A recent question in the forum:
Can you define what a “differential prescription” is exactly? I understand it refers to either a plus lense or reduced minus lenses but the term just seems mysterious to me.
Of course we discuss all the terms in the Vision Improvement Course.
But it makes sense, that we should have a glossary of terms, as we are using these references quite a bit in the blog and the forum. As I find time I will keep adding these as short articles, and eventually put them all into a glossary of terms category.
Differential Prescription
The #endmyopia Method for myopia rehabilitation is made up of The Four Pillars.
One of them is about prescription use.
As explained in How Myopia Happens, a big contributor to progressive myopia is the way we use our glasses. Wearing glasses meant for distance vision, while focused up-close, will increase your myopia.
To prevent this from happening, we use a different prescription for close-up use.
If your myopia degree is about -2 diopters or less, you probably don’t need glasses at all to see clearly at the average 50cm distance that you likely are from your computer monitor. In this case, you should not wear any glasses while focused up-close.
In case you are actively working on improving your eyesight, the Vision Improvement Course recommends a small plus lens (reading glasses) prescription, for those with less than -2 diopters of myopia. This is the differential prescription, used only during close-up.
If your myopia degree is higher than -2 diopters, you likely can’t see clearly without your glasses, even at the short 50cm or so distance to your computer monitor. In this case you need a reduced minus prescription (not plus, ie reading glasses), to still see your computer clearly, but with less strain than your full distance vision prescription would cause.
So in the higher myopia cases, the differential prescription is a lowered minus lens. The reduction is usually between 1.5 and 2 diopters less, than your regular distance prescription.
Prescription use should be well understood by you, before making any changes.
Prescriptions can have a very significant effect on your eyesight health, as well as your safety (while driving for example). Arbitrarily reducing or changing your prescription is something I would strongly discourage you from doing. Consult a behavioral ophthalmologist and/or take the time to very clearly understand the effect of prescriptions on your vision.
