Key messages
• Medications such as atropine, given as eye drops, can slow the progression of short- or near-sightedness (myopia) in children, and also reduce elongation of the eyeball due to myopia. Higher doses of atropine are most effective. We are uncertain about the effects of lower doses of atropine.
• Several treatments, including special types of lenses in eye glasses as well as contact lenses, may slow the progression of short-sightedness, but their effect is still uncertain and there is insufficient information on the risk of unwanted effects.
• It is also unclear whether the reported benefit of medications or lenses on myopia progression is maintained over the years.
What is short-sightedness?
Short-sightedness (or near-sightedness or myopia) means people struggle to see objects that are far away clearly, while objects that are near remain clear. It is very common worldwide, and affects more than half of children in China and South-East Asia. Short-sightedness may impair many aspects of life, including educational and occupational activities. Moreover, short-sighted people have longer eyes, which means that the retina is stretched. This puts the eye at greater risk of eye diseases such as glaucoma, maculopathy and retinal detachment later in life.
How is short-sightedness treated?
Although conventional eyeglasses or contact lenses are able to correct short sight, they do not slow its progression. A number of optical treatments (glasses and contact lenses) and medications are available that aim to slow the progression of short-sightedness. But they need to be given in childhood, when short-sightedness progresses most quickly. Medications such as atropine eye drops may be effective, but can cause increased sensitivity to glare and cause problems when reading, especially at higher doses. Special eyeglasses are also available, that include more than one focus power within the lens (multifocal or peripheral-plus lenses). These can also be provided as soft contact lenses. Other contact lenses, called orthokeratology, aim to temporarily change the shape of the eye surface and are worn during sleep and removed during the day. Both soft contact lenses and orthokeratology may increase the risk of infections to the eye surface
What did we want to find out?
We aimed to find out whether medications used as eye drops, and special lenses in eyeglasses or contact lenses, can slow the progression of myopia, as well as the elongation of the eyeball. We also documented the risk of unwanted effects of such interventions.
What did we do?
We searched for studies that tested medications and lenses aiming to slow progression of short-sightedness in children, compared with a control group or with other medications and lenses. The control group generally received a placebo (sham) treatment or single vision eye glasses or contact lenses.
What did we find?
• Higher doses of atropine may reduce the progression of short-sightedness, but the effect of low-dose atropine could be small and is uncertain.
• Based on short-term studies, orthokeratology is the most effective of the optical treatments in slowing elongation of the eyeball. These lenses were often difficult to tolerate, however, with more than half of children not completing the treatment in some studies.
• Other types of contact lenses, known as multifocal soft contact lenses, may also reduce the progression of short-sightedness, but, again, we remain uncertain about their beneficial effects.
• Unwanted effects associated with myopia control interventions were not consistently reported. Eye discomfort in bright light and blurred near vision were the most common treatment-related unwanted effects in studies using atropine. Lower doses of atropine appear to have fewer unwanted effects.
• Although studies that tested contact lenses did not report any serious unwanted effects, it is unclear what the true rate of unwanted effects would be for children outside a research study or when wearing contact lenses for longer periods.
What are the limitations of the evidence?
Most of the evidence came from studies conducted in ways that may have introduced errors into their results, and potential unwanted effects were not well reported. The majority of the studies followed participants up for 2 years or less and therefore there is insufficient evidence on whether incremental benefits are found over the years and whether the effects are sustained.
How up to date is the evidence?
This review is up-to-date to February 2022.
Studies mostly compared pharmacological and optical treatments to slow the progression of myopia with an inactive comparator. Effects at one year provided evidence that these interventions may slow refractive change and reduce axial elongation, although results were often heterogeneous. A smaller body of evidence is available at two or three years, and uncertainty remains about the sustained effect of these interventions. Longer-term and better-quality studies comparing myopia control interventions used alone or in combination are needed, and improved methods for monitoring and reporting adverse effects.
Myopia is a common refractive error, where elongation of the eyeball causes distant objects to appear blurred. The increasing prevalence of myopia is a growing global public health problem, in terms of rates of uncorrected refractive error and significantly, an increased risk of visual impairment due to myopia-related ocular morbidity. Since myopia is usually detected in children before 10 years of age and can progress rapidly, interventions to slow its progression need to be delivered in childhood.
To assess the comparative efficacy of optical, pharmacological and environmental interventions for slowing myopia progression in children using network meta-analysis (NMA). To generate a relative ranking of myopia control interventions according to their efficacy. To produce a brief economic commentary, summarising the economic evaluations assessing myopia control interventions in children. To maintain the currency of the evidence using a living systematic review approach.
We searched CENTRAL (which contains the Cochrane Eyes and Vision Trials Register), MEDLINE; Embase; and three trials registers. The search date was 26 February 2022.
We included randomised controlled trials (RCTs) of optical, pharmacological and environmental interventions for slowing myopia progression in children aged 18 years or younger. Critical outcomes were progression of myopia (defined as the difference in the change in spherical equivalent refraction (SER, dioptres (D)) and axial length (mm) in the intervention and control groups at one year or longer) and difference in the change in SER and axial length following cessation of treatment ('rebound').
