Managing the young adult with progressing myopia can be a difficult clinical task. Although commonly encountered, there is minimal data available to support evidence based practice. Most studies of myopia control interventions recruit participants aged between six and 14, with -1.00 to -5.00D of myopia. This means that any patient in your chair who falls outside of these ranges (e.g. all progressing adult myopes) sits in the realm of ‘typical results may not apply’. This article summarises what we know of myopia progression in adults and how best to manage it.
WHEN DOES MYOPIA STABILISE?
There is a small amount of research data available on the typical age for myopia stabilisation. The large scale Correction of Myopia Evaluation Trial (COMET)1 followed children for up to 11 years and plotted individual function curves to analyse the cessation of their refractive progression. The mean age of myopia stabilisation was 15.6 ± 4.1 years and the mean final refraction was -4.87 ± 2.01D. Across the group of almost 500 individuals of diverse ethnicities, it was found that:
- 48% had stable myopia by age 15 years,
- 77% by age 18 years,
- 90% by age 21 years, and
- By age 24 years, 96% had achieved the curve-based definition of myopia stabilisation.
one-fifth of myopes in their 20s will likely experience significant progression of at least 1D
This indicates that myopia management should likely continue into early adulthood. At age 18, while three-quarters of myopes are stable, a significant one-quarter are still progressing. In this cohort, the only significant factor associated with stabilisation of myopia at an earlier age was ethnicity (with African American children stabilising earliest; and Asian, Hispanic, Mixed and Caucasian children stabilising similarly). The amount of myopia at stabilisation was influenced by ethnicity (with African American children having 1.09D less final myopia than Asian children) and having two myopic parents (0.94D more final myopia than children with one or no myopic parents). Gender was not a significant factor in stabilisation.1
A further analysis of the COMET data set found that in the 15 year-old cohort, half of which had stable myopia and half of which were still progressing, there was no difference in their self-reported time spent on outdoor activities, which were an average of nine hours per week. The average time spent on near-work activities was 21 hours per week. It was found that each hour per week spent on nearwork activities was associated with a 2% decreased odds of stable myopia at age 15.2
HOW FREQUENTLY DOES MYOPIA PROGRESS IN YOUNG ADULTS?
Scientific research only provides a couple of insights into this important question. Firstly, a retrospective study of myopia progression in 815 single vision distance contact lens wearers aged 20–40 years3 found that 21% progressed by at least -1.00D over the five-year follow up period. In wearers aged 20–25 years, almost half progressed by at least -0.75D over five years, which reduced to only 25% in those aged 35–40. Table 1 provides data reproduced from this study, published by Bullimore et al.3 This retrospective data has some limitations – it was produced from a single contact lens industry research clinic that was unlikely to be using cycloplegic refraction methods, and without information available on factors such as strabismus or visual acuity. Axial length was not measured, and in fact no data is available in the literature on axial length increases in adult myopia progression. Nevertheless, this is valuable data indicating that myopia cannot be presumed stable in adulthood.
The longest available data on adult myopia progression comes from Finland and encompasses up to 23 years of follow up, from myopia onset at age eight to 12 years and into adulthood, for almost 150 individuals. All baseline examinations were performed by the same ophthalmologist, (the lead author on the research), using cycloplegic subjective refraction techniques.
The outcome reported was that mean myopia progression in the decade of the 20s was -0.45D ± 0.71D. While visually significant in itself, this represented a mean annual progression of only -0.05 ± 0.09D. In almost half of cases, progression was more than -0.50D over a decade and in 18%, myopia increased by 1D or more.4 Again, an association was found between having one or two myopic parents and higher final myopia. At the final follow up (average age 31 years), there was no relationship found between final myopia and time spent on near-work in either childhood or adulthood, academic attainment (last grade point average at school) or years of education.
The sum total of these observational studies are that one-fifth of myopes in their 20s will likely experience significant progression of at least 1D.
HOW SHOULD ADULT MYOPIA PROGRESSION BE MANAGED?
Three key considerations for management of adult myopia progression are monitoring eye health, providing myopia correction, and attempting myopia control.
