Prescription ExplainedRest easy! Let us show you how to enter your prescription when ordering your glasses. If you have an inkling to learn more about optics, just click on the “Read More” option at the end of the answer. The following are 2 common optical prescription formats; they both contain the exact same prescription information. If you have any question regarding to any of those fields, please follow the index number and look up from our Term Explainations or Abbreviation Quick Look-Ups. 
O.D. represents your right eye, and O.S. your left. Sometimes your doctor may write O.U. which refers to both eyes. 2. a) What do I need to know about my PD? PD stands for “Pupillary Distance”, it’s the distance measured in millimeters (mm) between your 2 pupils. This measurement ensures that the optical centre of the lens sits right in front of your pupils. Most usually it is written down as 1 number (as shown in sample 2); where an average man’s PD is around 64, woman’s is around 60, and 42-54 for children. Usually, your distance PD should be within 58 to 72. When it is written in one number, it is a binocular PD meaning that your eyes are symmetrical and are equal distance from your nose. (As shown in sample 1) That’s perfectly fine. Please enter the bigger PD number on your prescription into the PD field, and make sure you note all PD information in the "Any Extra Information" field before you add the pair into your shopping cart -- we’ll know what it means, and if necessary we’ll contact you to clarify. We also recommend you to send us your prescription paper by faxing it through our toll free number at 1(888)858-2048. Alternatively, you can capture your prescription by scanning it, or taking a picture of it with your cellphone/camera/webcam. Then, just send the file to us at cs@eyewearmagic.com and have us take a look at it for you. There are two possible reasons for having 2 PD numbers. The first possibility is that one is your distance PD and the other is your near PD. An example of this is usually something along the lines of “65/62” (as shown in the above prescription sample), where there’s a 2-4mm difference between the two numbers, and are usually in their 60’s. The second possibility for 2 PD numbers is that it’ s a monocular PD. A monocular PD is needed when the eyes are asymmetrical and one eye is slightly closer to the nose than the other. An example of a monocular PD is “32/33”; they are usually in the 30’s since it is close to half of your binocular PD, and there is usually only a 1-2 mm difference from each other. c) What if there is no PD on my prescription? Many clients tell us that their prescription does not contain a PD (pupillary distance) measurement. But the PD measurement is actually a crucial part of your prescription. For the eyeglass dispenser, the PD measurement determines how to position the lens in the frame such that the optical centers sit directly in front of your pupils. To find out your PD, please just give your optometrist"s office or your previous eyeglasses vendor a quick call and they can let you know your PD measurement over the phone. What if they don"t have my PD on file? In case your optometrist and your previous eyeglasses vendor don"t have your PD on file, you can still measure it with a friend. Please note that the result is your distance PD. Please also note that we do not recommend you to use this self-help method if your prescription strength is stronger than 6.00 -- in this case, please contact you optometrist and have him/her to measure it for you for ensuring the accuracy of the test. To measure your distance PD: Step 1: Your friend will stand right in front of you at the same eye level. Step 2: Make sure that when measuring, you are not looking at your friend, but at the wall behind him/her. This is to ensure that your eyes are focusing on somewhere far, to measure the distance PD. Please do not measure it all by yourself against your mirror, as you must be looking at far when measuring your distance PD. Step 3: Have your friend place a millimeter ruler right underneath your eyes and measure the distance from your right pupil to your left (in the centers of the black dots in your eyes) in millimeters. It should be in the 50"s or 60"s, sometimes 70"s. We recommend you to repeat this process to ensure the accuracy of the measurement. If you are required to provide your reading PD, the reading PD is the distance PD minus 3 (e.g. if the distance PD is 65, then the reading PD is 62). 3. What should I do about those extra remarks on my prescription? Most often, remarks consist of recommended lens coatings, specific lens index or function. Just write down whatever remark is written on your prescription form in the "Any Extra Information" box of the order form. Also, if you have requested anything specicial (e.g. lens shape alteration, prism correction) through our customer service representatives, please note in the "Any Extra Information" field as well. (As far as lens coatings go, fortunately our lenses include all the essential coatings absolutely free of charge, so there ’s no need to worry about paying extra for coatings!) If you are in any way confused about your prescription, please send us your prescription paper by faxing it through our toll free number at 1(888)858-2048. Alternatively, you can capture your prescription by scanning it, or taking a picture of it with your cellphone/camera/webcam. Then, just send the file to us at cs@eyewearmagic.com and have us take a look at it for you. 4. Do I need to enter the ADD powers? If you are getting single-vision distance glasses, you can omit the ADD fields of your prescription; enter only the SPH, CYL and AXI fields. If you are getting single-vision reading glasses, bifocal or progressive glasses, you will need to enter all the information including the SPH, CYL, AXI and ADD. If there is no ADD power on your prescription form, just leave it at "none" on the order form. The ADD power refers to your need for near-vision correction, formally known as