We followed standard Cochrane methods. We assessed bias using RoB 2 for parallel RCTs. We rated the certainty of evidence using the GRADE approach for the outcomes: change in SER and axial length at one and two years. Most comparisons were with inactive controls.
We included 64 studies that randomised 11,617 children, aged 4 to 18 years. Studies were mostly conducted in China or other Asian countries (39 studies, 60.9%) and North America (13 studies, 20.3%). Fifty-seven studies (89%) compared myopia control interventions (multifocal spectacles, peripheral plus spectacles (PPSL), undercorrected single vision spectacles (SVLs), multifocal soft contact lenses (MFSCL), orthokeratology, rigid gas-permeable contact lenses (RGP); or pharmacological interventions (including high- (HDA), moderate- (MDA) and low-dose (LDA) atropine, pirenzipine or 7-methylxanthine) against an inactive control. Study duration was 12 to 36 months. The overall certainty of the evidence ranged from very low to moderate.
Since the networks in the NMA were poorly connected, most estimates versus control were as, or more, imprecise than the corresponding direct estimates. Consequently, we mostly report estimates based on direct (pairwise) comparisons below.
At one year, in 38 studies (6525 participants analysed), the median change in SER for controls was −0.65 D. The following interventions may reduce SER progression compared to controls: HDA (mean difference (MD) 0.90 D, 95% confidence interval (CI) 0.62 to 1.18), MDA (MD 0.65 D, 95% CI 0.27 to 1.03), LDA (MD 0.38 D, 95% CI 0.10 to 0.66), pirenzipine (MD 0.32 D, 95% CI 0.15 to 0.49), MFSCL (MD 0.26 D, 95% CI 0.17 to 0.35), PPSLs (MD 0.51 D, 95% CI 0.19 to 0.82), and multifocal spectacles (MD 0.14 D, 95% CI 0.08 to 0.21). By contrast, there was little or no evidence that RGP (MD 0.02 D, 95% CI −0.05 to 0.10), 7-methylxanthine (MD 0.07 D, 95% CI −0.09 to 0.24) or undercorrected SVLs (MD −0.15 D, 95% CI −0.29 to 0.00) reduce progression.
At two years, in 26 studies (4949 participants), the median change in SER for controls was −1.02 D. The following interventions may reduce SER progression compared to controls: HDA (MD 1.26 D, 95% CI 1.17 to 1.36), MDA (MD 0.45 D, 95% CI 0.08 to 0.83), LDA (MD 0.24 D, 95% CI 0.17 to 0.31), pirenzipine (MD 0.41 D, 95% CI 0.13 to 0.69), MFSCL (MD 0.30 D, 95% CI 0.19 to 0.41), and multifocal spectacles (MD 0.19 D, 95% CI 0.08 to 0.30). PPSLs (MD 0.34 D, 95% CI −0.08 to 0.76) may also reduce progression, but the results were inconsistent. For RGP, one study found a benefit and another found no difference with control. We found no difference in SER change for undercorrected SVLs (MD 0.02 D, 95% CI −0.05 to 0.09).
At one year, in 36 studies (6263 participants), the median change in axial length for controls was 0.31 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD −0.33 mm, 95% CI −0.35 to 0.30), MDA (MD −0.28 mm, 95% CI −0.38 to −0.17), LDA (MD −0.13 mm, 95% CI −0.21 to −0.05), orthokeratology (MD −0.19 mm, 95% CI −0.23 to −0.15), MFSCL (MD −0.11 mm, 95% CI −0.13 to −0.09), pirenzipine (MD −0.10 mm, 95% CI −0.18 to −0.02), PPSLs (MD −0.13 mm, 95% CI −0.24 to −0.03), and multifocal spectacles (MD −0.06 mm, 95% CI −0.09 to −0.04). We found little or no evidence that RGP (MD 0.02 mm, 95% CI −0.05 to 0.10), 7-methylxanthine (MD 0.03 mm, 95% CI −0.10 to 0.03) or undercorrected SVLs (MD 0.05 mm, 95% CI −0.01 to 0.11) reduce axial length.
At two years, in 21 studies (4169 participants), the median change in axial length for controls was 0.56 mm. The following interventions may reduce axial elongation compared to controls: HDA (MD −0.47mm, 95% CI −0.61 to −0.34), MDA (MD −0.33 mm, 95% CI −0.46 to −0.20), orthokeratology (MD −0.28 mm, (95% CI −0.38 to −0.19), LDA (MD −0.16 mm, 95% CI −0.20 to −0.12), MFSCL (MD −0.15 mm, 95% CI −0.19 to −0.12), and multifocal spectacles (MD −0.07 mm, 95% CI −0.12 to −0.03). PPSL may reduce progression (MD −0.20 mm, 95% CI −0.45 to 0.05) but results were inconsistent. We found little or no evidence that undercorrected SVLs (MD -0.01 mm, 95% CI −0.06 to 0.03) or RGP (MD 0.03 mm, 95% CI −0.05 to 0.12) reduce axial length.
There was inconclusive evidence on whether treatment cessation increases myopia progression. Adverse events and treatment adherence were not consistently reported, and only one study reported quality of life.
No studies reported environmental interventions reporting progression in children with myopia, and no economic evaluations assessed interventions for myopia control in children.