and how to read them.
If you need glasses, your optometrist will provide you with a prescription full of different values needed to construct the right lenses for you. In other words, your prescription contains the ‘specs’ (wink, wink) you need to get yourself some proper lenses.
Understanding your prescription can be a real hassle. We’re going to simplify it, so all you have to worry about is finding the right set of frames.
When we measure your prescription we look into four values: Sphere (SPH), Cylinder (CYL), Axis (AXI) and Pupillary Distance (PD).
The SPH number corrects for myopia or hyperopia (-/+). The CYL and AXI numbers correct for astigmatism. Have we lost you? Don’t worry, we’ll go into these technical terms a bit later.
Lastly, Pupillary Distance (PD) is, you guessed it, the distance between your pupil and your nose. It determines where the optical centre of the lens will be for clear, accurate vision. If you can’t find the PD on your prescription, pop by one of our stores to have it measured, or ask your optician.
It’s really important to have all this information when ordering prescription glasses. If you’re unsure about anything, you can have your eyes tested by us for free. Prescriptions usually expire after 1-2 years, so if it’s been a while since you last saw your optician, book yourself in for a check up.
It’s handy to know that you can’t use your contact lens prescription when ordering new glasses, since they require different measurements.
Ok, so far almost so good... but what are myopia, hyperopia and astigmatism?
Myopia is commonly known as nearsightedness. People with myopia can typically see well enough to read a book and look at a computer screen, but struggle to see objects from far away. It’s caused by the eye being too long from front to back, so the eye lens doesn’t focus images on the retina (the light-sensitive tissue in the back of the eye), but in front of it. It can lead to headaches and eyestrain. Myopia is indicated with a minus (-) on your prescription.
Hyperopia, known as farsightedness, is a common type of refractive error where distant objects can be seen more clearly than objects that are close by. People can experience hyperopia in different ways - some people don’t even notice it, especially when they’re young. For those with significant hyperopia, objects can look blurry at any distance. Hyperopia is indicated with a plus (+) on your prescription.
Astigmatism is a common condition that causes blurred vision. It occurs when the cornea (the clear layer that forms the front of the eye) is irregularly shaped, or sometimes due to the curvature of the lens inside the eye.
Now that you’re prescription-savvy, you can go and get some of our glasses!