How to find nv add on prescription?

Eyeglasses prescriptions use the same standard format and common notations. This makes them universal, meaning that they can be read anywhere in the world.

The article will use a sample eyeglasses prescription to walk you through how to read your own.

Providers who write eyeglasses prescriptions may Latin abbreviations. While they have been used for a long time, Latin abbreviations are becoming less common.

On your prescription, you might see abbreviations for specific terms instead.

For example, the word "power" is sometimes written as "PWR." Another common term is "sphere" which is sometimes abbreviated as "SPH" on a prescription.

Here's what the Latin abbreviations on the example prescription mean:

In addition to terms and abbreviations, eyeglasses prescriptions also include a lot of numbers.

You'll also see some mathematical symbols like the plus sign (+) and minus sign (-).

In the example prescription, the first number to the right of OD is -2.00. This is the "sphere" part of the prescription, which may be abbreviated as "SPH."

The sphere number indicates whether you have nearsightedness or farsightedness.

Nearsighted people have trouble seeing things that are far away. Farsighted people have trouble seeing things that are up close.

You'll also see a plus sign or minus sign before the number.

The next number in the sample prescription is -0.50. This is the "cylinder" measurement. On your prescription, "cylinder" might be abbreviated as "CYL."

The cylinder measures the degree of astigmatism in your eye. The number shows how much lens power will be needed to correct astigmatism.

The next number is x 180, which is read as "axis 180." On your prescription, "axis" is sometimes abbreviated as "X" or "AX."

This number is an angle in degrees from 0 to 180. If you have astigmatism, this number points to where it is in your eye.

The cornea is the clear covering of your eye. It is the part of your eye that does most of the focusing.

In the example, the left eye's "sphere" number is plus one (+1.00) DS.

The letters DS mean "diopters sphere." This number means the left eye’s correction is spherical with no astigmatism.

In other words, the right cornea probably has a slightly oblong shape while the left cornea is very close to being perfectly round.

In the example, the ADD number of +1.75 notes how much power needs to be "added" to the distance prescription. This addition helps a person see better for reading and other activities that they do up close.

Younger people's prescriptions usually do not have an ADD number. While some young people can have near-focusing problems, it usually develops as you approach 40.

Some people think the ADD number is the power needed for over-the-counter (OTC) reading glasses (or "readers"), but it's not the same thing.

To get the right number, you need to do a little math.

To find the right reading glasses, add the sphere number to the ADD number.

In the above example, for the right eye, this would be -2.00 and +1.75, which equals -0.25. For the left eye, add +1.00 and +1.75 to get +2.75.

Next, look at the cylinder measurement and the axis measurement.

In the example, the correct number for the right eye is -0.25 -0.50 x 180 while the correct number for the left eye is simply +2.75.

You may also see a few other words or abbreviations on your eyeglasses prescription:

Your eyeglasses prescription may include Latin abbreviations, numbers, and mathematical signs. These numbers are used to describe the shape of your eye and the correction you need in your glasses.

For example:

If you are an individual who experiences sustained eye issues, you may have developed some habits and workarounds to make life easier. You may place your eyeglasses in a certain place at home so that you know you won’t lose them when you go to sleep. You may even have a separate pair of eyeglasses that you can wear when you are playing tennis, golf or another one of your favorite sports. Whatever the case may be, you have likely developed a routine that keeps you seeing as clearly as possible.

Nevertheless, there may be situations where you need to abandon some of these manual workarounds in order to see more clearly. As just one example, you may be happy with your eyeglass prescription, but you are having more trouble reading. This can be true whether you are trying to read the day’s newspaper at your kitchen table or an important work document on your computer.

Yes, you can squint and try to power through your vision issues. But having said this, there may come a time when you need to convert your eyeglass prescription to reading glasses. While this isn’t necessarily a difficult task, it is not something that you can simply breeze through. It can be easy to trip up. Therefore, it is critical to recognize and understand the common steps in this process.

