I have astigmatism and short-sightedness. In your prescription they put several numbers to define how the lenses for your glasses should be built.

Your prescription can change over time, but I have always had astigmatism, that hasn't changed.

However, something has always confused me, some eye-doctors seem to prescribe me glasses with indications for astigmatism and less adjustment for nearsigthness, while others just give me more adjustment for nearsightness without astigmatism adjustment.

From the article above, it seems you have to have 3 numbers in your prescription, however I don't remember ever seen a third number in mine. It might be something to do with difference in standards in different countries.

I have had prescriptions like:

  • -1.25: this number is the adjustment for my short-sightedness, we call it "increment" in my country, although it may seem counter-intuitive. But the proper name is diopter.
  • -0.75 +0.8: As I said, it seems I may be missing one number, but it is clear a 0.75 diopter for my short-sightedness and +0.8 diopter for the astigmatism.

As personal experience, I think that when they prescribe me glasses with both elements I feel better. However I would like to understand if there is a practical difference.

Is it the same to have a prescription with a higher diopter for short-sightedness, basically a more powerful lense, than a prescription with less short-sightedness adjusment and a separate adjusment for the astigmatism?

What is the practical difference? Because in the end I manage to see, I just think I "feel" better with the glasses that have both adjustments.

  • Welcome to Medical Sciences! Please take the tour and read the help center. For reasons mentioned in this post and in How to Ask, we require prior research information when asking questions. See this list of helpful resources. Please help us to help you and edit your question to provide more information on what you have read on this subject, what made you ask this question, and any problems you are having understanding your research. If you found nothing, what did you Google?
    – Carey Gregory
    Oct 5 '21 at 0:31
  • One of the things people often misunderstand here about our prior research requirement is that we expect graduate-level research. We don't. What we expect is you've read a general article or two on places like WebMD, Wikipedia, Mayo, etc. so we're not starting from ground zero with basic concepts and terminology. For example, this article would have been a good addition to your question. I don't know how to read an eyeglass prescription but after reading that short article I could at least make sense of one.
    – Carey Gregory
    Oct 5 '21 at 4:04
  • Okay, let us know when you're done editing your question.
    – Carey Gregory
    Oct 6 '21 at 4:58
  • @CareyGregory I think I edited it enough now. Don't know what you think.
    – Dzyann
    Oct 6 '21 at 12:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Browse other questions tagged or ask your own question.