When you visit the eye doctor for an annual eye exam, they will check your eyes for vision problems, astigmatisms and other ailments. If you have trouble seeing, the optometrist will write you a prescription for glasses to correct your vision. While most people who were eyeglasses in Chillicothe, OH know if they are nearsighted or farsighted, the details on the prescription can be difficult to understand.
Understanding your prescription is important to understanding exactly what’s going on with your eyes and will help you communicate more effectively with your eye doctors or future eyewear providers. If you are lost when looking at your eyeglass prescription, here are some key terms that should help make it—and your vision—clearer!
Which eye is which?
One of the first things that might confuse you about your prescription is that there is no “right eye” or “left eye.” Instead, eye doctors traditionally use the Latin terms “oculus dexter” and “oculus sinister” to convey the right and left eye. Typically, these will be conveyed with the acronyms OD (right eye) and OS (left eye).
If you’re lucky enough to have the same prescription in both eyes, your prescription may read “OU” or oculus uterque, meaning “both eyes.”
While these terms are traditional, some eye doctors are choosing to simplify their prescriptions by using RE and LE for “right eye” and “left eye.”
Understanding lens power
For each eye on your prescription, there will also be a few columns and values that make up the lens power for your eyeglasses. To reach your final prescription, there are a few different terms to identify:
- Sphere (SPH): The sphere of each eye indicates the lens power required for you to see objects clearly at a distance. This power will be measured in diopters (D) and will have a minus sign (-) or a plus sign (+) to indicate nearsightedness or farsightedness. For example, if your sphere prescriptions are OD -5.00 and OS -4.75, you are nearsighted, and if they are OD +2.0 and OS +2.25, you are farsighted. The farther your numbers are from zero, the more correction your eyes require to see with 20/20 vision, or close to it.
- Cylinder (CYL): The cylinder value indicates the lens power required to correct an astigmatism, a defect in the eye caused by a deviation in spherical curvature resulting in distorted images, if you have one. The cylinder lens power is shaped with one meridian that has no curvature and another meridian perpendicular to it with maximum curvature and lens power needed to correct the astigmatism.
- Axis: The axis value is directly related to astigmatisms and the cylinder power. Axis refers to the location of the meridian with no cylinder power and is described with a number 1 through 180. A value of 90 refers to the vertical meridian of the eye, while 180 refers to the horizontal meridian of the eye. An axis number will always follow a cylinder power, if there is one.
- Add: The add is the lens power added to the bottom of multifocal glasses to treat presbyopia, which is the loss of near focusing ability that occurs as you age. Add is always a positive power and the same in both eyes.
It’s important to note that these values are only applicable for eyeglasses, not contact lenses. Contact lens prescriptions require different types of information identified in a fitting.
Is it time to get yourself some new glasses? Visit Price Family Eye Care Professionals LLC to receive an eye exam and shop our wide selection of eyeglasses in Chillicothe, OH. We’ve served families and individuals with our variety of eye care services for over 35 years! Call today to make an appointment.
Categorised in: Eyeglasses
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