What's the weakest prescription for eyeglasses?

Question

What's the weakest prescription for eyeglasses?

Answer 1

Eyeglass lenses can be ground to .12 D. if that is required, or with no prescription at all.

Answer 2

Lens powers start at + or -  0.25...which is 1/4 of a dioptre

EDIT ****

LOL...true, they can be ground to 0.12...but that is never prescribed...about 30 years ago it was common to see prescriptions asking for 0.12, 0.37, 0.62, 0.87...but since then, they all stick to the 1/4's...like 0.25, 0.50...ect