We are here to help. At Rx-Safety, we sell all different types of glasses—including prescription glasses. We have seen the conversion process many times, so we want to do our part to demystify this process.

Below you will find our guide to converting your eyeglass prescriptions to reading glasses. By following the steps and advice that we have presented below, you will be well on your way to completing this important task.

To convert to reading glasses, you only need two things. You will need your current eyeglass prescription and a calculator. From there, you will do some simple math to ensure that your conversion is accurate.

Let’s start with your current eyeglass prescription. Every eyeglass prescription contains several abbreviations and numbers. For instance, “OD” stands for oculus dexter (“right eye” in Latin) and “OS” stands for oculus sinister (“left eye”). To successfully convert your eyeglass prescription to reading glasses, you will need several other metrics. You will need a distance prescription, sphere power, and an add. The distance prescription is self-explanatory. Sphere power is the main strength of your eyeglass prescription, and it is written in increments of 0.25. The add stands for the additional correction that is used for reading glasses.

Essentially, the formula for converting an eyeglass prescription to reading glasses is adding your sphere power to your add power. To illustrate this process, it is helpful to provide some examples.

For instance, let’s say that you have an eyeglass prescription that has a sphere power of -1.25, a cylinder of -1.00, an axis of 83, and an add of 1.50. Once again, the formula states that we should add our sphere power (-1.25) to our add power (1.50), resulting in plus 0.25. From here, if this were to become a single vision reader, the end result would be plus 0.25, minus 1.00, at 83 degrees.

As another example, if we had a sphere power of 2.00, a cylinder of -1.50, an axis of 130 degrees, and an add of 1.50. We would follow the same steps as above. Simply put, we would add the sphere power of 2.00 to the add of 1.50, resulting in plus 3.50. The final prescription reading for these reading glasses would be plus 3.50, minus 1.50, at 130. By this point, you can see that both the cylinder and axis are never going to change. The only thing that will change will be the sphere power because we are adding the added power to it. Simple enough, right?

This conversion formula can lead to some interesting scenarios. For instance, if you have a sphere power of -1.50 and an add of 1.50, you will end up with 0.00. You would be wearing a single vision reader of 0.00 and this will be included with the same cylinder and axis.

The situation becomes somewhat more complicated if your sphere power is not the same for both eyes. As just one example, let’s say that your right eye has a sphere power of -3.50 and your left eye has a sphere power of -2.75. The remaining parts of your prescription are the same for both eyes. For instance, let’s assume that your cylinder is -0.75, your axis is 140 degrees, and your add is 1.50. From there, you would follow the same formula as described above. Specifically, you would take your right eye sphere power of -3.50 and add it to your add (1.50), resulting in -2.00. For your left eye, you would take -2.75 and add it to 1.50, equalling -1.25. This would result in a right eye of -2.00, -0.75 at 140, and a left eye of  -1.25, -0.75 at 140. It is as simple as that.

As you can see, the math itself isn’t that tricky. The one thing that could trip you up, however, is the addition of both positive and negative numbers. It is easy to mix your signs, which could result in reading glasses that are not properly converted for your eyesight. Because of this, it doesn’t hurt to have a calculator when you are doing this conversion. Take your time and don’t hesitate to check your math twice. If you put on your reading glasses and think that something is off, go back and see if you correctly made your conversion. While you will eventually get it right, you can avoid some frustration and wasted time by going slow and checking your math.

By this point, we hope you have realized that it isn’t an extremely complicated process. Yes, it does require you to do some simple algebra. If you feel like you’re weak at math, you may be intimidated by this fact. Luckily, however, the algebra is extremely basic. Slowing down, being deliberate, and checking your work is an effective playbook here.

For multi-focal glasses, as well as reading and computer glasses, your Rx will include an ADD or NV value. This number always has a (+) sign. Rx Note: The type of Rx glasses may be noted on a prescription, such as DV [Distance Vision/nearsightedness] and NV [Near Vision/reading].