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Glasses Guide – Buying Glasses Online

Before buying glasses online from us we recommend reading our simple guide to buying glasses online. This glasses guide will help you to understand what your prescription means and how to choose a frame that will both suit and fit your face comfortably. We have also provided additional links for individual topics if you would like more detailed information.

Buying Glasses Online, is it Safe?

Absolutely. Buying glasses online is as safe as buying any other product online providing the item is purchased from a reputable and trusted retailer. Understandably, buying tailored items such as prescription glasses online is slightly different to a standard ‘off the shelf’ product, but SelectSpecs.com can assure you that our products are supplied to the highest standard. If you are worried about using a credit card online with us, please don't be, your payments are processed through secure payment merchants, SelectSpecs.com do not store your credit card information. We also accept payments by cheque (UK only) or through well known payment systems such as PayPal.

All incoming orders for prescription spectacles are checked and you will be advised if there are any obvious discrepancies in your prescription. All outgoing prescription spectacles are also thoroughly checked by our quality control staff who ensure that your glasses have been made to the required prescription and to the highest standard.

SelectSpecs.com have been providing high quality glasses since 2005 to 1000’s of new and returning customers every year! Why not see what our customers have to say about us by viewing reviews from real customers submitted to Trust Pilot here.

Getting and Understanding your Prescription

In order to buy prescription glasses from SelectSpecs.com you will need your prescription, if you do not have a prescription you either do not need glasses or you haven’t had your eyes tested recently. If you have not had your eyes tested in the past 2 years then we highly recommend visiting your local optician for a check up, not only will this test tell you if you require glasses but it also acts as a general health check.

Get your Prescription

You have just had your eyes tested but your optician won’t give you a copy of your prescription for fear of you not buying glasses from them?

Under the UK Opticians Act of 1989, it is the obligation of any optician to provide you with a prescription. The optician will provide you with a thorough eye examination and is then required by Law to provide you with a copy of your prescription for your own records.

Understanding your Prescription

IMPORTANT - A very common mistake!
The most common mistake we see on an almost daily basis is the wrong selection of "+" and "-" values when entering prescriptions online. We cannot stress enough that extra care must be taken when selecting these values!

At first glance, especially for a new glasses wearer, your glasses prescription can look confusing but it is actually quite simple to understand. This is how your prescription will generally be laid out (depending on country):

Lets look to see what each of these measurements mean.

SPH / Sphere

The sphere (Sph) specifies the strength of lens required to correct your focus - a plus sphere to correct long-sightedness (hyperopic - difficulty focusing on close objects) and a minus to correct short sightedness (myopia - difficulty focusing on distant objects.)

The sphere is measured in Dioptre’s, your prescription may have the word Plano or Pl or an infinity sign, this means that you are neither long nor short sighted but zero power for the Sphere. Most values range from 0.00 to +/- 20.00 and go up in steps of 0.25.

CYL / Cylinder

The CYL and AXIS compensate for an astigmatism. So what's an astigmatism? An astigmatism is where the eye is shaped slightly like a rugby ball or referred to as ‘toric’, not a perfect sphere like a football. This just means the eye has difficulty focusing at certain angles.

This box maybe empty or have a plus or a minus value in it. The measurement is the Dioptre. Most values range from +/- 0.25 to +/- 4.00 and will go up in steps of 0.25.


The AXIS is only present if there is a value in the CYL box, the AXIS tells us where the astigmatism is on your eye. The measurement is in Degrees. The values range between 0 and 180 and may go up in steps of ½, 1, 5 or 10 degrees, we only show the AXIS to a whole number but if you have a ½ degree on your prescription you can list this in the additional information box when ordering.

ADD / Addition

The Add, short for Reading Addition, is the additional correction required for reading, this can be used to make either reading glasses, bifocal glasses or Varifocal glasses.

This figure is an indication of how much extra power is required ‘on top’ of the distance prescription for near or intermediate glasses. This extra power will ALWAYS be the same for each eye and may only appear once on your prescription but it is understood to be meant for both eyes. The measurement is the Dioptre, and most values range from +0.50 to +3.50 and will go up in steps of 0.25.

The 'addition' is only required if the glasses are going to be used for reading or close work. If your glasses are for distance only, this will not be an issue. Sometimes opticians use the word 'Add' or 'Near' instead of 'addition'. They may only write it once, but it normally applies to both eyes and is almost always the same value for both eyes (e.g. 'Add' +2.50 - should be entered for both eyes).


A Prism is to try and correct a lazy eye and indicates a more delicate condition, this is included with a prescription to correct some special conditions or some eye disorders (like squints) that require the focussed image to move position. The measurement is Prism Dioptre. The value may be as high as 10 and may go up in steps of ½ or 1 Prism Dioptre's.

