How do you read your eye test prescription?
Reading your eye test prescription is essential when it comes to purchasing the right glasses for you. An eyeglass prescription consists of several components that must be properly interpreted to determine the correct lens strength and type. Whether you’re ordering glasses online or at an optical store, understanding the basics of how to read your prescription can help ensure a successful purchase.
An eyeglass prescription includes three variables: sphere (SPH), cylinder (CYL) and axis (AXIS). Sphere indicates the amount of correction needed to correct nearsightedness or farsightedness. It is measured in diopters (D). Cylinder measures the amount of astigmatism present in the eye, which is also measured in diopters (D). Axis is used to indicate the angle of the correction, measured in degrees between 0 and 180.
When reading an eyeglass prescription, it is important to look for the symbols “+” or “-”. A positive number (indicated by “+”) indicates a need for magnification, while a negative number (indicated by “-”) indicates the opposite. For example, if the SPH column reads +2.50, this means the patient will require glasses with a magnification level of +2.50 diopters. If the CYL column reads -3.00, this means the patient will require glasses with a corrective power of -3.00 diopters. The AXIS column refers to the angle of the correction, measured in degrees from 0 to 180.
In addition to the three main variables, an eyeglass prescription may also include additional information such as the pupillary distance (PD) and type of lenses. Pupillary distance is the distance between the two centers of the pupils and is used to calculate the appropriate frame size. It is usually measured in millimeters and should be indicated on the prescription. The type of lenses required can vary depending on the patient's visual needs, such as single-vision, bifocal, trifocal or progressive lenses.
Knowing how to read your eyeglass prescription is an important first step in selecting the right pair of glasses. With this knowledge, you can easily compare different frames and lenses online. By understanding the basics of eyeglass prescription, you can confidently purchase prescription glasses online to suit your unique vision needs.
