What is Myopia?
Myopia (or near-sightedness) is a very common eye condition that tends to begin in childhood. With myopia, the eyeball is longer than normal from front to back and/or the cornea (the clear window at the front of the eye) is too steeply curved. This leads to light being focussed in front of the retina and objects that are far away to look blurry.
What does my child see?
A child with myopia tends to see blur in the distance. This can make distance tasks more difficult, including seeing the board at school, playing sports and watching TV.
Why does my child have myopia?
Our current understanding is that there are multiple factors that can influence one’s chances of being myopic. Myopia is largely impacted by your genetics, environmental and behavioural factors such as reduced time outdoors and increased near work. Family history of myopia can also increase the likelihood of developing myopia. See the infographic on the assessment of risk by the Brian Holdend Vision Institute below.
Does myopia get worse and why is it a problem?
When children develop myopia, the myopia tends to increase over time until their mid to late teens. This increase in myopia can eventually become high myopia, which is when the myopia reaches a prescription of -5.00 D or worse. When the myopia reaches this level, the risk of developing potentially sight-threatening complications increases exponentially. The sight-threatening complications include but are not limited to:
- Retinal detachment
Where the retina detaches from the eyeball causing vision loss.
- Myopic macular degeneration
A degeneration of the macular area (the area of the eye responsible for sharp vision).
A degeneration of the optic nerve which is responsible for transmitting signals from the eye to the brain.
Where the natural lens in the eye responsible for focussing the image becomes cloudy.
It’s important to note that these sight threatening complications generally occur later in life and fortunately can often be treated. However, the best treatment is prevention!
What can be done about it?
Myopia control in a proactive approach to treating myopia progression, it allows us to slow down the rate of change which would occur naturally without any intervention. Instead of just prescribing standard glasses or contacts lenses that merely bring vision into focus; we can now alter the trajectory of the growing eye.
It is very important to understand that myopia control slows the rate of increasing myopia but does not stop progression. Children will still be myopic and will still progress, meaning the power of their prescription will still increase as they get older. However the aim is to minimize this increase until they achieve stable vision, which for most people is when they enter their late teens, early twenties. Myopia control therefor is a long term commitment because once it is initiated; it is most effective if it is not discontinued until this time. Additionally, it is also most effective the earlier therapy is initiated.
As an example, an 8-year-old with a -1.00D prescription may progress by -0.50D every year until they are 18 years old. So at the age of 18 they have a final prescription of -6.00D. If we are able to achieve a 50% reduction in progression that same 18 year old may only end up with a final prescription of -3.50D.
At first that may not seem significant, but patients with higher levels of myopia can lead to a greater risk of vision threatening eye conditions and we can significantly lessen the distance blurriness effect of myopia.
How does Myopia Control work?
There are a variety of different treatment protocols with varying levels of effectiveness. Additionally, some children may not be a candidate for all available treatments. Therefore, a Myopia Control Assessment is the first recommended step before you and your optometrist decide on a treatment course. Talk to your optometrist for more details. Myopia control treatments can include:
1. Spectacle Therapy – Glasses
Glasses with speciality designed optics can be used for myopia control. One example is the MiYOSMART lens by Hoya with D.I.M.S. (Defocus Incorporated Multiple Segments) technology. In randomized clinical trials, patients who wore these lenses had myopia progression reduced by average of 60%. The lens is comprised of hundreds of small segments, each providing vision correction AND myopic defocus. The best part is that these segments are almost invisible to the naked eye making them appear just as any other standard lens. Visit https://www.hoyavision.com/vision-products/miyosmart/ to read the full studies.
Spectacle therapy is a great option for any child at any age who can wear glasses. They are simple to use and can fit a wide range of patient prescriptions.
2. Soft Contact Lenses
These are soft contact lenses, much like any other traditional soft contact lens, but are used for myopia control.
One such example is the MiSight contact lens. The MiSight contact lens is a soft daily disposable contact lens with specially designed optics that has been shown to reduce the rate of change of a child’s myopia by up to 59%. The lenses provides good focus centrally to allow clear vision while the peripheral area of the contact intentionally creates myopic defocus outside of the macular area to provide the therapeutic effect of myopia control. These lenses are only available to optometrist who are trained to fit these lenses and practice myopia control. If your child has never worn contacts before, our team can book a contact lens training session after your initial visit.
Some hurdles to soft multifocal lenses are training younger children to insert and remove lenses and not all prescriptions can be corrected with these lenses. For more information visit https://coopervision.ca/practitioner/our-products/misight/misight-1-day
Ortho-K therapy involves changing the curvature of the cornea by temporarily moulding its shape using a ridged gas permeable contact lens. By changing the curvature of the cornea, light is refocused onto the retina. This results in clear vision centrally and intentionally creates a ring of myopic defocus on the peripheral retina which provides the therapeutic effect of myopia control. Multiple studies have found a decrease in myopia progression ranging from 36%-80% with most showing around 51%. These lenses are worn at night and then removed in the morning (similar to a retainer for your teeth). This provides clear vision during the day without glasses or contacts. The effects are temporary, so the lenses must be worn every night for them to work during the day.
Some hurdles to Ortho-K therapy are that the initial fitting process of these lenses and training on how to insert and remove these lenses. Fittings can take multiple appointments because they are customized to each individual. A Myopia Control Assessment is necessary to determine if you are a good candidate for these lenses.
4. Atropine Therapy
Atropine is a medication used at a diluted concentration as an eyedrop daily. It is classified as non-selective anti-muscarinic agent. Atropine has been used and studied for many years as a myopia control agent, with an effectiveness of around 50%. Although the exact mechanism of atropine is unknown, it has generally been well tolerated by patients. Used at a diluted concentration, atropine may have a small effect on pupil dilation and in only some children, reduces the ability to focus on things up close. At your Myopia Control Assessment, your optometrist will be able to determine is Atropine is appropriate.
Atropine drops are dispensed at compounding pharmacies and require a prescription. It is easy to use and can be used in younger patients who are unable to insert or remove contacts or wear glasses. Atropine can be prescribed in conjunction with the other optical methods described above. Studies on the combined myopia control effects of multiple treatment modalities are ongoing.
Despite its long history and safety profile, Atropine Therapy it is not technically FDA or Healthy Canada approved for slowing the progression of myopia. So, its use is considered “off label”. Off-label use is legal and does not mean that the treatment being used is inappropriate, especially if its use is based on firm scientific evidence.
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