If your prescription contains a prism, kindly contact us with your full prescription, we may be able to add this to your prescription for a small additional fee.

Remember, if you are still unsure of your prescription you can easily fax, post or email a copy to us when you place your order.

How to Check your PD (Pupillary Distance)

You can contact your optician for this measurement or if you have a spare pair of spectacles please send them to us together with a print out of your order, we will record the pupillary distance measurement from these to ensure accurate centration of your lenses. We will post your Spectacles back to you with your completed spectacles.

On average the PD in an adult is usually between 60 and 66 millimetres. You are welcome to leave the Pupillary Distance (PD) at 63mm when entering your prescription however it Is advised to get this from your optician or from previous spectacles, alternatively you can measure your pupillary distance (PD) yourself using the instructions here.

You can also purchase a PD ruler from us for a very small charge, click here to find out more.

Choosing the Correct Frame Style to Suit your Face

Choosing new Spectacles can be a long process, and ultimately can make an enormous impact on the way you look. Spectacles are no longer seen as a device to aid your vision, in this constantly growing fashion conscious world we live in, they are a reflection of your personal image or a decorative piece of jewellery to enhance your facial features.

We have written a separate guide to face shapes that you may find useful, click here to read more..

Understanding Different Frame Sizes

The lens size is the width across the widest part of the lens (in mm). The bridge size is the width of the nose bridge. The arm length is the length of each arm. These sizes can usually be found on your current glasses by looking on the inside of the frame (usually the arms or the bridge). For example, a frame with the following measurements 52-16-135 will be as follows:

  • 52 = 52mm Lens Width
  • 16 = 16mm Bridge Size
  • 135 = 135mm Arm Length

We have written a separate guide to understanding frame measurements that you may find useful, click here to read more.

Why you Should Choose Thin Lenses

Standard lenses are perfectly suitable for low prescriptions but for those with higher prescriptions standard lenses tend to be thicker and heavier making them unattractive and uncomfortable to wear. For those with higher prescriptions we like to recommend customers choose a High Index/Thin lens as they are lighter on the nose and more attractive, making glasses much more comfortable to wear.

As a rough guide, we recommend...

1.49 Index
For prescriptions with Sphere values from Plano to +/- 3.00

1.56 Index
For prescriptions with Sphere values from +/- 3.00 to +/- 3.75

1.61 Index
For prescriptions with Sphere values around +/- 4.00

1.67 or 1.74 Index
For prescriptions with Sphere values above +/- 4.25 it would be ideal for 1.67 or 1.74 index.

With any plus powers above +3.00, we recommend our 1.67 or 1.74 lenses because these lenses are Aspheric in design, this means the lenses are made not only thinner but flatter than a standard spherical lens, this reduces magnification of your eyes to anyone who looks at you, and of course the lenses are lighter as a result.

Understanding the Different Lens Coatings Available

We include UV Protection, Scratch Resistance, and Anti-Reflection FREE as standard, but what do these coatings do?

UV Protection
UV or Ultraviolet light is found in sunlight and can be damaging to the eye and may lead to cataracts, pterygium and pinguecula formation. A UV coating on your glasses stops the UV light from penetrating the lens and potentially damaging your eyes.

Scratch Resistance
Scratch-Resistant is a hard and clear coating that helps to prevent minor scratches that may occur from day to day wear meaning the life of the lens will be extended helping you to enjoy clearer vision for longer.

An anti-reflective coating will eliminate surface reflections on a lens that will increase light transmission through the lenses providing you with clear defined vision night or day. This coating is recommended for computer use and night-time driving.

For more information about lens coatings please click here.

Ordering your Glasses from SelectSpecs

Ordering from our website should be a simple and painless process.

How can I pay for my order?
We accept all major credit and debit cards, PayPal, and cheque payments drawn on a UK bank account, VAT is included for customers in the UK and within the EU.

How long before my order arrives?
After your glasses have been constructed in our laboratory they are posted directly to you and will take on average 10 working days. Prescription Sunglasses may take anywhere from 1-4 weeks to complete, due to specialised glazing and of course depending on frame availability.

For more information about delivery times, please see here.

How do our Prices Compare with the High Street and Online Competitors?

We are totally committed to providing our customers with a high quality product for an extremely competitive price without cutting corners. While many high street and online competitors may display a very attractive price for their products, the cost for the final product can often increase substantially after adding optional yet highly recommended lens coatings such as UV Protection and Anti-Reflection. At SelectSpecs.com we offer these coatings for free as standard!