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Article: How to Read Your Contact Lens Prescription

How to Read Your Contact Lens Prescription

If you are new to wearing contact lenses, understanding your contact lens prescription can be confusing. However, your prescription is an important piece of information that will ensure you have the correct lenses prescribed for your eyes. In this blog post, we’ll break down how to read your contact lens prescription using an example.

What is a Contact Lens Prescription?

A contact lens prescription is a written document from your eye doctor that specifies the lenses you need to correct your vision. It contains information on lens parameters like base curve, diameter, power, and material.

How to Read Your Contact Lens Prescription

Your contact lens prescription will have several abbreviations and numbers. Let’s take a closer look at each of these elements using the following example prescription:













Acuvue Oasys

Air Optix

Hydraclear Plus

Lotrafilcon B


OD and OS

OD means “oculus dexter,” which is Latin for “right eye.” Conversely, OS means “oculus sinister,” which is Latin for “left eye.” In the example prescription, OD has a spherical power of -2.50 and OS has a spherical power of -2.00. Both eyes also have astigmatism as indicated by the cylinder and axis numbers.

Sphere, Cylinder, and Axis

“Sphere,” “cylinder,” and “axis” are abbreviated as S, C, and A, respectively. These numbers indicate the amount of correction you need for nearsightedness, farsightedness, and astigmatism. In the example prescription, the sphere powers are given for each eye (-2.50 for OD, and -2.00 for OS), along with cylinder and axis information for both eyes.

Base Curve and Diameter

The base curve refers to the curvature of the lens, while the diameter is how wide the lens is across. These numbers help determine the fit of the contact lens on your eye. In the example prescription, the base curve is 8.6mm, and the diameter is 14mm for both eyes.

Brand and Material

The prescription may also indicate a particular brand and material for the lenses. This information will assist in finding the appropriate contact lenses for your needs. In the example prescription, the right eye is prescribed Acuvue Oasys with Hydraclear Plus, while the left eye is prescribed Air Optix with Lotrafilcon B.

Final Thoughts

Understanding how to read your contact lens prescription may feel overwhelming at first, but it's crucial to ensure the health and comfort of your eyes with contact lens use. If you have any questions regarding your contact lens prescription, don't hesitate to contact your optometrist or optician for clarification. With proper understanding and care, contact lenses can provide you with clear and comfortable vision.

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