To find the best fit for your glasses, first you should look for the perfect frame width.
A frame that’s slightly wider than your face is a good place to start — no more than a finger width between the temple and your face is a good rule of thumb.
OD (Oculus Dexter): Your right eye prescription.
OS (Oculus Sinister): Your left eye prescription.
SPH (Sphere): Main vision correction.
- A negative number (–) means nearsightedness.
- A positive number (+) means farsightedness.
CYL (Cylinder): Astigmatism correction (usually a negative number like –0.75). A CYL value will always have an Axis value.
AXIS: Angle for astigmatism (1°to 180°), telling where the astigmatism correction is applied..