Myopia, pre-myopia and shifting paradigms in the standard of care

At the completion of this article, the reader should be able to improve their myopia management practices, including: 

•  Appreciate the importance of integrating axial length measurement into myopia management protocols for early detection and monitoring.

•  Consider the implementation of the World Council of Optometry’s ‘three M’s’ approach (Mitigation, Measurement, Management) as a framework for evidence-based myopia care.

•  Evaluate the clinical benefits and challenges of using axial length measurement in conjunction with traditional refractive error assessments.

Monica Jong
PhD, BOptom, FBCLA
Visiting fellow UNSW, Sydney, Australia
Global director professional education myopia, Johnson & Johnson Medtech, Jacksonville, USA
Former executive director, International
Myopia Institute

Optometrists are adapting their myopia management strategies amid rising prevalence. With an increasing emphasis on the detection of pre-myopia, there has also been a growing consensus on the importance of integrating axial length measurement with traditional refractive error assessments. DR MONICA JONG examines the emerging standards of care in myopia management.

The prevalence of myopia and high myopia is increasing around the world, and in some parts, it has already reached epidemic proportions.¹ Thirty per cent of the global population is currently myopic, and by the year 2050, 50% will be myopic, and 10% highly myopic.² 

As a consequence of the increase in myopia and high myopia, there will be an increase in permanent sight-threatening ocular complications such as myopic macular degeneration (MMD), already a leading cause of vision impairment and blindness in parts of Europe and Asia.³ 

Eyecare professionals will need to meet the challenge of an increasingly comprehensive eyecare service that detects and diagnoses, corrects and slows myopia, in order to help mitigate future visual impairment from progressive myopia. The costs from the lost productivity of uncorrected myopia, as well as permanent vision loss from MMD, alone totalled approximately $250 billion in the year 2015,⁴ and it is set to rise in the future.

Currently, we have treatments to slow myopia progression, but we also need to consider prevention as that could lead to the greatest public health impact overall. Based on known risk factors for myopia and a proposed definition for pre-myopia by the International Myopia Institute,⁵ a committee chaired by Professor Ian Flitcroft, we have a good basis to start evidence-based preventative myopia management.

Pre-myopia defined

‘Pre-myopia’ is a term understood to describe a patient with a nonmyopic refraction who has a combination of myopia risk factors and an observed pattern of eye growth that indicates a high risk of progression to myopia.

The International Myopia Institute (IMI) defines pre-myopia as “a refractive state of an eye of ≤ +0.75 D and > -0.50 D in children where a combination of baseline refraction, age, and other quantifiable risk factors provide a sufficient likelihood of the future development of myopia to merit preventative interventions”. ⁵ 

As the IMI notes,⁵ most forms of myopia progress from onset for a variable period. Currently, reducing the rate of progression is a central goal of myopia research, but preventing the onset of myopia may be an even more valuable target.

As the Collaborative Longitudinal Evaluation of Ethnicity and Refractive Error (CLEERE) study has demonstrated, eyes destined to become myopic show an accelerated pattern of axial elongation several years before the onset of myopia.⁶  But the best indicator of pre-myopia remains the baseline refraction – in other words, the level of refraction expected for age. For example, based on a multi ethnic study, a six-year-old should have at least +0.75 D of hyperopia otherwise they have pre-myopia. ⁷

Assessing risk factors

Following a comprehensive eye examination where the optometrist has taken a thorough history, conducted cycloplegic refraction and ruled out any other ocular condition – and the patient is found to have less hyperopia than expected for their age with any of the risk factors below – then the patient can be considered ‘pre-myopic’.

•  Ethnicity – we see a higher prevalence of myopia in certain ethnic groups. East and Southeast Asians have a higher prevalence of myopia compared with Europeans, Africans, and Indians.¹

•  Parental myopia – one myopic parent increases the risk three times, and two myopic parents increase the risk six times.⁷

•  Reduced time outdoors and increased near work – clinical trials have reported that increasing additional time outdoors to at least 120 minutes per day is protective against new cases of myopia^{8, 9, 10} while intense near work is associated with increased risk of myopia.^11,12

•  Urban environment – those living in dense cities tend to have a higher risk than in rural or suburban settings,¹³ as urban environments are linked to less time spent outdoors and more near work activity.

