So far we looked at centimeter measurements, Differential Prescription Part I, and the subject of plus lenses.
We now know how to use the centimeter measurement to help us choose the correct prescription, with the help of the centimeter calculator. This will come in to be helpful in an upcoming installment, where we will discuss the correct distance prescription for your child. If your child is currently wearing glasses, we will want to adjust that prescription to make sure that we only correct as much as is actually necessary.
For now, we will focus on the prescription that is more important, however – the close-up prescription.
As we covered to some extent before, close-up focus is the root of all of our myopia problems. If your child is myopic enough to where focusing on an object 50cm away is difficult, he/she is likely using the regular prescription to view close-up objects – this greatly amplifies the effects of myopia, and should be avoided at all costs. Instead, we want to use a much smaller prescription, that sets the child’s focus to where the 50cm object is still readable, but requires active focus to be seen clearly.
If your child has only mild myopia, we can start limiting the focal range by using plus lenses. These refocus the convergence point in the child’s eye so that our reading distance is also the distance that is the edge of the close-up focus ability of the child’s eye. Doing this allows us to not only reduce eye strain (the ciliary muscle is now contracted less, as we moved the focal plane), but also allows the child to ‘push’ focus (discussed in an upcoming installment in more detail). The combination of these two aspects is very powerful in reducing and reversing myopia for the child.
In case you also have access to the adult program, you will find some of these topics also covered in great detail. We approach a bit differently with the child, as attention span and motivation are just not the same in adults, as they are in children. Having both programs is ideal to give you both the ‘raw’ approach that we use for adults, as well as the modified one that is better suited for the child.
We already covered one way you can choose a close-up prescription for the child – if the myopia degree is less than -2D per the centimeter calculator, we can (and should) use plus lenses. This is as easy as going to a drug store that sells reading glasses, grabbing a book, and trying different prescriptions strengths with the child. As always we want to make this a fun, exploratory trip. Kids love experiments, riddles, and play, so this prescription treasure hunt can be great fun, if orchestrated with a little care.
For higher myopia degrees, we want to start with a change of 1.75 diopters from the centimeter calculator. So if your child has a -3D results from the centimeter calculator, we would want a -1.25D prescription for close-up work.
As the child progresses, and as individual physiology varies, we want to make sure that this prescription creates a limited viewing distance at the child’s normal close-up distance. So things are sharp until the point where the child focuses, and just barely begin to blur there. At an average 50cm, that would mean that text is still very readable, but just has a small amount of blur. We will further discuss ergonomics, and how to avoid the close-up creep (where the child will inch closer and closer to the screen) in upcoming installments.
If you are in the +Therapist option of the Web program, you have access to direct feedback for prescription recommendations. Please do take advantage of these. And if you are just in the Basic program but have questions, don’t hesitate to ask, anyway!
Combine this prescription with the previous installment, discussing choosing frames that the child truly loves, and will use.
This being an easy and gradual process, combining these aspects allows us to neutralize the negative impact of close-up and minus prescriptions, and coming up we will discuss various ways to add stimulus to begin reversing the effects that previously increased the child’s myopia.
What do we want to focus on, today?
The main concern is choosing a prescription strength that does not go overboard. If the image is blurred to close, the child will not want to wear the glasses. We want just an available edge to work with. Let’s not be aggressive about this, and choose a prescription degree that just puts the mildest of blur at the far end of the close-up viewing distance.
Along with that, we really want to pick glasses that the child significantly enjoys. It just has to last for a month or two (we all know that kid’s tend to drop one interest for another fairly quickly). We just need enough time to where picking up that frame for close-up becomes a habit, and we are already winning. Some parents have found fun tricks, such as attaching the glasses with a string, to hang from the neck, allowing the child to just grab it as needed. This doesn’t work for all, but I’ve seen some fun, creative implementations. Especially if it’s ‘cool’ (for boys), or ‘stylish’ (for girls) – I am generalizing greatly, forgive me, the desire to partake and use these prescriptions increases.
In upcoming installments we will discuss some of the other core aspects of this practice. Ergonomics are important, and of course the range of stimuli we can apply once we have these prescription aids.
Let’s go get those differential prescriptions. If you have questions (or just some fun photos of your excursion), please do post them in the forum!