources. 

The International Myopia Institute is a non-profit project founded by the Brien Holden Vision Institute, and the resources are made freely available by sponsors Zeiss, Essilor, CooperVision, Alcon and Oculus. The IMI White Papers were co-authored by over one hundred leading experts in myopia who freely donated their time to support the mission of advancing myopia research and education, to prevent future blindness. 

Dr Monica Jong is the Global Director of Professional Education Myopia at Johnson and Johnson Vision Care and at the time of writing this article was the Executive Director of the International Myopia Institute (IMI), BHVI, Sydney. She is a visiting fellow of the School of Optometry and Vision Science, UNSW, Sydney, Australia, the honorary education advisor to the Asia Optometric Congress, and the secretary of the Refractive Error Working Group, International Agency for the Prevention of Blindness. Her research interests are in the field of refractive error, understanding myopia risk factors, myopia control, and the public health impacts. Dr Jong has co-supervised graduate students, authored numerous peer reviewed articles, and the WHO report on The Impact of Myopia and High Myopia. She also co-created the BHVI global online myopia management education program (first of its kind) and speaks regularly at key international meetings. 

Professor Padmaja Sankaridurg is Head, Myopia Program and Head, Intellectual Property at the BHVI, an IMI advisory board member, and Conjoint Professor at the School of Optometry and Vision Science, UNSW, Sydney, Australia. Prof Sankaridurg has been researching myopia for over 15 years with a focus on strategies to slow myopia. She participated as an expert at the WHO-BHVI global meeting of myopia, 2015, and is an advisory board member, Chair of Taskforce on Impact of Myopia and a member of the Interventions and Harmonisation Committee, International Myopia Institute. She is also an advisory board member for Review of Myopia Management, an online digital publication entirely devoted to myopia. Vision Monday named her as one of the ‘Women of Influence in Optical Industry Innovator section’ for 2018 and she is the recipient of the ‘International Optometrist of the year 2020’ awarded by the College Òptics-Optomeristes Catalunya (COOOC) and Associació Catalana de Teràpia Visual (ACOTV), Spain for her work in myopia. She has published extensively, is a co-inventor on many patents/applications, and has been instrumental in the development of many practice aids and guidelines, including the BHVI Myopia Calculator and the Oculus-BHVI percentile charts (orcid.org/0000-0001-5537-6193). 

References 

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