Opticampare
Read your prescription.
Prescriptions look different from country to country, but they use the same terms. Here is what each one means.
| SPH | CYL | Axis | ADD | |
|---|---|---|---|---|
| OD (right) | -2.00 | -0.50 | 90 | +1.50 |
| OS (left) | -2.25 | – | – | +1.50 |
OD and OS
OD is your right eye, OS is your left. Some prescriptions write R and L instead.
SPH (sphere)
Your main lens strength. Minus means short-sighted (far things are blurry), plus means long-sighted.
CYL and Axis
Correct astigmatism. Axis is a number from 1 to 180 and only appears when there is a CYL value. Copy both exactly.
ADD
Extra strength for reading, usually for people over 40. If you have an ADD, you may want progressive lenses or separate reading glasses.
PD
The distance between your pupils in millimetres. If it is not on your prescription, measure it with the PD tool.
Lens thickness (index)
A higher index means a thinner, lighter lens. Stronger prescriptions benefit most: above ±4.00, thin lenses make a clear difference.
Is it still valid?
Prescriptions usually expire after one to two years. Many shops ask for a valid one, and an eye exam also checks your eye health.