Managing Pre-Myopia

Currently, there is no strong evidence to start optical and pharmacologic treatments in a pre-myope but we are seeing emerging studies in this so guidance may likely change in future.

Regular yearly review as a minimum would be recommended for a child that is significantly at risk of developing myopia. (As discussed below, axial length measurement should be considered). For now, we should be advising increased time outdoors of at least 120 minutes daily (with sun protection) and reduced near-work to less than 2.5 hours per day.¹³ This advice should form part of the comprehensive management of a child with myopia too.

Objective measures

Much discussion has been directed about using axial length measurement as a critical measurement for myopia management. Measured in millimeters from the anterior cornea to the retinal pigment epithelium, axial length (AL) has emerged as the most significant contributor to refractive error and potential myopia-related visual impairment.¹⁴

Measurement of AL is objective, fast, accurate, and easily performed with many of the automated devices available on the market today. AL growth charts have been published for European^{15, 18} and Chinese¹⁵ children, and AL normative data is being used in various axial length biometers such as the Haag-Streit Lenstar Myopia and Oculus Myopia Master.

Traditionally, AL measurement hasn’t been mainstream in optometry. However, as optometrists who routinely use OCTs know, standards of care and the adoption of new technologies can, and do, evolve rapidly. And just as OCTs revolutionised the management of ocular diseases in optometric practices, many are now considering integrating AL measurement into their myopia management protocols.

The benefits of AL measurements are significant although not mandatory to get started in myopia management:

•  Establishing baselines: baseline AL measurements allow us to track changes over time.

•  Patient education: incorporating AL measurement data into discussions with parents, caregivers and patients about myopia severity, encouraging proactive involvement in their eye health.

As the clinical benefits of AL measurements expand, it is becoming helpful to integrate these data with established myopia risk factors. While it would be unwise to simply reduce ‘myopia management’ to ‘axial length management’,¹⁹ it is undeniable that the data derived from AL measurements will increasingly shape optometric decision-making in pre-myopia and myopia care.

To be clear: a comprehensive evaluation that includes refractive error assessments is still essential for accurate myopia diagnosis and personalised patient care. AL measurements augment, not replace, a comprehensive eye examination.

World Council of Optometry

The Brien Holden Vision Institute (BHVI) has played a significant role in defining the myopia epidemic through its research and advocacy efforts and has been pivotal in redefining myopia as a public health issue. I have had a great opportunity to work with leaders in driving these initiatives, in particular the late Professor Brien Holden, Professors Serge Resnikoff and Earl Smith as well as partnering with the IAPB and World Health Organization and in the context of uncorrected refractive and accessibility which remains something that all industry partners can help to address collectively with their new innovations in this space.

Summary

Today, myopia can no longer be seen as a harmless refractive error with minimal long-term impacts on eye health. Other organisations have followed suit. In 2021, The World Council of Optometry (WCO) unanimously adopted a resolution¹⁹ advising optometrists to “regularly and consistently offer scientifically proven myopia interventions within their practices”.

In the resolution, the WCO defined the ‘evidence-based standard of care for myopia’ as comprising of three main components, which they called the ‘three Ms’:²⁰

•Mitigation
optometrists should educate and counsel parents and young patients, during early and regular eye exams, on lifestyle/dietary/other factors to prevent or delay onset of myopia.

•Measurement

optometrists evaluating the status of a patient during regular comprehensive vision and eye health exams, (including refractive error and AL measurements whenever possible).

•Management
optometrists addressing patients’ needs of today by correcting myopia, while also providing evidence-based interventions (e.g., contact lenses, spectacles, pharmaceuticals) that slow the progression of myopia, for improved quality of life and better eye health today and into the future.

