Cochrane Eyes and Vision Editor and Optometrist, John Lawrenson blogs about the latest Cochrane evidenceCochrane Reviews are systematic reviews. In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. on interventions for controlling myopia in children and asks ‘What is the most effective treatmentSomething done with the aim of improving health or relieving suffering. For example, medicines, surgery, psychological and physical therapies, diet and exercise changes.?’
Myopia, a 21st century global public health problem
With myopia (near or shortsightedness) predicted to affect 50% of the world populationThe group of people being studied. Populations may be defined by any characteristics e.g. where they live, age group, certain diseases. by 2050, the condition is rapidly becoming a global public health concern. Myopia, which causes distant objects to become blurred, is already reaching epidemic proportions in certain parts of East and South East Asia. For example, in urban areas of South East Asia, over 90% of children are myopic by the time they complete their high school education, an approximate 23% increase over the last decade. Although often regarded as simply a minor inconvenience, high degrees of myopia are associated with sight-threatening eye problems such as myopic degeneration of the retina and retinal detachment.
Interventions to slow myopia
At birth, newborns are usually longsighted (hyperopic), which then slowly declines to the point that by five to seven years of age, children typically have either normal eyesight or a low degree of hyperopia. Myopia is uncommon in children under six even in East Asia, however in high-risk populations the number with myopia increases dramatically after this age, possibly linked to the intensity of the educational system. In recent years, there has been a considerable amount of interest in the development and testing of interventions to slow the rateThe speed or frequency of occurrence of an event, usually expressed with respect to time. For instance, a mortality rate might be the number of deaths per year, per 100,000 people. of progression of myopia. These interventions generally use one of three approaches:
- Optical treatments that use multifocal glasses or contact lenses to achieve a more clearly focussed retinal image
- Specially designed rigid contact lenses (orthokeratology) that are usually worn at night to reshape the cornea at the front of the eye to reduce myopia
- Pharmacological interventions that involve the use of anti-muscarinic eye drops, which act on the eyes focussing system and lead to biochemical changes that slow the rate of eye growth.
The latest evidence
A recently updated Cochrane reviewCochrane Reviews are systematic reviews. In systematic reviews we search for and summarize studies that answer a specific research question (e.g. is paracetamol effective and safe for treating back pain?). The studies are identified, assessed, and summarized by using a systematic and predefined approach. They inform recommendations for healthcare and research. included 41 studies with 6772 children, comparing several optical and pharmacological interventions to slow progression of myopia. The review provided moderate certainty evidence that antimuscarinic eye drops, such as atropine were probably an effective treatment for myopia control. However, some children experienced side effects related to the drops, such as focussing difficulties, sensitivityA measure of a screening or diagnostic test’s ability to correctly detect people who have the disease. to light and eye discomfort. In one of the largest studies approximately 15% of children stopped therapy due to side effects. Studies investigating interventions such as multifocal spectacles or specialised contact lenses, showed that that these may have a small benefit in slowing myopia.
Where does this leave us?
Atropine eye drops currently seem to be the most effective treatment for myopia control, although there is still uncertainty regarding the optimal dose and duration of therapy. Although lower doses may reduce side effects, this may be associated with a decrease in their effectivenessThe ability of an intervention (for example a drug, surgery, or exercise) to produce a desired effect, such as reduce symptoms.. Furthermore, the benefit of using antimuscarinic eye drops in combination with spectacle or contact lens interventions needs further clarification.
Advice to parents of children at risk of developing myopia
An increasing number of eye care practitioners are offering a variety of pharmacological and optical interventions to slow the rate of myopia progression. It is therefore important that parents are provided with the most current and relevant evidence on the likely success of these treatments. This updated Cochrane review is therefore very timely. The most effective interventionA treatment, procedure or programme of health care that has the potential to change the course of events of a healthcare condition. Examples include a drug, surgery, exercise or counselling. in the reported studies was atropine eye drops; however, the concentration of atropine used (0.5%, 1%) was higher than the lower dose (0.01%) currently being offered by most practitioners. Furthermore, the studies were conducted in East Asia and it is unclear whether the reported effectiveness would extend to other ethnic groups.
Take-home points
Join in the conversation on Twitter with @jglawrenson @CochraneUK @CochraneEyes or leave a comment on the blog. Please note, we will not publish comments that link to commercial sites or appear to endorse commercial products.
John Lawrenson has nothing to disclose.
