AS MORE EYECARE practitioners are embracing proactive treatment strategies for patients who have progressive myopia, some are turning their attention toward delaying or preventing myopia. Is myopia prevention the next frontier in myopia management?
WHY CONSIDER PREVENTION?
The rate of eye growth is strongly correlated with age, and even emmetropic children experience more rapid eye growth during earlier years (Zadnik et al, 2004; Tideman et al, 2020). Thus, it should not be surprising that myopia diagnosis at a younger age is a key predictor for the risk of future high myopia. Approximately 50% of children diagnosed at 7 to 8 years old progress to high myopia, compared with only about 5% of those diagnosed at age 12 (Hu et al, 2020; Chua et al, 2016).
It has been shown that delaying myopia onset by a single year may result in significantly less final myopia (0.75D or more) for some patients (Bullimore and Brennan, 2020). Since even a small reduction in final refractive error may yield a significantly decreased risk for myopic comorbidities (Bullimore and Brennan, 2016), delaying myopia onset is certainly an idea that eyecare providers should consider.
WHAT OPTIONS ARE THERE?
Optimizing time spent outdoors has shown modest benefits for reducing myopia incidence in several studies (Xiong et al, 2017). While the mechanism is not understood, it may be related to exposure to bright, broad-spectrum light or to the reduced amount of time spent focusing on near objects.
A meta-analysis found that spending fewer than 13 hours per week outdoors (just under two hours per day) was associated with the highest risk for myopia incidence in non-myopic children (Xiong et al, 2017). Increasing outdoor time by one hour per day was estimated to result in a nearly 50% reduction in risk for becoming myopic (Xiong et al, 2017). A simple recommendation for parents and children is to program at least two hours per day in an outdoor environment.
Several studies have demonstrated that low-dose atropine (0.01% to 0.05%) may reduce the risk for childhood myopia incidence (Lee et al, 2024). Across four studies involving pre-myopic children from ages 4 to 12, a meta-analysis on the subject found that low-dose atropine therapy resulted in a significantly lower myopia incidence (risk ratio 0.62) versus controls (Lee et al, 2024). More studies are needed to evaluate factors such as the impact of atropine concentration on effectiveness and potential rebound eye growth at cessation, but nevertheless, atropine therapy may a feasible option for pre-myopes.
Ultimately, practitioners may find that many interventions that work for slowing myopia progression demonstrate effectiveness for delaying the onset of myopia. One obstacle for optical interventions such as soft contact lenses or orthokeratology is that most pre-myopic children do not require corrective lenses for vision improvement; thus, it may be more difficult to employ these solutions for non-myopes.
Although there are no solutions available that can completely prevent myopia, a growing body of evidence suggests that delaying myopia onset (particularly in younger children) is not only possible, but potentially highly beneficial.
REFERENCES
1. Zadnik K, Mutti DO, Mitchell GL, Jones LA, Burr D, Moeschberger ML. Normal eye growth in emmetropic schoolchildren. Optom Vis Sci. 2004 Nov;81:819-828.
2. Tideman W, Enthoven C, Jaddoe V, Polling JR, Klaver C. Axial length growth from 6 to 13 years of age and risk of myopia at age 13: The Generation R study. Invest Ophthalmol Vis Sci. 2020 Jun; 61:852.
3. Hu Y, Ding X, Guo X Chen Y, Zhang J, He M. Association of Age at Myopia Onset With Risk of High Myopia in Adulthood in a 12-Year Follow-up of a Chinese Cohort. JAMA Ophthalmol. 2020 Nov 1;138:1129-1134.
4. Chua SY, Sabanayagam C, et al. Age of onset of myopia predicts risk of high myopia in later childhood in myopic Singapore children. Ophthalmic Physiol Opt. 2016 Jul;36:388-394.
5. Bullimore MA, Brennan NA. Final Level of Myopia versus Age of Onset: Effect of Race and Age at Final Refraction. Invest Ophthalmol Vis Sci. 2022 Jun;63:4244.
6. Bullimore MA, Brennan NA. Myopia Control: Why Each Diopter Matters. Optom Vis Sci. 2016 June;96:463-465.
7. Xiong S, Sankaridurg P, Naduvilath T, et al. Time spent in outdoor activities in relation to myopia prevention and control: a meta-analysis and systematic review. Acta Ophthalmol. 2017 Sep;95:551-566.
8. Lee SH, Tseng B-Y, Wang J-H, Chiu C-J. Efficacy and Safety of Low-Dose Atropine on Myopia Prevention in Premyopic Children: Systematic Review and Meta-Analysis. J Clin Med. 2024; 13:1506.
