How would I convert a -8.50 glasses to an x/20?

Question

My glasses prescription is -8.50. I was wondering what that would be in 20/20 conversion.

Answer 1

Do you mean with out glasses? With that type of prescription i would guess that you would not even be able to see the big E on the eye chart and that is 20/400, i would think you would be count fingers (only able to see fingers, not anything on the eye chart) with out any glasses.

I hope that answers your question.

Answer 2

Depending on your age and health of the eyes, it would be reasonable to assume you would achieve 20/20 vision after a recent exam. However, you cannot determine what visual acuity you have just based on the -8.50. I could also wear a -8.50 and see 20/30 if that was the best I could be corrected to. If you really want to know, call the office that did the exam and ask what your expected visual acuity is with your latest correction.