Secrets of Your Eyeglasses Prescription

Dr. Robert Dinga

We understand the frustration of staring at an eyeglass prescription filled with confusing numbers and cryptic abbreviations. Decoding this seemingly indecipherable language can be a daunting task, leaving many individuals feeling lost and uncertain about their vision needs. However, fear not! We are here to demystify the intricacies of your eyeglass prescription, empowering you with the knowledge to take control of your visual well-being.

Understanding the Prescription Format

An eyeglass prescription typically consists of several components, each representing a specific aspect of your vision correction requirements. These elements work together to provide a comprehensive roadmap for crafting lenses tailored to your unique needs. Let’s delve into the intricate details:

understanding your eye prescription

Sphere (SPH)

The sphere, or spherical power, is a numerical value that indicates the degree of nearsightedness (myopia) or farsightedness (hyperopia) present in your eyes. A negative value signifies myopia, while a positive value indicates hyperopia. This measurement is essential for correcting refractive errors and restoring clear vision at various distances.

Cylinder (CYL)

The cylinder represents the amount of astigmatism, a condition where the cornea or lens of the eye has an irregular curvature, causing blurred or distorted vision. A cylinder value of zero indicates no astigmatism, while a non-zero value quantifies the degree of astigmatism present.


The axis is a numerical value ranging from 0 to 180 degrees, specifying the orientation of the astigmatism correction. It determines the direction in which the cylinder power should be applied to compensate for the irregular curvature of the eye.

Addition (ADD)

The addition, also known as the “near vision power,” is a value typically found in prescriptions for individuals with presbyopia, a condition that affects near vision as we age. This additional power is incorporated into bifocal or progressive lenses to provide clear vision for reading and other close-up tasks.

Pupillary Distance (PD)

The pupillary distance, or PD, measures the distance between the centers of the pupils in millimeters. This measurement ensures that the optical centers of the lenses align perfectly with your eyes, optimizing visual clarity and comfort.


In some cases, a prism value may be included in the prescription. Prisms are used to correct eye misalignments or binocular vision problems, such as double vision or eye strain.

Interpreting Additional Symbols and Abbreviations

Your eyeglass prescription may contain various symbols and abbreviations that provide additional information about your vision needs. Here are some common examples:

Embracing Your Eyeglass Prescription

Armed with this comprehensive understanding of your eyeglass prescription, you can now confidently engage in discussions with your eye care professional and make informed decisions about your vision correction options. Embrace the knowledge you’ve gained, and take an active role in safeguarding your precious eyesight. Remember, your eyeglass prescription is a powerful tool that unlocks a world of clarity and visual comfort. By decoding its intricacies, you empower yourself to navigate the realm of vision care with confidence and ease.


Clinic, C. (2024, May 15). Got a New Eye Prescription? Here’s What It Means. Cleveland Clinic.

How to Read an Eyeglasses Prescription. (2023, April 18). American Academy of Ophthalmology.

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