Monitoring eye health is important given the association between increasing myopia and the lifelong risk of myopia-associated pathology and vision impairment.5 In particular, the risk of myopic maculopathy is double for the 1–3D myope compared to the emmetrope, increasing to a 10 times greater risk for the 3–5D myope and 40 times greater risk for the 5–7D myope. While myopic maculopathy may be considered the purview of the elderly patient, the leading cause of monocular blindness in Japanese adults over 40 years is myopic macular degeneration (MMD).6 A systematic review and meta-analysis estimated that 10 million people in the world suffered visual impairment from MMD in 2015 (prevalence 0.13%), with 3.3 million suffering blindness. Given current data and projections on increasing myopia prevalence across the world, the authors predicted that by 2050, more than 55 million people (0.57% of the world’s population) could suffer vision impairment from MMD and 18.5 million (0.19%) could be blind.7
The risk of vision impairment due to myopia-associated pathology increases with longer axial length, specifically more than 26mm.5 Measuring axial length in practice should see any myope exceeding this delineator undergo closer monitoring of retinal health. While axial length and level of myopia are strongly associated – a 26mm axial length is associated with, on average, around 5D of myopia5 – refraction only explains 70% of the variation in axial length, so lower myopes can still be at risk. Since most clinicians do not measure axial length in practice, consider this information as reason to follow up closely on all myopes, and educate the young adult myope of their lifelong need for ocular health monitoring.
Providing myopia correction is likely the simplest part of the equation. Older teens and young adults may be more open and willing to wear contact lenses than children, despite evidence indicating children aged eight to 12 may be the safer wearers of soft contact lenses.8 By contrast, a case analysis indicates adults may be slightly safer orthokeratology (OK) wearers than children,9 although on the whole, the risk of microbial keratitis in either reusable soft contact lenses or OK is likely similar at around one per 1,000 wearers per year.9,10 Contact lens wear leads to the potential to offer a myopia control solution for this patient group.
Attempting myopia control must be undertaken with the caveat that there are almost no studies on the success of myopia control interventions in older teens and young adults, and no randomised controlled trials. It’s crucially important to explain to these patients that while myopia control strategies may work to reduce progression, the studies undertaken are on younger children and so results cannot be guaranteed. In considering the myopia control options of spectacle lenses, contact lenses and atropine eye drops, contact lenses are the logical first choice to both provide appealing myopia correction and the best consistent potential efficacy for myopia control.
OK enjoys the largest volume of scientific support, as it is the only intervention with multiple studies enabling meta-analysis data. That data shows that OK can slow axial elongation by around 50% over two years.11 One meta-analysis of various soft concentric dual focus and multifocal contact lens designs showed a 30–50% propensity for slowing axial elongation over one year,12 however this was published prior to longer studies on each of the following lenses being published. Hence, single studies describe the currently available soft contact lens interventions, such as the CooperVision MiSight daily disposable,13 which likely shows similar efficacy to OK over a three year study. The CooperVision centre distance multifocal with +2.50 Add,14 and Mark’ennovy Mylo15 monthly replacement lenses appear to slow axial elongation similarly over three and two year studies respectively, although slightly less than the MiSight in absolute terms. The Visioneering Technologies NaturalVue lens is also an option, although comparing the results directly to the rest is difficult due to the absence of a randomised controlled trial, as was the case for the other lenses. Clinical case series research16 shows that it appears to work well in a repeated measures study design, and as a daily disposable with availability for higher myopia, this provides another option for attempting adult myopia control.
Only OK exhibits any data on young adult myopia control in the literature – two small studies provide this indication, but neither are controlled. The first found that 12 months of OK wear in eight young adult myopes (18–29 years) stabilised axial length.17 Prior progression was not quantified for comparison and there was no other adult control group. Another study found similar results in 2016, in a case series of three adults wearing OK over three years.18
Atropine eye drops could be considered, although adult visual demands could lead to less tolerance of side effects. One research abstract measured the effect of 0.01% atropine on 12 young adult participants. The maximum change in pupil diameter and accommodation recorded was 3.5 hours and 4.75 hours after drop instillation respectively, however half of the participants experienced their most impaired accommodation function eight hours after instillation. While authors stated that these results support night-time dosing to avoid peak side effects,19 the findings also indicate some caution in ensuring tolerance of atropine in young adults. Moreover, since current compounded formulations of atropine seem to need concentrations of up to 0.05% to reach efficacy similar to contact lens options,20 it makes intrinsic sense to firstly employ an optical intervention which both corrects and has the potential to control myopia.
