How to Fill Out the Prescription for Your Eyeglasses

When buying prescription eyeglasses online, filling out your eyeglass prescription correctly is crucial to ensure the glasses meet your vision needs. Here’s a step-by-step guide to help you understand the different parts of a prescription and how to fill it out accurately.

Understanding Your Eyeglass Prescription

An eyeglass prescription is composed of several key terms and values that specify the corrective power needed for each eye. Here’s a breakdown of the common components:

 Rx SPH CYL Axis Prism ADD
OD -2.00 -1.00 175 - +2.50
OS -2.75 -1.75 80 - +2.50
PD: 65 - - - - -

  1. OD and OS:

    • "OD" stands for "oculus dexter," which is Latin for the right eye.
    • "OS" stands for "oculus sinister," referring to the left eye.
    • Sometimes, "OU" (oculus uterque) may appear, indicating both eyes.

  2. Sphere (SPH):

    • This value indicates the amount of lens power, measured in diopters (D), needed to correct nearsightedness or farsightedness.
    • If the number has a minus sign (-), it indicates nearsightedness (myopia). If it has a plus sign (+), it indicates farsightedness (hyperopia).

  3. Cylinder (CYL):

    • This value measures the degree of astigmatism, a condition where the cornea is not perfectly spherical.
    • If you don’t have astigmatism, this part may be left blank.

  4. Axis:

    • If your prescription includes a cylinder value, the axis indicates the orientation of astigmatism, measured in degrees from 1 to 180.

  5. Addition (ADD):

    • The "Add" value is for bifocal or progressive lenses and indicates additional magnifying power for reading or other close-up work.

  6. Prism:

    • This is used to correct eye alignment issues and is not present in most prescriptions.
    • Pupillary Distance (PD):
      • PD stands for Pupillary Distance, which is the measurement (in millimeters) between the centers of your pupils. It is an important factor in creating eyeglasses because it helps ensure that the lenses are properly aligned with your eyes for optimal vision.

      • Why is PD Important?

        • Proper lens alignment: The lenses in your eyeglasses need to be centered in front of your pupils for you to see clearly, especially for reading glasses, progressive lenses, or bifocals.
        • Comfortable vision: Correct PD ensures that your eyes are not strained, reducing headaches or discomfort caused by improperly aligned lenses.
      • Types of PD Measurements
        • Single PD: One measurement that indicates the distance between the centers of both pupils. This is typically used for single-vision glasses.
        • Dual PD (Monocular PD): Consists of two measurements, one for each eye, indicating the distance from the center of the nose to each pupil. This is used for progressive lenses or bifocals.
      • Knowing your PD is essential for ordering glasses online or ensuring a proper fit with prescription eyewear.

    Step-by-Step Guide to Filling Out Your Prescription

    1. Start with Your OD (Right Eye) Values:

      • Enter the sphere (SPH) value for the right eye, including the plus or minus sign.
      • If you have a cylinder (CYL) value, enter it. If not, select “None” or leave it blank.
      • Enter the axis if a cylinder value is present. Make sure the value is between 1 and 180 degrees.

    2. Fill in Your OS (Left Eye) Values:

      • Repeat the process with the left eye, entering the SPH, CYL, and Axis values as indicated on your prescription.

    3. Add Power for Reading or Multifocals (Optional):

      • If your prescription includes an "Add" value, enter it for both eyes.

    4. Prism (If Applicable):

      • If your prescription has a prism correction, fill in the prism values and the corresponding directions (base in, base out, base up, base down).

    5. Double-Check Your Entries:

      • Double-check that each number matches your prescription exactly. Even a small mistake can affect the quality of your vision with the glasses.

    Tips for Filling Out Your Eyeglass Prescription

    • Be mindful of the signs (+ or -): Mixing these up can significantly affect how well your glasses work for you.
    • Use decimals where necessary: Most prescriptions use decimals (e.g., -2.25, +1.50), so make sure you enter them correctly.
    • Contact your optometrist if in doubt: If any part of your prescription is unclear, it's better to clarify with your eye doctor than to guess.

    Common Mistakes to Avoid

    • Not including the plus or minus sign for SPH or CYL values: This can lead to ordering the wrong corrective lenses.
    • Misreading OD and OS: Make sure to match the right values to the corresponding eye.
    • Overlooking the “Add” value for multifocals: This is especially important for those who need reading or progressive lenses.

    Conclusion

    Filling out your eyeglass prescription correctly ensures you get the proper lenses for your vision needs. Take the time to understand the different terms and double-check your entries. Following this guide will help you confidently order the right prescription glasses online.

    Now that you know how to fill out your prescription, you’re one step closer to getting the perfect pair of eyeglasses!