The WCO’s resolution further recommended that optometrists adopt a standard of care that goes beyond vision correction to include patient education and early, frequent discussions with parents to explain:

•  what myopia is

•  lifestyle factors that may impact myopia

•  the increased risks to long-term ocular health that myopia brings

•  the available approaches that can be used to manage myopia and slow its progression.

In essence, this closes the debate on myopia which Brien Holden (et al.) launched as far back in 2015 when they argued that the time has come to change our understanding of myopia from merely as a benign refractive error to a condition with profound long-term implications for eye health worldwide.²¹

Eyecare professionals have shifted from merely correcting vision and refractive errors to adopting evidence-based myopia management strategies. This includes educating patients on ways to prevent myopia and discussing research-backed management options to slow its progression. 

Ultimately, an approach integrating clinical and lifestyle factors is essential for accurate diagnosis and optimal ongoing management of paediatric myopia. With myopia’s escalating prevalence comes a rise in severe ocular conditions like myopic macular degeneration, contributing significantly to economic costs and vision impairment.^3,4

All of us have the opportunity change a child’s life for the better today and in future.  Being able to predict, manage and mitigate myopia and the risks of associated complications is something we all can do today.   

More reading 

Ménière’s disease: a primer for optometrists

Accommodation disorders: Recognising, assessing and managing

Dry eye: Patient identification, product formulation and therapy escalation

References

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2.Holden BA, Fricke TR, Wilson DA, et al. Global Prevalence of Myopia and High Myopia and Temporal Trends from 2000 through 2050. Ophthalmology 2016;123:1036-1042.

3.Haarman AEG, Enthoven CA, Tideman JWL, Tedja MS, Verhoeven VJM, Klaver CCW. The Complications of Myopia: A Review and Meta-Analysis. Invest Ophthalmol Vis Sci 2020;61:49.

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9.Wu PC, Chen CT, Lin KK, Sun CC, Kuo CN, Huang HM, Poon YC, Yang ML, Chen CY, Huang JC, Wu PC, Yang IH, Yu HJ, Fang PC, Tsai CL, Chiou ST, Yang YH. Myopia Prevention and Outdoor Light Intensity in a School-Based Cluster Randomized Trial. Ophthalmology. 2018 Aug;125(8):1239-1250.

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11.Huang HM, Chang DS, Wu PC. The Association between Near Work Activities and Myopia in Children-A Systematic Review and Meta-Analysis. PLoS One 2015;10:e0140419.

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13.Lanca C, Saw SM. The association between digital screen time and myopia: A systematic review. Ophthalmic Physiol Opt 2020;40:216-229.

14.Tideman, J.W., et al., Association of AL with Risk of Uncorrectable Visual Impairment for Europeans With Myopia. JAMA Ophthalmol, 2016. 134(12): p. 1355-1363.

15.Saw SM, Hong RZ, Zhang MZ, et al. Near-work activity and myopia in rural and urban schoolchildren in China. J Pediatr Ophthalmol Strabismus 2001;38:149-155.

16.Gifford KL, Richdale K, Kang P, et al. IMI – Clinical Management Guidelines Report. Invest Ophthalmol Vis Sci 2019;60:M184-M203.

17.Tideman JWL, Polling JR, Jaddoe VWV, Vingerling JR, Klaver CCW. Environmental Risk Factors Can Reduce AL Elongation and Myopia Incidence in 6- to 9-Year-Old Children. Ophthalmology 2019;126:127-136.

18.Sanz Diez P, Yang LH, Lu MX, Wahl S, Ohlendorf A. Growth curves of myopia-related parameters to clinically monitor the refractive development in Chinese schoolchildren. Graefes Arch Clin Exp Ophthalmol 2019;257:1045-1053.

19.Should myopia management be renamed as AL management? [Internet]. The New Optometrist. [cited 2024 Jul 14]. Available from: https://www.thenewoptometrist.com/features/the-case-for-axial-length-measurement

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