How to Read Your Glasses Prescription?

Have you ever felt like you were trying to decipher a code while reading your eyeglass prescription? The truth is that many people are overwhelmed by the seemingly confusing array of medical abbreviations and numbers on the page. Being able to read your prescription is really helpful for finding glasses that fit your vision needs.

Abbreviations Explained in Prescription

The abbreviations and numbers on your prescription might seem confusing, To understand the abbreviations that are common on your prescription will make you better at reading as well as filling your prescription.

OD (Oculus Dexter): Latin for right eye.
OS (Oculus Sinister): Latin for left eye.
SPH (Sphere): Indicates lens power needed for focus, ranging from -10 to +10, with positive (+) or negative (-) values.
CYL (Cylinder): Corrects astigmatism, with values from -6 to +6. May not be present on all prescriptions.
AXIS: Degree and direction of astigmatism, ranging from 0 to 180.
ADD: Extra lens power for reading, from +0.50 to +3.50, used in bifocals/progressives.
Prism: Corrects vision displacement, measured in prism diopters (Δ), with directions (IN, OUT, UP, DOWN).
PD (Pupillary Distance): Millimeters between pupils, crucial for lens fitting. Can be measured at home.
Binocular: Refers to both eyes. Pupillary Distance may be listed as binocular (one number) or monocular (separate for each eye).

Nearsighted Prescription

In nearsighted (myopia) prescriptions, a minus sign (-) is placed in front of the SPH (sphere). The value after the minus sign represents the strength of the lens prescription needed to improve distance vision. The PD in this prescription indicates Binocular, If your prescription has two PD values, please fill them out separately.

A table displaying an eyeglass prescription with columns for SPH, CYL, AXIS, and ADD. The prescription shows the following values: Right Eye (OD): -0.75 SPH, -0.75 CYL, 160 AXIS; Left Eye (OS): -0.50 SPH, -1.00 CYL, 170 AXIS; Pupillary Distance (PD): 67.

Farsighted Prescription

In farsighted (myopia) prescriptions, a minus sign (+) is placed in front of the SPH (sphere). The value after the plus sign represents the strength of the lens prescription needed to improve near distance vision.

Progressive & Bifocal Prescription

A progressive prescription or bifocal prescription will include an ADD value, sometimes marked as NV. This indicates the required strength for the near prescription in your lens.

The prescription indicates a need for progressive or bifocal lenses, but requires reading glasses strength (1.75 ADD). The left eye also shows a slight astigmatism correction (-0.25 CYL at 105 degrees).

Astigmatism Prescription

If you have astigmatism, your prescription will include a number in the cylinder (CYL) column, indicating the lens power needed for correction. Additionally, the AXIS column will show a number that helps align the correction for astigmatism. The left eye (OS) has a value of -0.25, indicating a slight degree of astigmatism that requires correction.

The prescription indicates a mild astigmatism correction is needed for the left eye, as shown by the following values: Left Eye (OS): +0.00 SPH, -0.25 CYL, 105 AXIS; Pupillary Distance (PD): 66

Prescriptions With Prism Correction

A prescription for correcting eye alignment issues will include a PRISM and BASE value. These values indicate how to shape the lens for proper alignment of the wearer’s eyesight. The base value specifies the direction of the prism, which can be labeled as 'in' or 'out,' or 'up' or 'down.

The prescription with prisms has prisms in different directions in addition to the values of SPH, CYL, AXIS, and ADD. The prescription is shown as follows: Right Eye (OD): 1.50 Prism Horizontal, Base In; 1.00 Prism Vertical, Base UP; Left Eye (OS): 1.50 Prism Horizontal, Base In; 1.00 Prism Vertical, Base Down

Whether you're ordering new glasses, curious about what all those numbers on your prescription mean, or just want to feel more informed about abbreviations in prescription form, the guide has got you covered! Ready to see more clearly, in style?

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