How To Read Your Eyeglass Prescription
When you look at your prescription for eyeglasses, you will see numbers listed under the headings of OS and OD. They are Latin abbreviations: OS means the left eye and OD means the right eye. Occasionally, you will see a notation for OU, which means something involving both eyes. In general, the further away from zero the number on your prescription, the worse your eyesight and the more vision correction you need. A plus sign in front of the number means you are farsighted, and a minus sign means you are nearsighted. These numbers represent diopters, the unit used to measure the correction, or focusing power, of the lens your eye requires. Diopter is often abbreviated “D.”
For example, if your prescription says -1.00, you have one diopter of nearsightedness. This is a fairly mild amount of nearsightedness. If you are -4.25, that means you have 4 and 1/4 diopters of nearsightedness. This is more nearsighted than -1.00, and requires stronger lenses. Similarly, +1.00 would be a small amount of farsightedness and +5 would be more.
For people who have astigmatism, there will be three numbers in your prescription. The general form for writing these numbers is S x C x Axis
The S refers to the “spherical” portion of the prescription, which is the degree of nearsightedness or farsightedness discussed above.
-2.00 +1.50 x 180
+3.50 +3.00 x 45
How To Use These Numbers
Understanding what these numbers mean can make it a lot easier to order new glasses online. If you have your frames handy, you can simply input the dimensions of your eyewear when placing an order. This guarantees you receive frames that perfectly fit your face.
To order the best possible glasses for your lifestyle, a little preliminary research makes a big difference. Explore the selection at Marvel Optics to get a feel for the different designs available and discover eyewear that fits you in all the right ways.
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Measure Your Pupillary Distance
Your pupillary distance is pretty much what it sounds likethe distance between your pupils. Its a helpful measurement for optometrists and opticians who are preparing your lenses. The goal is to have your pupils centered behind each lens for the best vision correction possible.
You can measure your pupillary distance at home and use it when buying glasses online or in-store. Although your pupillary distance shouldnt impact the size of your glasses, it will affect the placement of the optical center of the lens .
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How To Read Eyeglasses Size
This article was co-authored by Alexander Knezevic, MD. Dr. Alexander Knezevic is an Ophthalmologist at the Macy Eye Center in Los Angeles, California. He also is Medical Staff at Cedars-Sinai Medical Center and is a Clinical Instructor of Ophthalmology at UCLA. He graduated with his Doctor of Medicine degree from the University of Nebraska Medical Center, and he completed his Residency at the McGaw Medical Center of Northwestern University. Dr. Knezevic did his Fellowship at the University of California-Irvine, and hes board certified by the American Board of Ophthalmology. Additionally, Healthgrades has awarded him their Honor Roll award. This article has been viewed 87,727 times.
Knowing how to read your eyeglasses size will help you find the best fit, especially when shopping for glasses online. Your glasses size is made up of 3 numbers that indicate measurements in millimeters, such as 45 20-135. The first number will be the eye size, which measures the width of 1 lens. The second number indicates the bridge width, or the distance between the lenses. The third number, or the temple length, tells you how long the arms of the glasses are. To find the perfect fit, you can take your own measurements or have them taken by an optician. Use your measurements to find a comfortable and flattering pair of eyeglasses with the perfect fit!
How To Find Your Glasses Measurements
Your glasses measurements may be closer than you think. Usually, the frame manufacturer prints the size numbers on the inside of the glasses temples. Sometimes they will print them on the bridge.
Look for a series of three numbers. They will look similar to this:
1. Lens width: The first 2-digit figure represents the lens width (typically between 31mm-60mm
2. Bridge width: The second 2-digit figure represents the bridge width
3. Arm length: The third 3-digit figure measures the length of your frame arms
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What To Know About Farsighted Prescriptions
Farsightedness, or hyperopia, is a refractive disorder that makes close objects harder to see than distant objects. It happens because the distance from the cornea to the retina is too short or because the cornea of your eye is not curved enough.
If youre farsighted, light focuses behind your retina instead of squarely on it.
For a farsighted prescription, the strength of the lenses will be marked with a plus sign. The more farsighted you are, the higher the numbers will be. For instance, a lens prescription of +4.50 is a stronger prescription than one thats +2.00.
Is Your Pd Written On Your Glasses
Your pupillary distance is a facial measurement unique to you, therefore will never be printed on your glasses. Your PD or dual PD is the total or combined distance between your pupils and is not determined by the size of a spectacle or sunglasses frame. The same goes for your ocular heights which the vertical component of your lens centration.
