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Eyeglass Prescription Calculator

Eyeglass Prescription

Estimate lens thickness based on prescription strength and lens type.

Formula

Thickness = Base + (|Sphere| x Radius) / (2 x (Index - 1) x 10)

Frequently Asked Questions

What lens index should I choose?
Prescriptions over -4 or +4 benefit from 1.67 or 1.74 high index lenses.
Are thinner lenses worth the extra cost?
For strong prescriptions, high index lenses are lighter and more comfortable.
Does frame size affect lens thickness?
Yes, larger frames require thicker lenses, especially for strong prescriptions.

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