Prescription Glasses |
How to fill in the prescription accurately for prescription glasses?Nowadays, many people like to buy prescription glasses online since the glasses sold online are very cheap at the price meanwhile of same if not better quality as those sold in a retail store. It is quite obvious that before you purchase prescription glasses, you should go to your eye specialist and get your eyes tested. You can not buy prescription glasses online without having the test done. Most of the online stores ask the buyers to fill in the prescription details so that the lenses can be made according to them. The complete prescription for prescription glasses should include the PD (Pupillary Distance) value, Spherical, Cylindrical, Axis and Add value. And the letter OD and OS respectively means the right eye and the left eye. Sph- Provides the depth of the focal field in the lens. A negative sign in front of the number, indicates that you’re nearsighted while the positive sign means that you are farsighted. Cyl and Axis- The two designations may be included if you have an astigmatism. Cyl will describe the amount of correction you need to overcome this, and Axis is the angle at which the correction is placed. Please remember that there is always an Axis entry beside a Cylindrical value. Add- Add value indicates the strength of the overlay on the lens for reading or the bottom near correction for multi-focal lenses. It is typically the same positive number, for both eyes. By the way, if “DS” or “SPH” is noted on your prescription, it means that there is no correction needed in the corresponding entry and you may just leave this field blank when ordering your prescription glasses. PD- PD is is the distance (usually measured in millimeters) between the centers of the pupils in each eye. This measurement is used to accurately center the lenses in the frame that you have selected which will also affect the comfort of wearing prescription glasses and this figure does not expire with age. Sometimes a prescription will list two numbers in the PD entry, such as PD 65/62. The number 65 is the distance PD while the second number 62 is the “reading” or “near-vision” PD which is used if you are ordering single-vision reading glasses. Occasionally a PD is written as 32/34.5 which are the measurements from the center of the nose to either eye. So the PD should be the sum of the two, 32+34.5=66.5. You can enter this as 66 or 67 since one millimeter difference for the PD value doesn’t make a big deal. When you order glasses online, in order to make sure you can get the satisfied prescription glasses, please double check the prescription entered in the order form before submitting.
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