Frequently Asked Questions/Differentials

Frequently Frequently
Asked Questions
(please read this!)

General


About Myopia	LASIK	Glasses & diopters	Mindset	Troubleshooting

The Process — EndMyopia Glossary


Active Focus	Habits	Measurement	Normalized	Differentials	Astigmatism	Other

EndMyopia


Skepticism	About EM	Paid course	Other eyesight conditions	Ineffective Myopia Treatments

What are differentials?

Differentials are glasses for close up. They are not used as the primary stimulus to improve eyesight, rather they help relieve eye strain and prevent hyperopic defocus when using screens up close for long periods of time.

They are essential in preventing axial elongation and the worsening of myopia.

Jake says:

The differential prescription is a reduced prescription specifically for close-up use.

Using a full prescription meant to correct myopia at long distances while focused up-close, will lead to more lens-induced myopia. To reduce the eye strain and focal plane change associated with full prescription wear up-close, we use a prescription specifically for close-up.

For myopes <2 diopters: No glasses should be necessary for close-up.

For myopes >2 diopters: Often a reduction of 1 to 2 diopters makes sense for close-up. To determine the exact prescription one may use a test lens kit, or a visit to a rehab sympathetic optometrist, or extrapolate the correction need by using the centimeter calculator.

Rehab specific: Reduction of prescription to introduce an ergonomically comfortable blur horizon is well advised.

How to choose a differential prescription is here.