How do you read a prescription correctly?
The parameters included in your prescription by a specialist (ophthalmologist or optician) can also be found on the lens packaging and on the individual blisters. Are you wondering what mysterious abbreviations like SPH, BC, AXIS mean? We explain all lens symbols and markings. Find out how to read a lens prescription!
Remember to have your eyes examined by an ophthalmologist before buying lenses, even if you have previously worn glasses and have a prescription for them. Lenses require an appropriate eye examination and individual fitting to your eyes. An ophthalmologist or optician will select the type and power of lenses for you. If you want to change your current lenses, consult your ophthalmologist. Even lenses with the same power differ depending on the materials, technology, and design used.
Basic markings on the prescription
RE/LE
Right eye/left eye. You may have different vision defects in both eyes or the same defect. It may also happen that you only need correction for one eye.
SPH or PWR - Power
This is the power of vision correction, the so-called spherical power of the lens. It may have a positive [+] value for farsighted people, a negative [-] value for nearsighted people, or a zero value (0.00, no power needed, can also be indicated with the word 'Plano').
DIA or D - Diameter
This means the width of the lens, given in millimeters.
BC - Curvature
Base curve, radius of curvature (the value that defines the posterior optical radius of the lens), the so-called lens curvature. This value shows the curvature/convexity of the back surface of the lens.
CYL - Cylinder
Value that determines the power of astigmatism.
AXIS/AX - Axis
The astigmatism axis represents the angle along which the lenses should correct astigmatism.
ADD - Addition
Near addition: extra power, occurs in multifocal lenses.
Dominance
A prescription for eyeglass lenses is not the same as a prescription for contact lenses!
A glasses prescription is not the same as a contact lens prescription!
Regarding the differences, it is also important to note that a glasses prescription cannot be used to select contact lenses. The latter are described not only by values related to the organ of vision, but also by values that characterize the lenses themselves. In addition, the power of lenses differs - since they sit directly on the eye - from the power of eyeglass lenses.
Additional markings on the packaging
Dk/t
Oxygen permeability. It indicates the amount of oxygen allowed through the lens material.
EXP
Expiration date.
LOT
Batch number: