Eye glass prescription: Can somebody explain what my P.D. reading means?!

Eye glass prescription: Can somebody explain what my P.D. reading means?

On my eye glass prescription, it has a P.D. reading that says 57/54. I've looked all over the internet, and according to what I've read, a P.D. reading is the distance between your pupils in milimeters. I've been shopping the internet for seeing-eye glasses. Every time I have to type in my P.D. reading, it just has a slot for one number. I don't know whether to put 57, 54, or something inbetween. Can somebody explain why I have a 57/54 and what it means and what I should put for my PD reading when I order glasses online? Thanks.

If they are asking for only one number, you'd want to enter the 57. Unless you are ordering reading glasses, then you would enter the 54 number. The 57 is the distance between your pupils when you are looking at a distance, and since your eyes converge to read, you would use the lower of the two numbers for ordering glasses to be used ONLY for NVO (near vision only)

This Pupillary distance measurement is so that the lab can place the optical centers of the lenses (which are the clearest part of the lenses) right in front of your eyes. Without this measurement, they can't center the lenses in front of your eyes and this can effect how you see out of them. Its especially important for those with stronger prescriptions to make sure that their PD measurement is accurate, as they tend to be more sensitive to it. Its also important for people who wear bifocals and progressive lenses to make sure their segments and channels are placed at the right spot.

So, for Distance vision only glasses, you want to enter the 57.
For Near Vision only glasses, you want to enter the 54.