how much of a difference is .25 on an eyeglass prescription?

Question

how much would a difference in vision clarity if an eyeglass was off by +/- .25 in prescription strength?

Answer 1

The smallest increment that is usually employed.
+/- 0.12 is used, for certain rare purposes.

Unless an individual was sensitive 0.25 would not normally be worth changing glasses for. Many people aren't sensitive to 0.50 changes. The change a small prescription makes tends to be more obvious in people with large pupils, so might, for example, only show up driving at night.

But where binocular balance problems occur, possibly most often with new glasses, +/- 0.25 in one eye can make all the difference. A patient's face can light up, with a cry of "That's it!"

Answer 2

After diligent research, I've determined that a contacts-specific exam is unnecessary for anyone who has a mild prescription and has been wearing them without problems for over 15 years like I have. I already have my measurements, but since I also like to have a valid eyeglasses prescription for backup, I'm going to just get a cheap eyeglasses exam and use that script to order contacts online. This fool and her money aren't so easily parted!