Vision Types
There various vision types which can categories a human eye. The ones which are important for optical prescription glasses include single vision, Multifocal, VDU.
Single vision lenses have one dioptric power throughout the entire lens. They can be used to correct vision in either near or far viewing situations, which is why single vision lenses form the basis of both distance glasses and reading glasses.
In the same way that prescriptions for glasses and contact lenses are different, so are prescriptions for single vision and multifocal prescriptions. Multifocal prescriptions include Bifocal and Varifocals; they are made up of two or more prescriptions (one for distance and one for reading), so you can expect your prescription to look different.
Bifocal lenses consists of one section that corrects for distant vision and another section that corrects for near vision.
Varifocal or progressive lenses, have a gradual change in strength from the top of the lens to the bottom with multiple focal points in between. This allows you to see all distances and focus points through just one lens.
VDU lenses are specially designed for working at a screen, enabling problem-free vision at a computer workstation.
Where can I find my glasses prescription?
Your prescription would usually be provided by your optician after your eye exam in either paper or digital format. If you cannot locate your prescription don’t worry you can still purchase your order. Click the ‘Enter Prescription Later’ option when selecting you lens on the product page. We’ll send you a follow up email to check if you have your prescription. If you’ve misplaced your prescription, you’ll need to call or visit your local optician who will inform you of your prescription which can then be relayed to us. If you need any assistance during this process, don’t hesitate to contact us.
Understanding my prescription?
Apart from your name and date of birth, you will notice that there are quite a few letters, numbers and symbols on your prescription. This is what they all mean:
‘+’ – Shows if you are long sighted (longsightedness)
‘-‘ – Shows if you are short sighted (shortsightedness)
SPH
This shows how strong the correction needs to be. A ‘-‘ symbol above the number indicates shortsightedness whereas a ‘+’ symbol indicates longsightedness. Other symbols that can be found in this section are the infinity symbol (which looks like a sideways eight) or the word Plano (or Pl), which are the equivalent of ‘zero’ and are used when no sight correction is required. Another common term that can be found on prescriptions is V/A (or visual acuity) which measures the standard of vision when corrected.
CYL
This shows how much astigmatism you have and the number can be negative or positive. Astigmatism is when the front part of your eye is shaped more like a rugby ball than a regular circle. If you don’t have an astigmatism, there will be no figures written in the cylinder and axis boxes.
Axis
This shows the position of the cylinder. It will be between 1 and 180.
PD and Pupillary Distance
This is the distance between your eyes measured between your pupil centre points. Usually, the optician will not add this to your prescription, so you should ask for it as it’s important for those with high-strength prescriptions to have lenses that are centred more accurately. To ask for your PD, you can tell your optician that you will be purchasing an item they do not stock, such as prescription goggles online.
Add
This will indicate if you need a prescription for reading and is applied to bifocal and varifocal lenses to correct presbyopia. You may also have an Inter Add for computers or other tasks like reading music on a stand.
Prism
This shows if you have a muscle imbalance in your eye. It’s less common to see this box filled in as it’s fairly rare. The prism is usually written in fractions (for example 1 ½).
Base
This shows the direction of the prism in your lens, for example IN, OUT, UP or DOWN. This is fairly uncommon so the boxes are normally empty.
How to enter my prescription on Specstown?
After following steps to select your lenses and package, you’ll be given three options for sharing your prescription with us: "send prescription later", "enter new prescription", or "use saved prescription". If you’ve shopped with us before and your prescription is up to date (more on that in a second), then select "use saved prescription".
If you’re new to Specstown (or have a new prescription) and have your prescription on hand, then select "enter new prescription". If you’re in need of a new prescription, select "send prescription later". This option allows you to send your prescription via photo, email, phone or post after you’ve placed your order.
Before submitting your prescription to us, you must make sure it is up to date and was given to you within the last two years. Experts advise having your eyes tested at least once every two years. Prescription older than that? Make sure you get your eyes tested soon.
I cant enter my prescription because its too high?
Please note that we are unable to fulfil some prescriptions. Orders for very strong prescriptions are excluded, such as when the combined SPH and CYL is greater than +/-8.00, when the CYL is over +/-4.00, if there is more than a 5.00D difference between each eye or if the prism correction is over 4.00 in any direction. Orders for prescriptions with a combined SPH and CYL of more than +/- 8.00 can currently also only be placed over the phone.
What if my prescription is wrong?
A prescription issued by a certified optician should generally be correct, but sometimes there can still be problems with the glasses made from it.
One issue could be that the numbers haven’t been submitted correctly. You can find this out by checking the prescription you were given by the optician against the specification we have sent to you. Or maybe the numbers match but it still doesn't feel quite right. If this is the case, your prescription could still be correct, it’s just most new prescriptions take a little while to get used to. If you are still having problems after 2-3 days, contact us and one of our highly trained Clinicians will advise you.
