Approximately half of the world’s population, including children, live in towns and cities; by 2050, nearly 70% will live in urban areas . The urban landscape dominated by concentrated areas of high-rise, high-density buildings with proximity to services and industries is not only powering the economic engine of nations but transforming the way our children see the world.
The ‘average’ child of this century lives in a high-rise apartment complex, is transported to most activities (including school) and spends ever-increasing time indoors watching television or playing on tablets or smartphones. Alternatively, they are likely to dwell in the sprawling, ill-planned, cramped spaces in marginalised communities on city fringes. Either way, outdoor time is limited. This localised and restricted environment confers unique challenges with respect to eye health for today’s young.
The onslaught of Myopia
In 2010, just over 28% of the world’s population were affected by Myopia (short-sightedness). This is predicted to rise to 34% by 2020 and nearly 50% by 2050 . In some Asian countries, 70% of those 17 or above are Myopic , as are 97% of 19-year-old male army conscripts in South Korea . Myopia commonly onsets in childhood and is due to a mismatch between the eyeball length and its optical power, resulting in light focussing in front of the retina and thus causing blurred distance vision. Myopia is commonly corrected using spectacles or contact lenses; however, since the underlying mechanism of increasing eyeball length is not addressed, the condition commonly progresses until young adulthood and necessitates regular eye examinations to maintain adequate vision. Additionally, there is a more sinister side to Myopia. High levels (-5.00D or worse) increase the risk of sight-threatening conditions including retinal detachment, Cataract and Glaucoma. In addition, highly Myopic eyes are at risk of Myopic Macular Degeneration, a condition fast-emerging as a leading cause of blindness in Asia and other parts of the world.
Myopia commonly onsets in young, school-age children and progresses into adulthood.
High Myopia increases risk of developing sight-threatening conditions such as Myopic Macular Degeneration, Cataract
Managing the burden requires solutions to control onset, progression and healthcare services.
Efforts are underway to find strategies to prevent onset and progression of Myopia. Optical, pharmaceutical and environmental strategies show efficacy.
Highly Myopic eyes are at risk of Myopic Macular Degeneration, a condition fast-emerging as a leading cause of blindness in Asia and other parts of the world
What can be done?
Already, the burden of Myopia is substantial, affecting individuals (eg costs associated with corrective devices, specialist services, risk of vision impairment in adult life) and society (eg burden of uncorrected refractive error and eye care services). If left to rise unfettered, the burden will increase many-fold. Hopefully, research will aid in providing solutions to delay/prevent Myopia onset, or control progression in an already Myopic eye.
In addition to genetics, eye growth is regulated by visual feedback (environment). For example, Myopia is far more prevalent in urban populations. In animal models, eye growth can be modulated using optical blur. More excitingly, evidence indicates we can control the onset of Myopia. Increased outdoor time proved protective against Myopia onset with clinical trials from Taiwan and China indicating 40 to 80 minutes of additional outdoor time during the day in primary school children reduced Myopia incidence by 23% to 50% . In those already Myopic, select optical and pharmaceutical interventions reduced Myopia progression. Optical approaches that reduced accommodative lag of eye, reduced defocus at peripheral retina or induced Myopic defocus across the retina were successful in reducing Myopia progression by 30% to 40%.
Estimated global prevalence of Myopia – 2000 to 2050
20.2% Low to Moderate Myopia (1243m)
2.7% High Myopia (163m)
24.3% Low to Moderate Myopia (1673m)
4.0% High Myopia (277m)
28.7% Low to Moderate Myopia (2221m)
5.2% High Myopia (399m)
33.8% Low to Moderate Myopia (2844m)
6.1% High Myopia (517m)
37.5% Low to Moderate Myopia (3393m)
7.7% High Myopia (696m)
40% Low to Moderate Myopia (3820m)
9.8% High Myopia (938m)
How can Myopia be controlled?
Optical devices incorporating these strategies include executive bifocals, specially designed multifocal contact lenses and orthokeratology. Pharmaceuticals such as low-dose atropine and 7-methylxanthine show promise. While longer-term efficacy and Myopia-rebound upon discontinuation of these agents require further investigation, evidence to date implies good potential for these treatments to limit the damage and burden of higher-magnitude Myopia by reducing its incidence.
In summary, there are significant health and economic implications from the rising prevalence of Myopia. Managing the Myopia burden requires a co-ordinated effort in determining solutions to control onset and progression, and services to manage associated healthcare implications.
Myopia: at a glance
Updated on 6th Oct 2016