How to read your eye prescription: decoding the numbers and abbreviations
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When you leave an ophthalmology consultation, your eye prescription may be full of initials, numbers and abbreviations that look like a secret code. Understanding it not only gives you peace of mind but helps you understand your eye health better. At Clínica Castellote, we want to explain simply how to read your prescription and what each part means.
What do OD and OI mean on an eye prescription?
You will see these abbreviations on almost every prescription:
- OD (Oculus Dexter): Refers to the right eye.
- OI (Oculus Sinister): Indicates the left eye.
- OU (Oculus Uterque)/AO (both eyes): When the prescription is the same for both eyes.
Prescription numbers: sphere, cylinder and axis
- Sphere (SPH): Indicates whether you are short-sighted or long-sighted. A number with a – sign indicates myopia, while a + sign indicates hyperopia.
- Cylinder (CYL): Shows the degree of astigmatism, an irregular curvature of the cornea affecting the sharpness of vision.
- Axis: Related to the cylinder, it expresses the orientation of astigmatism in degrees (from 0 to 180).
Other important details on your prescription
- ADD (addition): Used for people with presbyopia to indicate the extra prescription strength needed for near vision.
- Prisms: Correct eye alignment problems or squint.
- AV (Visual Acuity): Reflects the ability to see with the prescribed correction.
Why is understanding your eye prescription important?
At Clínica Castellote, ophthalmology specialists in Castellón, we recommend that patients know the basics of their prescription so they can better understand their vision problem and discuss questions with their ophthalmologist. This does not mean interpreting everything on your own; having a basic understanding will give you more confidence.
Reading an eye prescription may seem complicated, but this basic guide will help you decode the most common abbreviations and numbers. Most importantly, always consult your ophthalmologist to adapt the prescription to your needs and assess your eye health comprehensively.