presbyopia. The eye has an inherent ability to relax its muscles when focusing on a far away point, or contract its muscles to see something up close (anything within an arm’s length of you is considered close). This ability is called “accommodation”. As aging progresses, the eye’s ability to accommodate weakens; people over 40 generally start to experience blurriness when looking at close objects. Reading is the primary concern with the development of presbyopia, and that is why presbyotes will often opt for “reading glasses” which correct only near-vision. If your prescription does not have any CYL or AXI, leave the CYL and AXI fields blank on the order form. Otherwise, just enter exactly what you see on your prescription form into the CYL and AXI, paying careful attention to the minus (-) or plus (+) sign of the CYL. Remember, a minus (-) CYL and a plus (+) CYL have completely different functions; and a CYL power is always accompanied by an AXI value. Your prescription may have “DS” or “SPH” in the cylindrical fields; it simply means that there is no CYL so you can leave it blank when ordering. A prescription without CYL and AXI is called a spherical prescription which means you do not need any astigmatism correction. Astigmatism occurs when an eye has 2 different focal points causing blurry vision. The difference in focal points is represented by the Axis in units of degrees ranging from 001-180. That is why any cylindrical power is always accompanied by an axis value. Just enter the SPH that you see on your prescription form paying very careful attention to whether it is a plus (+) or a minus (-) SPH. Remember, a minus (-) SPH and a plus (-) SPH have completely different functions; and as the power increases, higher index lenses are recommended for thinner and lighter lenses. If you see “PLANO” or “PL” in the SPH, it means you do not need any vision correction. Your glasses will purely be for cosmetic purposes. The spherical power in your prescription represents the “amount” of help your eye needs to see light clearly as it travels from one index of refraction to another. The lenses in your glasses act as a “bender” of light rays as it travels into your eye, bending them in a way such that your eye will be able to get a clear image of your surroundings. The higher the spherical power, the thicker the corrective lenses. That is why with higher spherical powers, lenses with a higher index of refraction are recommended so that lenses can be thin and light, ideal for comfortable, long-term usage. D.V. stands for “Distance-Vision”; it comprises of everything you see that is further away than an arm’s length of you. You use your distance-vision for regular day-to-day activities such as driving, watching TV, etc. If you are getting single-vision distance glasses, omit the N.V. information and enter only the D.V. portion. N.V. stands for “Near-Vision“; you use your near-vision for looking at thing up close within an arm’s length of you, primarily for reading. If your prescription is purely for single-vision reading glasses, your optometrist/ophthalmologist may choose to write the reading prescription in the N.V. portion (as shown in sample 2). If this is the case, omit the D.V. portion and enter only the N.V. portion when ordering your reading glasses. 9. What does it mean when there are no decimal points? Your optometrist or ophthalmologist may prefer writing your prescription without the decimal points. If they write “-300” it really means -3.00, and “+250” is the same as +2.50. For the axis values, there are no decimal points and “4” can be written as “04” or “004”. 10. How do I know what lens index I need? Determining the ideal lens index is based entirely on the combined power of the SPH and the CYL. Example 1: if your SPH is -3.50 and CYL is -2.50, the combined power is -6.00. Example 2: if your SPH is +4.00 and CYL is -1.00, the combined power is +3.00
**If you see “PLANO” or “PL” in the SPH, it means you do not need any vision correction. Your glasses will purely be for cosmetic purposes. Appendix A: Abbreviation Quick Look-Ups Here’s a quick look-up of commonly used abbreviations and what they mean:SPH: Spherical Power; read more here CYL: Cylindrical Power; read more here x: Axis(AXI); for example, “x56” means the axis is 056; read more here DS: Dioptres Sphere; there is only SPH power, no CYL, no AXI; read more here PL: PLANO; this means you have no corrective power, SPH = 0; read more here OD: Dexter; right eye; read more here OS: O culus Sinister; left eye; read more here OU: O culus Uterque; both eyes; read more here DV: D istance Vision; read about it here NV: N wear Vision; read about it here NVO: Near Vision Only; refers to a prescription designated only for single-vision reading glasses; read more here PD: Pupillary Distance; distance between your pupils measured in millimeters (mm); read more here ARC: anti-reflection coating; read about it here SRC: scratch-resistant coating; read about it here
As always, if you still have questions or comments, we are only one click away! 
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Prescription Explained
Rest easy! Let us show you how to enter your prescription when ordering your glasses. If you have an inkling to learn more about optics, just click on the “Read More” option at the end of the answer.
The following are 2 common optical prescription formats; they both contain the exact same prescription information. If you have any question regarding to any of those fields, please follow the index number and look up from our Term Explainations or Abbreviation Quick Look-Ups.
2. a) What do I need to know about my PD?
c) What if there is no PD on my prescription?
3. What should I do about those extra remarks on my prescription?
4. Do I need to enter the ADD powers?
9. What does it mean when there are no decimal points?
10. How do I know what lens index I need?
As always, if you still have questions or comments, we are only one click away!
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