How to read my eye doctor's prescription? An easy guide to understanding your vision.

¿Cómo leer mi receta del oftalmólogo? Guía fácil para entender tu visión
If you've just come out of your annual checkup and you're holding a piece of paper full of numbers, plus signs (+) and minus signs (-), it's normal to feel a little confused. Understanding your eye prescription is the first step to making smart choices when buying glasses online. In this guide, we explain in simple terms what these letters mean and how to interpret them so your next pair of glasses is perfect. What do OD and OI mean on an ophthalmologist's prescription?

The first thing you'll see are these two abbreviations. They come from Latin and are the international standard:

  • OD (Oculus Dexter): Refers to your eye right.
  • OI (Oculus Sinister): Refers to your left eye.

Sometimes you may see AO, which means "Both Eyes". As a general rule, optometrists write the information for the right eye first, and below it, the information for the left eye.

 

The three key values: Sphere, Cylinder, and Axis. This is where we get into the technical part. Most recipes are divided into three main columns:

1. Sphere (SPH or ESF)

This number indicates the power of the lens necessary to correct your vision.

  • If the sign is negative (-): You have myopia, which means you see poorly from a distance.
  • This value will only appear if you have astigmatism. Astigmatism occurs when the cornea has an irregular shape (like a football instead of a round one), causing blurred vision at any distance. If this box is empty or says "0", you do not have astigmatism.

    3. Axis (AXIS or EJE)

    If you have a value in the Cylinder column, you will necessarily have one in the Axis column. This number (between 1 and 180) indicates the orientation in which the astigmatism should be placed in the lens.

    Other important values: Addition and DP

    This field usually appears for people over 40 or 45 years old who suffer from presbyopia (age-related farsightedness). The Addition is the extra power needed to see up close and is used to manufacture progressive or bifocal lenses. It is always a positive value (+).

    Pupillary Distance (PD)

    Why is it important to understand your prescription before buying glasses online?

    Buying your glasses from an online optician allows you to access a much wider variety of frames and more competitive prices. However, accuracy is key. Correctly entering this data guarantees that:

    1. Avoid dizziness or headaches for a wrong graduation interpreted.
    2. Save money by choosing the right type of lens for your prescription (e.g., thinner lenses for prescriptions) high).
    3. Improve your quality of life with a clear vision from the first minute.

    Do you have your prescription handy but still have questions?At our online optician's, we're ready to advise you. You can send us a photo of your prescription, and our experts will take care of preparing your lenses for you. Your eye health is our priority!