February 1, 2021
By Monica Jong, BOptom, PhD
Prevalence of myopia and high myopia is increasing around the world, and in some parts of the world, it has already reached epidemic proportions.1 Thirty percent of the world’s population is currently myopic, and by the year 2050, fifty percent will be myopic, and 10 percent will be 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 blindness in parts of Europe and Asia.3 Clinicians will need to meet the challenge of an increasingly comprehensive eye care service that detects/diagnoses, corrects and slows myopia, and manages the complications. The costs from the lost productivity of uncorrected myopia as well as permanent vision loss from MMD alone totaled $250 billion in the year 2015,4 and it is set to rise in the future. Currently, we have treatments (off-label and approved) to slow myopia progression, but we also need to consider prevention. Based on known risk factors for myopia and a proposed definition for pre-myopia by the International Myopia Institute,5 we have a good basis to start evidence-based preventative eye care.
The International Myopia Institute5 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.”
Following a comprehensive eye examination where you have taken a thorough history, conducted cycloplegic refraction, and ruled out any other ocular condition, and you find your patient has less hyperopia than expected for their age, with any of the risk factors below, then you can consider them to be 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.6
Reduced time outdoors and increased near work – clinical trials have reported that increasing additional time outdoors to at least 80 minutes per day is protective against new cases of myopia7, 8 while intense near work is associated with increased risk of myopia.9 10
Urban environment – those living in dense cities tend to have a higher risk than in rural or suburban settings,11 as urban environments are linked to less time spent outdoors and more near work activity.
Currently, there is no strong evidence to start optical and pharmacologic treatments in a pre-myope. Studies such as the currently underway ATOM3 trialing low-dose atropine in pre-myopia will guide us in the management of pre-myopes in the near future. For now, we should be advising increased time outdoors of at least 80 minutes daily (with sun protection) and reduced near work to less than 2.5 hours per day.12 Regular yearly review as a minimum would be recommended for a child that is significantly at risk of developing myopia. This advice should form part of the comprehensive management of a child with myopia too.
Future Objective Measures
Tools such as apps and smart devices worn on frames or as a watch have been trialed to quantify near work hours, posture, and time outdoors. (IMI Environmental risk factors, to be published in IOVS 2021) These could eventually be used to support the management of our patients. Axial length growth charts have been published for European13 and Chinese14 children, and axial length normative data is already being used in biometers such as the Haag-Streit Lenstar Myopia and Oculus Myopia Master.
Much discussion has been directed about using axial length measurement as a critical measurement for myopia management. It is objective, fast, accurate, and easily performed with many of the automated devices available on the market today. When there is more understanding about the precise relationship between axial length and refractive error, it may become the gold standard for clinical management – it is currently a key outcome measure in clinical trials.
Myopia management is an exciting area with new research and technology advancements that will allow us to detect the pre-myope earlier and more accurately manage pre-myopia. Today, we can detect pre-myopia, potentially prevent myopia, and address myopia’s serious public health challenge.
Monica Jong, B. Optom, PhD, is Executive Director, International Myopia Institute, BHVI, Sydney, Australia; Assistant Professor Discipline of Optometry and Vision Science, University of Canberra, ACT, Australia; and Visiting Fellow, School of Optometry and Vision Science, UNSW.
- Morgan IG, He M, Rose KA. EPIDEMIC OF PATHOLOGIC MYOPIA: What Can Laboratory Studies and Epidemiology Tell Us? Retina 2017;37:989-997.
- 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.
- 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.
- Naidoo KS, Fricke TR, Frick KD, et al. Potential Lost Productivity Resulting from the Global Burden of Myopia: Systematic Review, Meta-analysis, and Modeling. Ophthalmology 2019;126:338-346.
- Flitcroft DI, He M, Jonas JB, et al. IMI – Defining and Classifying Myopia: A Proposed Set of Standards for Clinical and Epidemiologic Studies. Invest Ophthalmol Vis Sci 2019;60:M20-M30.
- Jones LA, Sinnott LT, Mutti DO, Mitchell GL, Moeschberger ML, Zadnik K. Parental history of myopia, sports and outdoor activities, and future myopia. Invest Ophthalmol Vis Sci 2007;48:3524-3532.
- Wu PC, Tsai CL, Wu HL, Yang YH, Kuo HK. Outdoor activity during class recess reduces myopia onset and progression in school children. Ophthalmology 2013;120:1080-1085.
- Wu PC, Chen CT, Lin KK, et al. Myopia Prevention and Outdoor Light Intensity in a School-Based Cluster Randomized Trial. Ophthalmology 2018;125:1239-1250.
- 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.
- Lanca C, Saw SM. The association between digital screen time and myopia: A systematic review. Ophthalmic Physiol Opt 2020;40:216-229.
- 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.
- Gifford KL, Richdale K, Kang P, et al. IMI – Clinical Management Guidelines Report. Invest Ophthalmol Vis Sci 2019;60:M184-M203.
- Tideman JWL, Polling JR, Jaddoe VWV, Vingerling JR, Klaver CCW. Environmental Risk Factors Can Reduce Axial Length Elongation and Myopia Incidence in 6- to 9-Year-Old Children. Ophthalmology 2019;126:127-136.
- 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.