A global epidemic
The prevalence of myopia in young people is increasing at an alarming rate worldwide, bringing with it a host of health risks and related costs.
In the United States, myopia has doubled in the space of 30 years.1 A UK study found that nearly 50% of university students were myopic.2 In Taiwan, research shows an increase of almost 65% over the past 50 years.3 Worldwide, the prevalence of myopia is expected to increase from 2 billion in 2010 to 5 billion in 2050.4
The toll of myopia
The spread of myopia causes substantial costs to the individual and society. Compared to emmetropes, patients with even 1D of myopia face an increased lifetime risk of developing glaucoma, posterior subcapsular cataracts, retinal detachment and macular degeneration. Patients whose myopia progresses into the 5–6D range have 40 times the risk of suffering from macular degeneration.5
Options for prevention and correction
Eye care professionals are in a unique position to help prevent and control the myopia epidemic.
- Behavioural change
The chances of a child becoming myopic are reduced by approximately 30% if the child spends more than 14 daytime hours a week outdoors.6 Parents should be urged to encourage children to engage in outdoor activities as a preventative measure.
- Pharmaceutical treatment
Atropine (not yet commercially available in all countries) has been shown to significantly control myopia progression when administered at 0.01%. But the drug has a high incidence of side effects, making it clinically unpopular.7
- Spectacle lenses
In terms of control, evidence suggests that for progressing myopes with esophoria and accommodative lag >1D, spectacles with bifocal or progressive lenses can reduce the progression of myopia by 38–47%.8 However, children who wear spectacles are more likely to be bullied at a time when compliance is most crucial.9
- Contact lens control
Several promising approaches to controlling myopia with contact lenses are currently being explored. One is the use of orthokeratology (ortho-k) lenses. According to meta-analysis, this can slow axial elongation in progressing myopes by an average of 45%.10
Soft multifocal lenses have been shown to significantly slow the progression of myopia.11 Another option, not yet widely commercially available, is a soft daily disposable lens with a dual-focus, concentric design that showed a 50% reduction in axial elongation over two 10-month periods.12
Of course, wearing contact lenses can pose challenges for paediatric patients, and each youngster’s ability to maintain proper hygiene and compliance habits must be thoughtfully assessed.
Nonetheless, the continuing refinement of these and other contact lens-based methods of myopia control is highly encouraging. It is likely they will have a significant impact on everyday practice, as efforts to control the rapid increase in myopia are stepped up worldwide.
1 Vitale S, Sperduto RD, Ferris FL 3rd. Increased prevalence of myopia in the United States between 1971-1972 and 1999-2004. Arch Ophthalmol. 2009;127(12):1632-1639.
2 Logan NS, Davies LN, Mallen EA, Gilmartin B. Ametropia and ocular biometry in a U.K. university student population. Optom Vis Sci. 2005;82(4):261-266.
3 Guo YH, Lin HY, Lin LL, Cheng CY. Self-reported myopia in Taiwan: 2005 Taiwan National Health Interview Survey. Eye (Lond). 2012;26(5):684-689.
4 Flitcroft, DI. The complex interactions of retinal, optical and environmental factors in myopia aetiology. Prog Retin Eye Res. 2012;31(6):622-660.
5 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(5):1036-1042.
6 Rose KA, Morgan IG, Ip J, et al. Outdoor activity reduces the prevalence of myopia in children. Ophthalmology. 2008;115(8):1279-1285.
7 Chia A, Lu QS, Tan D. Five-year clinical trial on atropine for the treatment of myopia 2: myopia control with atropine 0.01% eyedrops. Ophthalmology. 2016;123(2):391-399.
8 Yang Z, Lan W, Ge J, et al. The effectiveness of progressive addition lenses on the progression of myopia in Chinese children. Ophthal Physiol Opt. 2009;29:41-48.
9 Horwood J, Waylen A, Herrick D, et al. Common visual defects and peer victimization in children. Invest Ophthalmol Vis Sci. 2005;46:1177-1181.
10 Walline JJ, Greiner KL, McVey ME, Jones-Jordan LA. Multifocal contact lens myopia control. Optom Vis Sci. 2013;90(11):1207-1214.
11 Sun Y, Xu F, Zhang T, et al. Orthokeratology to control myopia progression: a meta-analysis. PLoS One. 2015;10(4):e0124535.
12 Anstice NS, Phillips JR. Effect of dual-focus soft contact lens wear on axial myopia progression in children. Ophthalmology. 2011;118(6):1152-1161.