For instructions on how to measure your PD,
For instructions on how to measure your OC heights,
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How To Find Glasses Size By Measuring With A Credit Card
Yes, there really is another use of your card, apart from paying for your favourite purchases, and it works. You probably did not know that the size of a credit card in height is approximately the same as the width of a medium size glasses lenses! Below are instructions on how to find your glasses size by using credit card as measuring device.
- Take any credit or debit card
- Stand in front of a mirror or place your smartphone somewhere steady and use your selfie camera. Place the credit card on the bridge of your nose and under your eyebrow.
- If the edge of the card extends further than the edge of your eye, your size is – small
- If the edge of the card ends at the outer edge of your eye, your size is – medium
- If the edge of the card ends before the outer edge of your eye, your size is – large
Find Your Glasses Arm Length
Go back to your temple measurement and use it as a reference for finding the ideal arm length for your glasses:
- If your temple width is 129mm or less, choose an arm length between 135mm and 140mm
- If your temple width is between 130mm-139mm, choose an arm length between 140mm and 145mm
- If your temple width is wider than 139mm, choose an arm length of 150mm or above
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Glasses Measurements: How To Find Your Frame Size
Have you ever looked at one of the arms of your glasses and thought, What do those numbers mean? Or, perhaps you didnt realize that glasses had numbers displayed on them in the first place?
The numbers inscribed on the inside of the arm are eyeglass measurements. Theyre one way to find a glasses size that feels comfortable on your face and does a good job of correcting your vision. Differences of just a few millimeters can significantly change how glasses look and feel on your face, so they can be an important part of getting to know your eyewear.
Want to know your glasses size? Well teach you how to read and take these measurements, as well as how to pick out some perfectly sized frames.
Get To Know Your Nose Bridge
You want glasses that will sit effortlessly on your nose without sliding up or down. Look at the bridge of your nose in the mirror and note how close your eyes are to it.
If your nose is relatively narrow, youll want a narrower bridge. The opposite is true if your nose is wider. You can also take stock of where exactly the bridge of your nose is on your face: If its high up, you might look for glasses with a higher bridge, near the brow line. If its lower, you might be a great candidate for Low Bridge Fit frames.
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Features Of Progressive Lenses
With the proper head position, the wearer can have a clear and continuous vision at all distances from the distal point to myopia through the progressive lens. When the eye moves from one area of vision to another, the eye adjustment process is natural and smooth, without any visual fluctuations. With natural vision and better adaptability, it is in line with physiological optics. The mid and near vision area is relatively small: Some wearers may feel that the gradient area of the progressive lens is smaller, which limits the width of the saccadic eye and requires increased head movement in order to achieve the same reading range. At medium and short distances, the wearer needs to coordinate certain head movements.
Why Is This Important To Know
A common misconception among patients is that their eye size is fixed and that if the eye size of their current glasses is, say, 54 , then they need their new glasses to be a 54 as well, says Wolfe. This is not necessarily the case, since the AA and BB values interact with each other.
Everyone comes in different shapes and sizes, and that includes the dimensions of your face. A pair of glasses that works well for one person may not fit comfortably for another. These simple facial measurements make finding a pair of snug glasses easier for the patient.
For example, you may have a very rectangular frame with an eye size of 56, and a 16mm distance between lenses, explains Wolfe. If you wanted to switch to a rounder look, you may get a similar fit with a frame that has an eye size of 50, but an 18mm distance between the lenses. This is why its important to try frames on in person, rather than simply going by the eye size number of your current glasses.
Especially when looking to purchase a new pair of glasses online, most people focus on the optical prescription. Dont get us wrong, the prescription is essential, but making sure the glasses sit correctly on your face is just as important. While you can use these sizes as a guide, every pair of glasses is different, so if youre looking for the best fit, definitely seek the guidance of a professional. Next, see if you can use FSA or HSA for glasses before you check out.
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Measure The Glasses And Sunglasses Size With A Ruler
If you can’t find any numbers or specifications on your old sunglasses or glasses, don’t worry. That just means it’s time to test your measuring skills.
Take a ruler or a tape measure and carefully measure the size of the glasses, following the graphic below.
Since too many numbers can get a little confusing, the glasses and sunglasses in Lentiamo’s online shop are labelled S , M or L , according to the lens width.
Once you have the correct measurements, head over to our sunglasses section and find your favourite pair.
Where Is My Glasses Size
The dimensions of your glasses are predominantly labelled on the interior surfaces of your frame, usually on one of the temples. Occasionally, they can be located on the temple tips or frame front, but that is uncommon.
The size will always be written as three listed numbers. E.g. 44 22 145
For sunglasses, the frames lens and bridge width are still usually printed, but can sometimes omit the temple length. This is because certain manufacturers produce their sunglasses using an average size of temple a one size fits all sort of approach.
