An eyeglass prescription can appear confusing due to the various abbreviations, numbers, and terms used by optometrists. However, understanding this information is crucial for choosing the correct lenses that will provide you with optimal visual clarity and comfort. In this comprehensive guide, we’ll decode your eyeglass prescription, making it simple and understandable.
Key Components of Your Eyeglass Prescription
- Sphere (SPH)
- This indicates the strength of your prescription measured in diopters. Positive numbers (+) indicate farsightedness (hyperopia), while negative numbers (-) signify nearsightedness (myopia).
- Cylinder (CYL)
- The cylinder value measures astigmatism, an eye condition causing blurred or distorted vision. It also uses positive or negative numbers.
- Axis
- Axis numbers range from 0 to 180 degrees and indicate the orientation of the astigmatism correction in your lenses.
- Addition (ADD)
- ADD is the additional magnifying power needed for reading or other close-up tasks, typically seen in prescriptions for bifocals or progressive lenses.
- Prism
- Prism correction helps align your eyes if they don’t naturally align properly, preventing double vision or eye strain. Prism corrections are not common and will specify the direction of the prism correction (up, down, in, out).
- Pupillary Distance (PD)
- PD measures the distance between your pupils in millimeters, ensuring your lenses align perfectly with your eyes. Accurate PD measurement is essential for clear vision.
Reading Your Prescription
A standard prescription might look like this:
- OD (Right Eye): -2.25 (SPH), -1.00 (CYL), 90 (Axis)
- OS (Left Eye): -2.00 (SPH), -0.75 (CYL), 80 (Axis)
Here’s how to interpret this:
- OD stands for Oculus Dexter, meaning your right eye.
- OS means Oculus Sinister, referring to your left eye.
In this example, the right eye has -2.25 diopters of myopia with -1.00 diopters of astigmatism corrected at 90 degrees. The left eye has slightly less myopia and astigmatism at a different axis.
Types of Prescriptions and Lenses
- Single Vision Lenses: Correct vision at one distance, either near, intermediate, or far.
- Bifocals: Have two sections, typically one for distance and one for reading.
- Progressive Lenses: Provide a seamless progression of lens strengths from top (distance) to bottom (near).
- Specialty Lenses: Such as computer lenses, designed for optimal comfort during prolonged screen use.
Tips for Getting the Most from Your Prescription
- Always keep your prescription updated—typically every 1-2 years.
- Request clarification from your optometrist if any part of your prescription seems unclear.
- Store your prescription safely; it is crucial when buying new glasses or lenses.
Importance of Accuracy
An accurate prescription significantly impacts your visual comfort and clarity. Incorrect lenses can cause headaches, blurred vision, dizziness, or eye strain. Always consult a professional optometrist regularly to maintain accurate prescriptions.
Understanding your eyeglass prescription empowers you to make informed decisions about your vision care. By knowing what each term and value represents, you’ll be better equipped to choose glasses that not only correct your vision but enhance your overall quality of life.