After your visit to a Calgary optometrist, you may get a prescription for eye correction. While you may know your vision needs work, these prescriptions can be hard to read for other reasons! To decipher the numbers and terms here is a quick and handy guide on how to read your eye prescription.
Understand the Headings in Eye Prescription First
The first thing you will see on your eye prescription from a Calgary optometrist is that there are different sections. Usually, these headings are two-letter abbreviations like OS, OD and OU. These abbreviations are short for the Latin terms oculus sinister, oculus dextrus and oculus uterque. These sound advanced, but their meanings are actually simple.
Oculus sinister (OS) stands for your left eye while oculus dextrus (OD) represents your right eye. Anything under the label oculus uterque (OU) is indicative of both eyes.
Examine the Numbers Second
Under each heading, you should see numbers. These numbers represent the amount of correction. Larger numbers indicate that more correction is needed.
There should also be a plus or minus sign in front of the numbers. This sign indicates if you are nearsighted or farsighted. If the number is a plus, then you are farsighted. A minus sign, by contrast, indicates nearsightedness. Specifically, the numbers are measurements of focusing power. Your Calgary optometrist may refer to this as a diopter. It denotes what lens you need.
Consider Additional Commentary Last
If there is an additional notation on your eye prescription, then it probably relates to astigmatism. Astigmatism will appear with three numbers. These numbers are measurements for spherical, cylinder, and axis.
Spherical numbers indicate the degree of your correction. Your cylinder number is the extent of your astigmatism. The axis number shows the directionality of your astigmatism.
Astigmatism refers to the shape of your eye, so it is important for precise measurements to be included in prescriptions.
When you need a Calgary optometrist, trust the experts at Urban Eyecare. Visit us at one of our two Calgary locations for a comprehensive eye exam for you or your children. We are happy to help! Call us today!
Sunridge Location (403) 280-8330
Chaparral Location (403) 453-1211
FAQs on Eyeglass Prescription
We have compiled the most commonly asked questions about eyeglass prescription
An eyeglass prescription is a set of numbers that shows your eyeglass strength. Eyeglass prescriptions typically consist of three numbers: sphere, cylinder and axis. The sphere value indicates if you have myopia (nearsightedness), hyperopia (farsightedness) or emmetropia (neither), the cylinder value indicates the amount of astigmatism and the axis value indicates the angle of astigmatism. Together, these numbers indicate the amount of strength required to focus images on the retina to give 20/20 vision.
A. Eye prescriptions play a crucial role in creating eyeglasses as they help decide several factors such as lens curve or curvature for better focus, the type of material to use to make the lens strong and rigid, whether or not the lens should be UV coated to protect it from damage, and much more.
A. Eye prescriptions are issued by an eye doctor known as an optometrist . A comprehensive eye exam is the only way to get an accurate reading of your prescription. It is important to schedule an appointment with your eye doctor annually or as often as is recommended based upon the results of the exam.
A. You can always ask your eye doctor at the end of your eye exam and they can let you know if your prescription has changed from the last time, as well as how much it has changed. If you do not have a doctor then it is recommended that you find an optometrist as annual eye exams are not only important for checking your prescription but also your overall eye health to screen for serious eye diseases.
A. Typically, a patient requires to have a new prescription every year or two, depending on the types of vision problems that they have. An eye exam does not typically change a patient’s vision prescription in a single visit. Instead, it provides a real-time picture of their eyes and in many cases, may uncover underlying conditions that may contribute to worsening eyesight.
A. 20/20 vision is considered to be normal. If you cannot read road signs clearly when driving or if a child is unable to see the board from the back of the classroom, then your eyesight is classified as poorer than 20/20.