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Learn How To Read Glasses And Sunglasses Measurements
The best place to start is with the eyeglass measurements on a pair you already own. Take a closer look at the temples of your eyewear. Search for the three little numbers on the inside of the temple of your glasses. These three numbers are the frame’s measurements. They will look somewhat like this: 5119 144
From left to right, these eyeglass measurements appear in the following order: lens width, bridge width, temple length. Sometimes a fourth number will be noted on the arms, which is your lens height. All of these measurements are in millimeters.
|Lens WidthThis is the horizontal width of each lens at its widest point. It typically ranges from 40mm to 60mm.
|Bridge WidthThis is the distance between your two lenses. In short, the bridge width is the space where your frames fit against your nose. The size of this piece ranges from 14mm to 24mm.
|Temple Length This is the length of the temple from each screw to its temple tip, including the bend that sits on your ear. This measurement does not vary as much as the others. The temple is typically 120mm to 150mm long.
|Lens HeightThis is the vertical height of your eyeglass lenses at the widest point of the lens within the frame. The lens height is important when measuring bifocals or progressive lenses.
In some cases you will know the Width of the Whole Frame.
Converting measurements to glasses size
|Convert measurements to size
What Is The Average Glasses Frame Size
Frames for adults vary slightly for men and women, but are generally made to standard sizes similar to shoes or clothes. Depending on the brand, there may be size options available in the lens width, bridge width and temple length.
- Average adult lens widths: 40 60mm
- Average adult bridge width: 14 24mm
- Average adult temple lengths: 120 150mm
*Oversized frame styles can exceed these dimensions, especially womens butterfly sunglasses, oversized mens frames or bespoke editions.
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What Do The Numbers On The Inside Of Glasses Frames Mean
Do you ever wonder about the weird numbers on your glasses? Youll notice a number like 51-16-142 printed on the inside of the frames. You might think of it as a normal number but it says a lot about your glasses dimensions.
These numbers denote three vital pieces of information about your glasses frame size. Heres our simple frame size guide to help you comprehend easily.
Lens Diameter – It represents the horizontal width of the lenses. A normal lens diameter falls in the range of 40mm to 62mm.
Bridge Width -It suggests about the distance of the lenses and the size of the nose bridge of the frames. A normal bridge width ranges from 14mm to 24 mm.
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A Glossary Of Eye Prescription Abbreviations
- ADD stands for the additional lens power needed to make it easier for you to read. This number is seen on prescriptions for reading glasses or the lower portion of bifocal or progressive lenses.
- Axis is a number between 1 and 180. It indicates exactly where the astigmatism appears on your eye.
- BO, BI, BU, BD stand for base out, base in, base up, and base down. These abbreviations tell the eyeglass manufacturer exactly where to position the prism on eyeglasses that correct double vision.
- CYL stands for cylinder, or the amount of astigmatism in your eye. The cylinder and axis together help correct astigmatism.
- DV is an abbreviation for distance vision. This number indicates whether you have nearsightedness or farsightedness.
- NV stands for near vision, or the amount of power that needs to be added to make reading easier.
- OD means oculus dexter, or your right eye.
- OU stands for oculus uterque, or both eyes.
- OS is oculus sinister, or your left eye.
- PD means pupillary distance. Monocular PD is the distance from your pupil to the middle of your nose. Binocular PD is the distance from one of your pupils to the other pupil.
- Prism is used if you have double vision. It indicates the amount of prismatic power your glasses need to correct for differences in the alignment of your eyes.
- SPH means sphere, or the power of the lens that will correct your eyesight.
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How Are The Numbers On Glasses Printed
There are numerous ways to label spectacles and sunglasses frames. The most common methods are laser etching, pad printing, hot foiling or using adhesive labels, discreetly applied to the interior surfaces of the frame.
Laser etching is highly accurate and uses a CNC laser beam to rapidly burn the surface of the spectacle or sunglasses frame. This process can be used on acetate or metal and can even be used to mark the lenses.
Pad printing is one of the most common methods of labelling spectacles or sunglasses frames. Using an automated rubber stamp, coloured ink is transferred from a plate called a cliché and applied to the frame. It is fast, accurate and highly repeatable, suited for low to high production volumes. The only drawback to this process is the curing time of the ink to fully set.
Hot foiling is similar to pad printing but instead uses sheet metal foil and a heated metal stamp. The stamp is embossed with the frames numbers and dimensions which is then pressed against the sheet foil onto the surface of the acetate frame.
Adhesive labels are occasionally used to mark the dimensions of spectacles or sunglasses frames. If present the label/s usually reside within a recess as way of making them level or flush with the surface of the frame.