Understanding Your Eyeglass Prescription
_
My wife ordered some glasses online from Zenni. One of the
things she needed was pupillary distance. I didn’t know what it was, so I did
some research. Zenni tells you how to measure it. They even give you a tool to
do it. None the less I set out to understand the prescription so I can try to
make it easier to understand.
Like many things I suppose, it starts by admitting you have a problem. It is not a good idea to go around mad at the world because everyone switched to smaller lettering around the same time. You also have to understand that your arms are not going to get any longer.
So now you sit in the doctor’s chair to find out you have 20/what? And you would be better off with glasses. Or at least have a moment to ask yourself if it is your vanity or your curiosity that will help decide about glasses.
Like many things I suppose, it starts by admitting you have a problem. It is not a good idea to go around mad at the world because everyone switched to smaller lettering around the same time. You also have to understand that your arms are not going to get any longer.
So now you sit in the doctor’s chair to find out you have 20/what? And you would be better off with glasses. Or at least have a moment to ask yourself if it is your vanity or your curiosity that will help decide about glasses.
There is basically what a prescription looks like. So let’s break it down.
D.V. is an abbreviation of distance vision, and you might have guessed that NV is an abbreviation for near vision. What this means is a choice based on lifestyle needs to be considered.
In the example I use above, that prescription could be bifocals. Bifocals can be great due to helping with far and near vision. We have certain events when we know focusing on one issue of our vision might be best. In other words the above example could be three different pair of glasses. One for far vision, for those times when you’re out on a bike. One for near vision, for when you’re at the desk and know it’s going to be a while. And one for both, general everyday use.
Also we see O.D. and O.S. in each D.V. and N.V column.
O.S. is an abbreviation for oculus sinister, which would be Latin for left eye.
O.D. is short for oculus dexter, Latin for right eye.
Sometime you might see O.U. this would be oculi uterque or Latin for both eyes.
Prism and base are not filled out that much. This is used when there is an eye orientation of fixation that needs special attention.
Next is P.D. or pupillary distance. This can be left blank many times, but if you’re ordering online you will want these numbers. The numbers represent the distance between your pupils in millimeters. the two values are for far and near vision, the first value is the distance for your far vision and your primary P.D. The second is for near or reading distance, in short the need for bifocals or single vision for reading. It’s one more step at the doctor visit, but it is quick and the more information we have the better the glasses will be. This is an example of how the P.D. looks.
Pupillary distance - PD -- 61 (mm) Distance / 58 (mm) Reading
D.V. is an abbreviation of distance vision, and you might have guessed that NV is an abbreviation for near vision. What this means is a choice based on lifestyle needs to be considered.
In the example I use above, that prescription could be bifocals. Bifocals can be great due to helping with far and near vision. We have certain events when we know focusing on one issue of our vision might be best. In other words the above example could be three different pair of glasses. One for far vision, for those times when you’re out on a bike. One for near vision, for when you’re at the desk and know it’s going to be a while. And one for both, general everyday use.
Also we see O.D. and O.S. in each D.V. and N.V column.
O.S. is an abbreviation for oculus sinister, which would be Latin for left eye.
O.D. is short for oculus dexter, Latin for right eye.
Sometime you might see O.U. this would be oculi uterque or Latin for both eyes.
Prism and base are not filled out that much. This is used when there is an eye orientation of fixation that needs special attention.
Next is P.D. or pupillary distance. This can be left blank many times, but if you’re ordering online you will want these numbers. The numbers represent the distance between your pupils in millimeters. the two values are for far and near vision, the first value is the distance for your far vision and your primary P.D. The second is for near or reading distance, in short the need for bifocals or single vision for reading. It’s one more step at the doctor visit, but it is quick and the more information we have the better the glasses will be. This is an example of how the P.D. looks.
Pupillary distance - PD -- 61 (mm) Distance / 58 (mm) Reading
What is 20/20? anyway?
One of the first things the Optometrists wants to determine is
what your vision basically is.
You’re 20/what? So they have you look at the Snellen chart. Based on your input as to what you see, they can tell you’re at, for example, 20/30 vision. Now the eye doctor estimates that you correction will be about -0.50 then fine tunes from there.
According to the Snellen chart prescriptions can be estimated to get to a stating point.
Snellen Estimated prescription
20/10 Plano (zero)
20/15 Plano
20/20 Plano to -0.25
20/30 -0.50
20/40 -0.75
20/50 -1.00 to -1.25
20/100 -1.75 to -2.00
20/200 -2.00 to -2.50
Here’s a link to the Snellen Chart. With this link, it instructs you how to measure the “A” to determine how far away to be from your monitor to be so you can take the test. Please understand this is in no way an effort to offer medical advice, or to get you to not go to the doctor. They use way more then this chart, just liked what I found so I shared it.
The numbers are diopters. This is the unit of measure for glasses. It starts at plano or zero and goes up in ¼‘s until you get to 1.00 diopters. -.25 is a ¼, -.50 is ½ and so on. In short it is how strong your lenses are.
I think this breaks a prescription down so you can better understand it better. It is from the point of view of getting glasses. To better interpret the info and thinking about how we use are glasses. A pair just for the desk can be great. A set for outdoors can prove useful as well. The up side to getting single vision glasses is they are less expensive then bifocals. Plus, like in the example of outdoors, say biking, single vision is better. Your lower field of vision will be better. Frankly this is why ordering online is nice, single vision start at an affordable price.
You’re 20/what? So they have you look at the Snellen chart. Based on your input as to what you see, they can tell you’re at, for example, 20/30 vision. Now the eye doctor estimates that you correction will be about -0.50 then fine tunes from there.
According to the Snellen chart prescriptions can be estimated to get to a stating point.
Snellen Estimated prescription
20/10 Plano (zero)
20/15 Plano
20/20 Plano to -0.25
20/30 -0.50
20/40 -0.75
20/50 -1.00 to -1.25
20/100 -1.75 to -2.00
20/200 -2.00 to -2.50
Here’s a link to the Snellen Chart. With this link, it instructs you how to measure the “A” to determine how far away to be from your monitor to be so you can take the test. Please understand this is in no way an effort to offer medical advice, or to get you to not go to the doctor. They use way more then this chart, just liked what I found so I shared it.
The numbers are diopters. This is the unit of measure for glasses. It starts at plano or zero and goes up in ¼‘s until you get to 1.00 diopters. -.25 is a ¼, -.50 is ½ and so on. In short it is how strong your lenses are.
I think this breaks a prescription down so you can better understand it better. It is from the point of view of getting glasses. To better interpret the info and thinking about how we use are glasses. A pair just for the desk can be great. A set for outdoors can prove useful as well. The up side to getting single vision glasses is they are less expensive then bifocals. Plus, like in the example of outdoors, say biking, single vision is better. Your lower field of vision will be better. Frankly this is why ordering online is nice, single vision start at an affordable price.