Intervention & Treatments
Types of intervention
Research in the last 50 years has helped understand many influences on myopia progression and now new interventions.
We have a large amount of data linking less natural light to faster myopia progression in children. We advocate that exposure to natural light reduces the rate of myopia progression. Protecting your child from UV harm is still important with hats, sunscreen, and sunglasses. The lux of light required to benefit myopia progression cannot be replicated indoors. The recommendations are now that at least 2 hours a day, seven days a week can substantially impact the rate of myopia progression. Exposure to the intensity of outdoor light also benefits children before they are myopia (the pre-myope).
Near work of all types and education has been linked to greater myopia progression. It is helpful to reduce near work, including changing how we view technology. It is now considered an independent risk factor for fast myopia progression in children.
Low dose Atropine
There are over 15 years of experience with clinical trials using low-dose atropine to reduce myopia progression in children. Atropine has a dose-dependent response. The higher the dose, the greater the effect on myopia progression and the greater the side effects. Side effects include near blur and glare from the pupil-dilating effect of atropine. Until recently, all low-dose atropine was only available at a compound pharmacy. Eikance 0.01% (Atropine 0.01%) is now available with TGA approval as of February 2022 in Australia. Other doses, including atropine 0.05% (with evidence from the LAMP studies) available from compound pharmacies.
Glasses and Contact lenses
Research has been keen to find a lens design that can slow down the elongation of the eye causing childhood myopia progression. There are exciting developments with novel glasses that are recently available to retard myopia progression.
Soft contact lens design has also been developed aimed at retarding myopia progression. All contact lenses risk microbial keratitis (an infection on the window of the eye, the cornea), which can be sight-threatening. This risk can be reduced by the use of disposable contact lenses, which negate the need to clean and reuse the lens again.
There are also rigid contact lenses called orthokeratology (Ortho-K or OK lenses) designed to wear overnight and often negate the use of glasses during the day. They require cleaning for reuse. The side effect profile also includes the risk of microbial keratitis.
Peripheral defocus lenses are now available for spectacle dispensing in Australia. These include DIMS design (MiyoSmart HOYA), HAL design (Stellest Essilor), Competing defocus (MyoCare Zeiss) and Peripheral progressive defocus (Mycon Rodenstock). All these designs are based on the knowledge that the periphery of the eye is the signal for eye growth. A signal in front of the retina (instead of behind the retina with single vision or no glasses) causes the eye to reduce its elongation rate.
Low-level red-light therapy
Recent publications include the use of low-level red light (650 nm) prescribed for 3 minutes twice a day (4 hours apart) for 5 days a week may reduce progression substantially. This therapy has recently been TGA-approved in Australia for progressive myopia in children.
Blue light therapy
Blue light dispensed via a VR headset is actively being studied overseas.
Measurement of myopia progression
Traditionally the amount of refractive error (focus problem) of the eye has been calculated by the power in dioptres (D). This means that as the eye progresses in myopic, you need a minus lens of a certain power to put the image in focus on the retina inside the eye. The longer the eye, the greater minus dioptres needed. Therefore, myopia progression means the minus glasses get greater in number as the eye grows.
A more accurate method of myopia progression is the actual amount the eye is growing and measuring the axial length in millimetres. Myopia progression can now be analysed by micrometre accuracy by measuring the eye with non-contact techniques. These measurements can now be compared to growth curves from around the world.