Spectacle lens options for myopia control – progressive addition, bifocal and peripheral defocus designs – have generally shown lower efficacy21 than OK and multifocal soft contact lens options. The Defocus Incorporated Multi-Segment (D.I.M.S) spectacle lens design, recently released in Australia and New Zealand by Hoya as MiyoSmart, has shown efficacy similar to the best performing contact lens options in a two year study.22 This could present a myopia-correction-and-control option for older teens and young adults, although visual adaptation to the lens design could perhaps render the contact lens options easier for this patient group to visually tolerate.
As discussed, any myopia control intervention for young adults is an extrapolation of the evidence – where the benefits of the myopia correction should likely be weighed equally with the potential propensity for myopia control. The sum of the above emphasises that in managing the young adult myope, it’s important to be aware that significant myopia progression can occur, and frequently does in the early-to-mid 20s. However, in contrast to children, it occurs over a few years, rather than across a single year. Around 35% of 20–25 year-old myopes will progress by 1D or more over five years, and every dioptre matters, with analysis indicating that one less dioptre of final myopia reduces the lifelong risk of myopic maculopathy by 40%.23 Even once myopia is stable, best practice management involves patient education and proactive, continual ocular health monitoring across their lifetime.
The author extends acknowledgement and thanks to optometrists Cassandra Haines, Kimberley Ngu and Connie Gan for authorship of parts of this source material, as previously published on www. myopiaprofile.com, and Dr Kate Gifford for help with manuscript preparation.
Dr Paul Gifford is a research scientist and industry innovator who graduated as an optometrist from City University, London in 1995, then worked in clinical practice for a decade before being awarded his PhD in hyperopic orthokeratology and contact lens optics in 2009 from the University of New South Wales (UNSW), Sydney. Dr Gifford’s experience includes every facet of the optometry profession, from clinical practice to academia, research and industry. He holds over 50 peer reviewed and professional publications, and has presented more than 50 conference lectures in Australia and internationally. Dr Gifford holds three professional fellowships; and has been conferred two prestigious research awards from the British Contact Lens Association, along with seven other research awards during his PhD, and two post-doctorate research grants. He holds an adjunct academic position at UNSW and consults to the contact lens industry on projects relating to product and systems design and software solutions including machine learning. He is a co-founder and director of the education platform Myopia Profile.
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- Group TC. Myopia stabilization and associated factors among participants in the Correction of Myopia Evaluation Trial (COMET). Invest Ophthalmol Vis Sci. 2013;54:7871-84.
- Scheiman M, Zhang Q, Gwiazda J, Hyman L, Harb E, Weissberg E, et al. Visual activity and its association with myopia stabilisation. Ophthalmic Physiol Opt. 2014;34(3):353-61.
- Bullimore MA, Jones LA, Moeschberger ML, Zadnik K, Payor RE. A retrospective study of myopia progression in adult contact lens wearers. Invest Ophthalmol Vis Sci. 2002;43:2110-3.
- Parssinen O, Kauppinen M, Viljanen A. The progression of myopia from its onset at age 8-12 to adulthood and the influence of heredity and external factors on myopic progression. A 23-year follow-up study. Acta Ophthalmol. 2014;92(8):730-9.
- Tideman JW, Snabel MC, Tedja MS, van Rijn GA, Wong KT, Kuijpers RW, et al. Association of Axial Length With Risk of Uncorrectable Visual Impairment for Europeans With Myopia. JAMA Ophthalmol. 2016;134(12):1355-63.
- Iwase A, Araie M, Tomidokoro A, Yamamoto T, Shimizu H, Kitazawa Y, et al. Prevalence and causes of low vision and blindness in a Japanese adult population: the Tajimi Study. Ophthalmology. 2006;113(8):1354-62.
