It is obvious, but if you plan to buy prescription glasses or sunglasses online, you will need to have a copy of your optical prescription to complete the purchase. If you already have one in the house somewhere, you will have to check its current validity because the sight of the human eye tends to change with age, so the optical prescriptions have a certain validity.
Your prescription should be fine to use if:
You are under the age of 70 and your prescription was taken within the past two years or, if you are age 70 or older, your eyeglass prescription should have been taken within the past 12 months.
Note: The above validity periods are recommended by the British Association of Dispensing Opticians.
If you need a new prescription, you will need to see your local optician for an eye exam. At the time of writing, we recommend Specsavers and Tesco for offering the cheapest eye tests, but of course shop around because any licensed optician will. While you are in the eye exam, you should be sure to request the pupillary distance (PD) measurement because this measurement is a key part of getting glasses that fit perfectly. Usually this will be free, but some opticians may add a nominal service charge. While it is essential that the Varifocal and Bifocal customer have an optician take this measurement, all other customers have the option of taking their PD measurements at home if they forget to ask their optician during the eye exam:
Measuring pupillary distance at home (also known as PD):
This is the measurement in mm between the 2 pupils when looking into the distance. This number is usually written as “PD 63”, but can sometimes be written “PD 63/59”. In the last example, the first number, 63, is the measurement between the pupils for when the eyes look into the distance and the second number, 59, is the measurement for reading (or seeing things up close). The difference between the two measurements is explained by the fact that when we look at objects closely, the eyes converge and therefore the distance between the pupils narrows.
It is actually quite easy to measure your PD and all you need is a ruler and a friend to help you. As you look into the distance, ask your friend to measure from the center of the right pupil to the center of the left. It’s as simple as that.
After your eye exam, your optician is required by law to give you a written copy of your prescription. Some opticians will try to pressure you into buying glasses after your eye exam and may make excuses for not filling your prescription. This [as you’ve already guessed] It is trying to prevent you from buying your glasses elsewhere, but if you have paid for your prescription, you have the right to own them. That is the law and it is also written in the regulations of the UK General Optical Council. So if your optician doesn’t want to hand it over to you, you can politely tell him any [or even a few] of the following to loosen the prescription retention grip immediately:
1. I have paid for it, therefore it is mine and consumer protection laws dictate that you must give me my prescription in writing immediately after payment for my eye exam.
2. I need it for work – they won’t accept a receipt from the optician to pay for my eye exam.
3. My doctor wants a copy.
Deciphering your prescription:
Strictly speaking, most people will not need to understand anything written in their prescription to order glasses online, as they will only be asked to copy the details into an equivalent prescription form on the website, taking special care to ensure that the correct plus or minus sign the sign is entered online. That said, there is nothing in the recipe that is difficult for the layman to understand and some insights can make the consumer more confident in their purchases, so here we go.
All recipes contain numbers written under the flowing headings:
Dial – The number in this box indicates the strength of your prescription in 0.25 increments. A negative number here implies that you are nearsighted and a positive number indicates that you are farsighted.
Cylinder (Cyl) and Axis: The numbers in these charts are measurements of the eye’s astigmatism. (These are not applicable to all prescriptions and it is quite normal to have only one Sphere value.) The Cyl numbers represent the amount of correction needed, while the Axis numbers represent the location of the astigmatism.
Close Addition – If you are purchasing glasses specifically for reading, computer work, or intermediate range viewing, the Add or Close Addition value is the amount you should add to the value of the sphere (SPH).
Other terms that may be on your prescription include:
OD – this is Latin and means “right eye”
SO: again, this is Latin and means “left eye”.
BVD – This is the posterior vertex distance and is the distance from your eye that the lens was held when tested. Add this to additional comments.
BALANCE:
Written on prescriptions when there is little or no vision in one eye and the optician wants to make sure the lenses match weight and thickness for cosmetic reasons.
PRISMS:
Prism values are written into recipes when people slightly squint or have lazy eyes. You must enter the values of your prisms in the additional information box, with the prescription.
Note: Prisms are more expensive than regular lenses and you will need to email the website with your prescription to get a price quote for the lenses.
Visual acuity: “VA” stands for visual acuity. This represents the line of letters you can read in the table and VA values are not required to order glasses.
VA indicates the vision standard (for each eye) when corrected.
