How to Read your Prescription


Welcome to Ottika's comprehensive guide on how to read your eyewear prescription. Understanding the numbers and symbols on your prescription is the key to achieving clear vision. Let's break down the essential elements:


1. Sphere (SPH):

  • Indicates the main lens power to correct nearsightedness (negative values) or farsightedness (positive values).
  • Written in diopters (D); the higher the number, the stronger the prescription.

2. Cylinder (CYL):

  • Addresses astigmatism, a condition caused by irregular cornea or lens shape.
  • Positive or negative values denote the degree of astigmatism correction needed.

3. Axis:

  • Specifies the angle (in degrees) for astigmatism correction.
  • Ranges from 0 to 180; helps align the cylindrical power correctly.

4. Add:

  • Applies to multifocal prescriptions (bifocals, progressives) for additional power needed for reading or close work.
  • Written as a positive value.

5. Prism:

  • Indicates the amount of prismatic power required to correct eye alignment issues.
  • May be present for conditions like strabismus.

6. Base:

  • Corresponds to the base direction of the prism (up, down, in, out).

7. Pupillary Distance (PD):

  • Measurement between the centers of your pupils.
  • Ensures proper alignment of the optical center of the lenses with your eyes.

8. Lens Material and Coating:

  • Specifies the type of material for your lenses (e.g., high-index, polycarbonate).
  • Coatings may include anti-reflective, anti-scratch, or UV protection.

Reading Example:

  • OD (Right Eye): -2.00 -1.25 x 180
  • OS (Left Eye): -1.75 -1.50 x 90
  • Add: +2.25
  • PD: 64

Understanding the Example:

  • Right eye has myopia (nearsightedness) of -2.00 diopters with astigmatism of -1.25 at an axis of 180 degrees.
  • Left eye has myopia of -1.75 with astigmatism of -1.50 at an axis of 90 degrees.
  • Additional power for reading (+2.25) is included.
  • Pupillary distance is 64.


Understanding your prescription empowers you to make informed choices for your eyewear. At Ottika, our team is ready to assist you in finding the perfect frames and lenses tailored to your unique prescription. Explore our online collection for a seamless eyewear experience.

Your clear vision is our priority at Ottika!