Looking at your eyeglass prescription, you’ll find a bunch of numbers and abbreviated terms. But what do they mean exactly? What do they say about your eyesight?
Today, we discuss a few basic things you should know about eyeglass prescriptions.
Understanding Eyeglass Prescriptions
Two of the first things you’ll notice on an eyeglass prescription are “OD” and “OS” — which stand for oculus dexter (right eye) and oculus sinister (left eye). There may also be “OU”, which means oculus uterque or “both eyes.” Today, though, some eye doctors have modernized prescriptions by using RE (right eye) and LE (left eye) instead.
Other parts of your eyeglass prescription include:
Sphere (SPH) – indicates the amount of lens power and can come with either a minus sign ( – ) for nearsightedness or a plus sign ( %20 ) for farsightedness
Cylinder (CYL) – indicates the amount of lens power for astigmatism
Axis – indicates the lens meridian that has no cylinder power to correct astigmatism
Add – indicates the added magnifying power applied to the bottom part of multifocal lenses
Prism – indicates the amount of prismatic power to compensate for eye alignment problems
Eyeglass Prescription vs. Contact Lens Prescription
Keep in mind that your eyeglass prescription is different from your contact lens prescription. Typically, eyeglass prescriptions do not specify the base curve of the back surface of a contact lens and the lens diameter. Such information can only be obtained during a contact lens consultation and fitting with your eye doctor.
Moreover, eyeglass prescriptions are based on the fact that your eyeglass lenses will be placed at a certain distance from the surface of the eyes. Contact lenses, on the other hand, are placed directly on the cornea of the eye.
Northern Virginia Doctors of Optometry is a locally owned eye care clinic with expertise in sports vision training, vision therapy, myopia control and more. Call us at (703) 573-1200, or fill out our contact form to request an appointment. We serve clients in Falls Church, VA, and the surrounding areas.