What is myopia?
Myopia (nearsightedness) is an ocular disease in which the length of the eye is longer than the average eye. These patients can see better at near compared to far away. Prescription glasses or contact lenses are used to move the optical image to the retina in the back of the eye so that the image is focused and the patient can see clearly.
Why is it important to control myopia?
It is commonly understood that myopia prevalence is growing globally. By 2050, it is predicted that half of the world’s population - five billion people - will be myopic, with nearly one billion at risk of myopia related ocular pathology. High myopia is strongly linked to higher risk of cataract, retinal detachment and myopic maculopathy, and increasing rates of vision impairment and blindness due to the latter are already evident in Asian countries. The World Health Organization now recognizes the public health issue of myopia.
Myopia (nearsightedness) is an ocular disease in which the length of the eye is longer than the average eye. These patients can see better at near compared to far away. Prescription glasses or contact lenses are used to move the optical image to the retina in the back of the eye so that the image is focused and the patient can see clearly.
Why is it important to control myopia?
It is commonly understood that myopia prevalence is growing globally. By 2050, it is predicted that half of the world’s population - five billion people - will be myopic, with nearly one billion at risk of myopia related ocular pathology. High myopia is strongly linked to higher risk of cataract, retinal detachment and myopic maculopathy, and increasing rates of vision impairment and blindness due to the latter are already evident in Asian countries. The World Health Organization now recognizes the public health issue of myopia.
What treatment options are available to control myopia?
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Orthokeratology
Ortho-K lenses are FDA approved contacts that reshape the cornea overnight while asleep, allowing the patient with low to moderate myopia to see without glasses or contacts during the day.
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Low dose atropine
1% atropine eye drops are approved by the FDA for the treatment of amblyopia and strabismus, however 0.05% and 0.02% atropine eye drops for myopia retardation is still considered off-label use. In a 5 year trial, low dose atropine has been shown to slow myopia progression by 54%. Low dose atropine has been shown to be effective in myopia control without the negative effects higher doses have on the pupil and accommodation.
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Soft contact lenses
These contact lenses are used during the day and are used to slow the progression of myopia with the same effectiveness as orthokeratology.
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Bifocal or progressive addition lenses for spectacles
Executive bifocal spectacles, with a +1.50 D addition, slowed the rate of progression of myopia by 39-51% and axial elongation by 34% in Canadian Chinese children over a three year period.
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Other risk factors relevant to myopia:
- Age – patients 5 to 9 years old with myopia will progress at a faster rate than older patients
- Ethnicity – myopia prevalence in east Asia is 80-97%
- Family history of myopia – a child with 1 myopic parent is 3x more likely to become myopic; with both parents is 6x more likely to become myopic
- Spectacle prescription and current progression
- Less than 90 minutes spent outdoors daily can increase risk of developing myopia
- More than 2.5 hours spent on near work daily can increase risk of developing myopia
On average, the most effective myopia control options have the following average levels of control:
- Ortho-K contact lenses: 41%
- Soft multifocal type contact lenses: 40%
- Low-dose atropine: 50%
Important take home messages:
- Delaying or preventing myopia can reduce the risk of high myopia
- Myopia increases future risk of eye diseases that can permanently affect vision
- Simple strategies can be used to delay the onset of myopia
For the prevention of myopia onset, general recommendations include:
- Increased outdoor time
Upwards of 90 minutes outdoor time per day is recommended.
- Frequent breaks from near work
Regular breaks, which involve distance tasks, are recommended when children are engaged in near tasks.