- Fricke TR, Jong M, Naidoo KS, Sankaridurg P, Naduvilath TJ, Ho SM, et al. Global prevalence of visual impairment associated with myopic macular degeneration and temporal trends from 2000 through 2050: systematic review, meta-analysis and modelling. Br J Ophthalmol. 2018;102(7):855-62.
- Bullimore MA. The Safety of Soft Contact Lenses in Children. Optom Vis Sci. 2017;94(6):638-46.
- Bullimore MA, Sinnott LT, Jones-Jordan LA. The risk of microbial keratitis with overnight corneal reshaping lenses. Optom Vis Sci. 2013;90:937-44.
- Stapleton F, Keay L, Edwards K, Naduvilath T, Dart JKG, Brian G, et al. The Incidence of Contact Lens Related Microbial Keratitis in Australia. Ophthalmol. 2008;115:1655-62.
- Sun Y, Xu F, Zhang T, Liu M, Wang D, Chen Y, et al. Orthokeratology to control myopia progression: a metaanalysis. PLoS One. 2015;10:e0124535.
- Li SM, Kang MT, Wu SS, Meng B, Sun YY, Wei SF, et al. Studies using concentric ring bifocal and peripheral add multifocal contact lenses to slow myopia progression in school-aged children: a meta-analysis. Ophthalmic Physiol Opt. 2017;37(1):51-9.
- Chamberlain P, Peixoto-de-Matos SC, Logan NS, Ngo C, Jones D, Young G. A 3-year Randomized Clinical Trial of MiSight Lenses for Myopia Control. Optom Vis Sci. 2019;96(8):556-67.
- Walline JJ, Walker MK, Mutti DO, Jones-Jordan LA, Sinnott LT, Giannoni AG, et al. Effect of High Add Power, Medium Add Power, or Single-Vision Contact Lenses on Myopia Progression in Children: The BLINK Randomized Clinical Trial. JAMA. 2020;324(6):571-80.
- Sankaridurg P, Bakaraju RC, Naduvilath T, Chen X, Weng R, Tilia D, et al. Myopia control with novel central and peripheral plus contact lenses and extended depth of focus contact lenses: 2 year results from a randomised clinical trial. Ophthalmic Physiol Opt. 2019;39(4):294-307.
- Cooper J, O’Connor B, Watanabe R, Fuerst R, Berger S, Eisenberg N, et al. Case Series Analysis of Myopic Progression Control With a Unique Extended Depth of Focus Multifocal Contact Lens. Eye Contact Lens. 2018;44(5):16-24.
- Gifford KL, Gifford P, Hendicott PL, Schmid KL. Zone of Clear Single Binocular Vision in Myopic Orthokeratology. Eye Contact Lens. 2020;46(2):82-90.
- Gonzalez-Meijome JM, Carracedo G, Lopes-Ferreira D, Faria-Ribeiro MA, Peixoto-de-Matos SC, Queiros A. Stabilization in early adult-onset myopia with corneal refractive therapy. Cont Lens Anterior Eye. 2016;39(1):72-7.
- Kona N, Kochik S, Liu Y. Eight hour survey of 0.01% atropine induced chagnes in pupil size and accommodative function. Optom Vis Sci. 2018;95(AAO Conference Abstract):185242.
- Yam JC, Jiang Y, Tang SM, Law AKP, Chan JJ, Wong E, et al. Low-Concentration Atropine for Myopia Progression (LAMP) Study: A Randomized, Double-Blinded, Placebo-Controlled Trial of 0.05%, 0.025%, and 0.01% Atropine Eye Drops in Myopia Control. Ophthalmology. 2019;126:113-24.
- Huang J, Wen D, Wang Q, McAlinden C, Flitcroft I, Chen H, et al. Efficacy Comparison of 16 Interventions for Myopia Control in Children: A Network Meta-analysis. Ophthalmol. 2016;123(4):697-708.
- Lam CSY, Tang WC, Tse DY, Lee RPK, Chun RKM, Hasegawa K, et al. Defocus Incorporated Multiple Segments (DIMS) spectacle lenses slow myopia progression: a 2-year randomised clinical trial. Br J Ophthalmol. 2020;104:363-8.
- Bullimore MA, Brennan NA. Myopia Control: Why Each Diopter Matters. Optom Vis Sci. 2019;96(6):463-5.