Child Myopia
Introduction
All parents approaching EndMyopia for their children, come with a sense of urgency. Please understand this is not a good approach. You need to be calm and rational in order to make good choices for your child. Remember myopia is NOT a medical condition, it is a refractive state. If your child had good vision before, they should be able to have it again. If your child does have a medical condition there might be limitations to how much this method will help, however the practices are worthwhile applications for their future vision just the same. Ideally, a myopic adult would start with EndMyopia then help a child. It is very important that an adult who fully understands the method and what vision improvement requires works with the child in question.
Please Note
It might be helpful to consider that myopia control and reversal is less like potty training (go hard for a few weeks and it's typically done with) and more like getting them to pick up after themselves (every parent knows this is a long haul lesson). Small changes over time will be a good approach.
Getting Started
Most parents new to the method have the first instinct to take away their child's correction and take away most of, if not all of, their favorite close-up activities.
Let's start with the desire to take away correction. Don't.
If your child was just told they need glasses and they have never worn them before by all means hold off on introducing correction, you might even find with new habits they won't need correction, as long as you are actively working on their vision, it is not harmful (or negligent) to not rush into correction. But instead, take some time to assess your child's vision for yourself, track trends in their vision, and introduce better vision habits; and only then introduce appropriate correction if still needed.
But, if a child is already wearing correction; they can't just stop. They need to learn to wear the correction only when needed and should never wear their full correction for near work. If their correction is stronger than -2 they will likely require differentials for near work. Ideally it is best to provide the correction for a greater distance than to have your child looking at things closer in order to eliminate that need for correction; because the closer they are to the object of focus the more strain there is on the eye. Always the goal should be to maximize their distance when in a situation of static viewing; such as reading, playing video games and computer work. The worst danger zone is under 50cms, as you can quickly surmise this includes basically everything within arms' reach for children.
In actual application especially in school it might be difficult to introduce differentials, if your child is content to remove their glasses and is confident they can see well enough doing so for near work, this is most likely easier than having them switch throughout the school day. Remind them to be mindful of switching focus often, to prevent ciliary spasm. For those who cannot remove their correction but are still unlikely to switch correction in school it is even more important to have those good habits as well as a normalized correction that is only just sufficient to see the board to help minimize hyperopic defocus. Bifocals and multifocal lenses are not typically indicated, a bit on that from Jake here. Also for application at school you might find this article useful.
Now on to that other reflex reaction. If you take away all of your child's favorite and accustomed activities, they are not going to see your love for them in it. They are most likely going to hate the sudden onset of restrictions and feel like they are being punished for being myopic. While this is clearly not your intent, this is almost certainly how they will feel. Try to make gradual changes. Reducing time in extreme and static close up needs to be a priority; so anytime you can shift phone and/or tablet activities to a tv at a greater distance this will be progress. Many parents also use book stands to help increase and encourage consistent reading distance. Introduce the 20-20-20 rule during close up right away, and as soon as possible differentials if/as needed for static close up. It is a good idea to start reducing the close work time itself where possible, but again keeping in mind how important it is that your child doesn't feel penalized for their myopia.
One thing that might help with the 20-20-20 rule is a "stretch buddy" place an object (favorite toy perhaps) at a distance from your child during close up and encourage them to "stretch their eyes" to see the object at regular intervals, picking out details on it as much as possible. Don't worry overmuch about activities like Legos and Play-doh, 3-D objects and activities tend to have a lot of shifting focus, these activities are not particularly harmful, provided there is good lighting and your child gets good distance vision as well. It is static vision that is the primary concern.
Measuring
Getting your child to look at a Snellen Chart is probably best saved primarily for measurements, and for younger children there are kid friendly snellen charts that will probably prove more engaging. It is a good idea to have several charts, it is easy to memorize a frequently used chart, so rotate often for more accurate testing. You will of course want to do centimeter measurements as well. Try to keep measuring light and fun, causing yourself or your child stress with measuring is not going to be beneficial for anyone. Jake does recommend hanging a snellen chart in the home; however for children it is probably a good idea to have well placed text stimulus beyond that, keeping some novelty to the snellen chart might well help your child engage more when you are doing measurements.
Active Focus
Children have a hard time grasping active focus but encouraging them to engage with their vision through play is easy to do, when you can get them to do this outside, even better. Some ideas here: focus games. It is important to discourage squinting and blinking unnaturally hard in order to clear blur. These are both bad habits to form and difficult to break. If you have a fairly good handle on active focus, your child is a little older and feel you can convey active focus to your child on their level by all means do so. However for the most part children are going to be more inclined to clear blur when it is part of an activity, rather than the clearing of blur being the activity alone.
Prioritize Stabilization
While it is understandable that you want to reverse your child's myopia quickly, take into account that it is quite likely that their eyes are currently getting worse. Stopping that progression is the first big step, and even if that is all you manage, that is a win. Correct use of correction for a given task, time outdoors engaging with distance vision, and good near work habits are typically enough to accomplish this goal.
Your child may or may not choose to reverse their myopia, and hard as it is for a parent to accept, that is their choice. But enabling them to stop its progression and giving them the option to reverse it, now that you know it is possible, is an advantage that most people don't have; children and adults alike.
Important
Please don't make any changes to your child's correction until you can make an informed decision. Communicate with your child about their vision, even preschool aged children can relay their own feedback. Marching your child to the optometrist every 6 months is going to be a point of stress and is wholly unnecessary, do your own measurements, and keep it light. Keep in mind how you would deal with your child concerning any other matter. Don't forget you are building better vision habits for life, there is no need to frustrate yourself or your child by pushing for fast changes and results. Remember this is not a medical condition, certainly don't neglect it, but this is more of a marathon than a sprint, so slow and steady is the way to go.
See Also
Jake's take on looking for the quick fix to Child Myopia
References
Videos by Jake: https://endmyopia.org/young-child-glasses-one-focal-plane/?fbclid=IwAR248tHeLLJ4owkJXrTocuOK_SPs4rXyBk4LOAOmP1ki2z7coxYATJ_mlB8
https://www.youtube.com/watch?v=XxOYG8weq8Y
Full playlist for Child Nearsightedness: https://www.youtube.com/playlist?list=PLgB_5pbB86Giioahj-P0PBHlervYKStyp
The EndMyopia Blog:
Child myopia diopter strategies
A Final Note
Obviously, there is the whole rest of the method to add to this, and if you need more help Jake has an add-on to the adult BackTo20/20 program. Though there are other self guided courses as well. Absolutely start with the free primer found here.