Introduction
If you wear glasses, you know how essential they are to your daily life. However, not everyone knows how to read their eyeglass prescription. Your prescription is a critical piece of information that outlines your vision correction needs. Understanding how to interpret your prescription can help you make informed decisions when purchasing new glasses or contacts, and ensure that you have the most comfortable vision experiences possible. In this article, we will discuss how to read an eyeglass prescription, the common abbreviations you may encounter, the importance of understanding your prescription, tips for reading complex prescriptions, and answers to frequently asked questions.
A Step-by-Step Guide on How to Read Your Eyeglass Prescription
Your eyeglass prescription has six parts. Each section provides important information about your vision needs, and understanding each section can help you select the best eyewear for your comfort and lifestyle.
1. OD and OS
OD and OS refer to your right (OD) and left (OS) eyes. Your prescription may only list one or both of these measurements, depending on your specific vision needs. The measurement is typically written as a negative value, such as -3.50, and indicates the severity of your nearsightedness, farsightedness, or astigmatism. A higher number indicates a greater vision impairment.
2. Sphere (SPH)
The sphere (SPH) is the amount of lens power you need to correct your vision, measured in diopters. If the SPH is a negative number, you are nearsighted. If the SPH is a positive number, you are farsighted. The number is written in increments of 0.25, for example, -2.50 or +1.75.
3. Cylinder (CYL)
The cylinder (CYL) measurement, also in diopters, refers to the degree of astigmatism you have. If you have no astigmatism, this section will be marked as “SPH” or left blank. If you do have astigmatism, a number will be shown along with a direction (axis) for the lens. If the cylinder number is positive, you have mild astigmatism, while a negative number indicates a moderate or severe case.
4. Axis
The axis measurement is necessary if you have astigmatism. It is a number ranging from 0 to 180 degrees that indicates the orientation of the lens required for your left and right eyes. The axis may appear as a horizontal line on your eyeglass prescription.
5. Prism
The prism measurement is used to correct eye alignment problems. If you have a “base” location number, this represents the orientation of the prism. The power number indicates the amount of correction needed. The prism measurement can be an essential piece of information for some people but is not always included in eyeglass prescriptions.
6. Add
The “add” section applies to individuals who require reading glasses, bifocals, or multifocal lenses. This measurement indicates the power of the added magnifying portion to the lower section of the lens. The number is marked by either a + or -, depending on whether it is needed for distance or near vision.
Common Abbreviations Used in Eyeglass Prescriptions
Like most medical documents, eyeglass prescriptions use a variety of abbreviations. Here are the most common abbreviations you’ll find:
OD or Oculus Dexter
This abbreviation stands for “right eye.”
OS or Oculus Sinister
This abbreviation stands for “left eye.”
SPH or Sphere
This abbreviation refers to the lens power needed to correct your vision.
CYL or Cylinder
This abbreviation indicates the degree of astigmatism you have and the direction (axis) needed for the lens.
ADD or Addition
This abbreviation only appears on prescriptions for reading glasses, bifocals, or multifocal lenses. It indicates the power of the added magnifying portion of the lens.
The Importance of Understanding Your Eyeglass Prescription
An accurate eyeglass prescription is critical for your comfort and safety. Wearing the wrong prescription can cause headaches, eyestrain, and visual discomfort. Unfortunately, eyesight can change over time, so it is essential to keep your prescription up to date. Wearing an outdated prescription can worsen your eyesight and indirectly lead to other issues such as headaches, dizziness, and squinting, which can strain your eyes and eventually lead to other preventable eye problems.
Tips for Reading Complex or Challenging Eyeglass Prescriptions
Some prescriptions may be difficult to decipher, making it nearly impossible to find the correct eyewear. Here are some tips for reading complex prescriptions:
1. Ask Your Eye Doctor for Help
Your eye doctor can help explain the details of your prescription, and even help you interpret the abbreviations. It’s always a good idea to call your doctor’s office if you have questions or concerns about your prescription.
2. Bring Your Prescription to the Optician
An optician is an expert in eyewear design and can review your prescription with you to ensure that you are selecting the best frames and lenses for your needs. They can also offer advice on the best treatments and options available to correct your vision impairment.
3. Use a Prescription Reader App
Some smartphone app developers have launched prescription reader apps that are designed to help you read and understand your prescription quickly and easily.
Frequently Asked Questions About Reading Eyeglass Prescriptions
Here are some common questions people ask about understanding their eyeglass prescriptions:
Q: What if I don’t know my prescription or can’t find it?
A: If you can’t find your eyeglass prescription, contact your eye doctor’s office and request a copy. They will gladly provide one for you, or you can schedule an examination to obtain a new one.
Q: How often should I get a new eyeglass prescription?
A: It is recommended that you get an eye exam annually to ensure that your prescription is up-to-date, but it is generally recommended that you replace your glasses when you experience any changes in your vision or if your glasses become damaged or outdated.
Q: Why do I need to have an eyeglass prescription if I only need reading glasses?
A: Over-the-counter reading glasses may help with some of the symptoms of presbyopia, but wearing the wrong glasses can cause headaches, eye strain, and blurred vision. An accurate prescription will ensure that the reading glasses or multifocal lenses you purchase are the right ones for your vision needs.
Q: Are there any risks associated with purchasing eyeglasses online?
A: Purchasing eyeglasses online can be a risk, as poorly measured or misaligned glasses can cause eye strain and headaches. Always ensure that you purchase eyeglasses from a reputable seller that follows proper fitting and measurement guidelines.
Conclusion
Knowing how to read your eyeglass prescription is essential to ensure that your vision is clear, and your glasses are comfortable. An up-to-date prescription is necessary, and understanding it can help prevent eye strain and damage to your vision. Ask your eye doctor for help if you have any questions or concerns about your prescription.
