06/01/2026
What do Sphere (SPH), Cylinder (CYL), and Axis mean in an eye prescription?
This table is an eye glasses prescription (Rx). It tells the optician how to make lenses that help you see clearly.
SPH (Sphere)
This shows if you are short-sighted (myopia) or long-sighted (hyperopia).
Plus (+) number → long-sighted (difficulty seeing near)
Minus (−) number → short-sighted (difficulty seeing far)
If it’s 0.00, no spherical power is needed.
Example from the image:
OD (Right eye): +0.25 → slight long-sightedness
OS (Left eye): −0.25 → slight short-sightedness
CYL (Cylinder)
This shows astigmatism (when the eye shape is not perfectly round).
Astigmatism causes blurred or distorted vision.
The number shows how strong the astigmatism correction is.
Example:
OD: −0.75
OS: −1.00
Left eye has more astigmatism than the right eye.
AXIS
This shows the direction of the astigmatism.
It is written in degrees (0–180).
Axis only works with CYL, not alone.
Example:
OD: 120°
OS: 20°
OD and OS meaning
OD = Right eye
OS = Left eye
In short:
SPH = how far or near you see
CYL = amount of astigmatism
AXIS = direction of astigmatism
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