If you have had an eye exam, you may be familiar with an eye prescription. To understand the glass prescription meaning well, you may need to understand each element of the eye prescription. So, in this post, we will show you the eye prescription explained.
Eye Prescription Explained: Sphere, CYL, Axis, and PD
Before proceeding with the glasses prescriptions explained, you should know some basic information. OD refers to the right eye and the OS refers to the left eye. The minus sign means nearsightedness and plus sign means farsightedness. After learning the basic information, we will show you the meaning of some important elements in the eye prescription.
Sphere: Sphere means the correction of nearsightedness or farsightedness, equal in all meridians of the eye. The sphere number refers to the lens power of the glasses. The higher the number, the stronger the prescription is.
CYL: CYL refers to an eye condition called astigmatism and is caused by an irregular or rugby ball-shaped cornea. The higher the number, the more irregular the shape of your eyes. If nothing appears in the CYL column, it means that you have no astigmatism or it is so light that you do not have to correct with glasses lenses.
Axis: Axis means the angle between meridians of an astigmatic eye. The axis in your prescription is usually measured from 1 to 180. The number means the vertical meridian of the eye and the number 180 means the horizontal meridian. For more information, you can read the post: Full Explanations: Sphere, Cylinder and Axis in Glasses
PD: pupillary distance, is the distance between the center of each pupil and the bridge of your nose measured in millimeters. PD is very important for making prescription glasses because it is used to determine where you look through the lens of your glasses, so it should be measured as accurately as possible.
ADD: it indicates that if you need a prescription for reading and is applied to bifocal and varifocal lenses to correct presbyopia.
Prism: this number shows whether you have a muscle imbalance in your eyes. It is less common to see this box filled in. The prism is usually written in fractions.
Base: it relates to the prism and the position of the lens.
These are all elements of the eye prescription. After reading this eye prescription explained post, you have learned the meaning of each element in the prescription. But it is recommended to develop a good habit of eye use so as to keep them healthy.
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To sum up, this post has shown the eye prescription explained. If you have any different ideas of eye prescriptions, you can leave a message in the comment zone. If you have a problem with glasses or sunglasses, please feel free to contact us via the email firstname.lastname@example.org and we will reply to you as soon as possible.