It’s obvious, but if you plan to buy prescription glasses or sunglasses online, you’ll need to have a copy of your optical prescription to complete the purchase. If you already have one in the house somewhere, you’ll need to check its current validity because the human eye’s sight tends to change with age, so optical prescriptions have a certain shelf life.

Your prescription should be okay to use if:

You are under age 70 and your prescription was filled within the last two years or, if you are age 70 or older, your eyeglass prescription should have been filled within the last 12 months.

Note: The above validity periods are recommended by the Association of British Dispensing Opticians.

If you need a new prescription, you will need to go to your local optician for an eye exam. At the time of writing, we recommend Specsavers and Tesco for offering the cheapest eye tests, but shop around because any licensed optician will do. During your eye exam, you should be sure to request a pupillary distance (PD) measurement, as this measurement is a key part of getting the best fitting eyeglasses. This will usually be free, but some opticians may add a nominal service charge. While it is essential for the Varifocal and Bifocal client to have this measurement taken by an optician, all other clients have the option of taking their PD measurements at home if they forget to ask their optician during their eye exam:

Home pupillary distance measurement (also known as PD):

This is the measurement in mm between the 2 pupils when looking far away. This figure is usually written as “PD 63”, but can sometimes be written as “PD 63/59”. In the last example, the first number, 63, is the measurement between the pupils when the eyes look far away, 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 up close, the eyes converge and therefore the distance between the pupils narrows.

It’s 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 delivering your prescription. East [as you’ve already guessed] is to try to prevent you from buying your glasses elsewhere, but if you have paid for your prescription, you have the right to own it. That is the law and it is also written in the UK General Optical Council regulations. So if your optician doesn’t want to give it to you, you can politely say any [or even a few] of the following to loosen that recipe-holding grip right away:

1. I have paid for it, so 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.

Cracking your recipe:

Strictly speaking, most people will not need to understand anything that is written on their prescription to order glasses online, as they will only be required to copy the details onto an equivalent prescription form on the website, taking special care to make sure the correct plus or minus sign is entered online. That said, there is nothing in the prescription that is difficult for the layman to understand and some knowledge can make the consumer more confident in their purchases, so here we go.

All recipes contain numbers written below the flowing headings:

Dial: The number in this box indicates the strength of your recipe in 0.25 increments. A negative number here implies that you are myopic and a positive number indicates that you are myopic.

Cylinder (Cyl) and Axis: The numbers in these boxes 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.

Near Add: If you’re buying glasses specifically for reading, computer work, or mid-range viewing, the Add or Near Add value is the amount you should add to the dial value (SPH).

Other terms that may be found on your prescription include:

OD – this is Latin and means “right eye”

OS – again this is Latin and means “left eye”

BVD – This is the posterior vertex distance and is the distance from the eye where the lens was held when the test was performed. Please 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 are matched in weight and thickness for cosmetic reasons.

PRISMS:

Prism values ​​are written in prescriptions when people have a slight squint or lazy eye. You must enter the values ​​of your prisms in the additional information box, with the recipe.

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 on the chart and VA values ​​are not required to order glasses.

VA indicates the vision standard (for each eye) when it is correct.