It is essential to keep your vision healthy. The best way to ensure that your vision is always in pristine condition is to visit the eye doctor consistently. However, when you get your eyeglasses, you might not know how to read your prescription.
When you look at your prescription, you will see several numbers indicating the strength of your vision in each eye. However, understanding these numbers can be confusing. Fortunately, we will explain all of the sections of your prescription to help you.
Eyeglass Prescription Abbreviations to Know
Doctors and eyeglass companies do not make it easy for patients to read their prescriptions. You will notice several abbreviations that are not always obvious. Here are the abbreviations you can expect to see when you read your prescription:
- OD: Oculus dexter or right eye
- OS: Oculus sinister or left eye
- OU: Oculus uterque or both eyes
- NV: Near vision
- DV: Distance vision
- PV: Pupillary distance
- SPH: Sphere (power of the lens)
- CYL: The Astigmatism prescription
- AXIS: The position of astigmatism
Understanding Your Eyeglass Prescription Chart
When you get your prescription for astigmatism or any eye issue causing your vision to worsen, it will have a lot of data for you to read. Here’s how to understand your eyeglass prescription chart.
#1. You Get a Prescription for Each Eye
Some people who have not been to the eye doctor do not realize that you have a prescription for each eye. Typically, vision does not deteriorate at the same pace in each eye. As a result, oftentimes you cannot use the same prescription for both.
As discussed above, OD refers to your right eye, and OS refers to your left eye. When you look at your prescription chart, you will see rows with data labeled OD and OS.
If you have trouble remembering which is which, remember that the data for your right eye will always come before the information for your left eye.
Fun fact: doctors write prescriptions this way because when they face you to conduct tests, they see your right on their left.
Sphere refers to the amount of power in each lens to correct your vision. The lens power can refer to a correction to nearsightedness or farsightedness. Your lens power is measured in diopters. However, on your eyeglass prescription chart, it will read “D.”
The number on your prescription chart will have a minus or plus sign. A minus sign indicates nearsightedness, whereas a plus symbol indicates farsightedness. The term sphere means correctable with spherical lenses. As a result, the lenses should be equal in all meridians of your eyes.
Unfortunately, not all vision is correctable with spherical lenses. Instead, some lenses need to be cylindrical. If you have cylindrical lenses, it will read CYL on your prescription. These lenses correct the vision of people with astigmatism.
Astigmatism is a common condition that affects a significant portion of the population. It refers to imperfection in the curvature of the eye. The imperfection results in blurry vision at a distance and close-up. Astigmatism usually results from the cornea or lens inside your eye having mismatched curves. Fortunately, it is very treatable with corrective lenses.
The number in the cylinder column of your prescription chart should have a plus or minus sign to indicate the type of sightedness you have. If there is nothing in this column, you do not have astigmatism.
These types of lenses use lens power that is not spherical. Instead, it is shaped so that one meridian has no curvature.
Another label you will see on your eyeglass prescription is the axis. Axis refers to the lens meridian that does not use cylinder power. If your prescription has cylinder power, it will have an axis value. The axis will have a number from 1 to 180. A value of 90 indicates a vertical meridian in your eye, whereas a value of 180 indicates a horizontal meridian.
You might notice the label “add” on your prescription. The added label refers to the added magnifying power to the bottom section of multifocal lenses. This label is not present in all prescriptions. Instead, it is only in place for people that need presbyopia corrections. The number here will range from +0.75 to +3.00 D and should be the same for both eyes.
The number next to the word “prism” indicates how much compensation is required to adjust your eye alignment issues. Very few people have prism adjustments as part of their prescription.
However, if the prism is present in your prescription, it will be indicated in metric or English fractional units.
Can You Use Your Eyeglass Prescription to Purchase Contacts?
Eyeglasses are great in all situations, but there are several reasons you might not want to wear glasses. Some may not like the look, while others may find them cumbersome. As a result, they might prefer to turn to contacts.
Unfortunately, you cannot use your eyeglass prescription to purchase contact lenses. Your eyeglass prescription is only good for eyeglasses. It does not include crucial information such as the shape and size of your eyes.
If you want to wear contacts, you need to do a contact lens fitting with your optometrist. A contact lens fitting is an additional procedure your eye doctor can perform.
A contact prescription needs more information, including the base curve of the back surface of the contact lens, the lens diameter, and the manufacturer of the contact lenses you will be using.
Additionally, your prescription might be slightly different in your contact lenses because they go directly into your eyes. Conversely, glasses sit around 12 millimeters away from your eyes.
Your Eye Prescription Is Yours
If your optometrist does not give you a copy of your prescription, make sure you ask for it. The FTC has the Prescription Release Rule that requires optometrists to present each patient with a copy of their prescription at the end of an exam. So, if you do not get your copy, make sure you ask for it.
Knowing how to read your eyeglass prescription is not essential. However, it can be useful in some situations. So, you might as well learn what your prescription means to be prepared if you need the information. Contact Art of Optiks today to schedule your comprehensive exam at one of our locations in Wayzata or Edina.