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How do I read my glasses prescription?
Medically reviewed by Tina Patel on 10 October 2022
- What do the symbols on my prescription mean?
- Most common prescription layouts from opticians
- Can I use my glasses prescription for contact lenses?
- What is the difference between single vision and multifocal prescriptions?
- What types of lenses are there?
- Does FGC accommodate lenses for all prescriptions
After an eye examination, your optician will give you a copy of your prescription. By UK law, they are required to give this information to you and if they haven’t, you should ask for it. Once you are given your prescription, it can be difficult to understand what the words and numbers mean. We've broken down the different parts of your prescription to make things easier.
What do the symbols on my prescription mean?
+ or - Sphere (SPH)
You will see a + or – sign followed by a number. This is the SPHERE value.
'+' means you are long-sighted.
'-' means you are short-sighted
Sometimes you may find the + or - sign is written above the number. The sphere value is measured in dioptres (D), going up in steps of 0.25.
Sometimes you'll notice there is Plano, PL Infinity (∞) or 0.00, which all equal to zero. This means there is no spherical correct.
ADD
This is the additional correction required for reading. Also written as near addition, near add or NV - it is required for reading. This value is added to the sphere to calculate your near vision prescription.
An ADD can range from +0.25 to +3.50. (It goes up in steps of 0.25).
Cylinder (CYL)
Cylinder number refers to the level of astigmatism and it can start as small as +/-0.25 for spectacle prescriptions.
An empty box or DS means there is no astigmatism.
OS and OD
OS means left eye and OD means right eye.
AXIS
Axis indicates the position of the cyl and can range between 1-180 for spectacle prescriptions.
Prism
This shows if you have a muscle imbalance in your eye and is prescribed to prevent headaches or double vision.
The amount of prism is recorded in dioptres and can be written in decimal form or sometimes as a fraction and will always have a direction. (For example, 1.50D Base UP).
PD (pupillary distance)
Measures the distance between your eyes, from the centre point of one pupil to the other.
In most cases your optician will not add this to your prescription.
Other symbols
Other symbols which you may find include BAL (balance), VA (visual acuity) and BVD (back vertex distance).
VA and BVD will not be required to place your order.
General top tips for entering your prescription
- Don’t mix up + and – values when you enter you sph or cyl value
- Axis value should be entered exactly as it appears on the prescription – don’t enter 15.5 if stated 155 on prescription
- Reading glasses: don’t forget the ADD (Near Add, NV Add) if there is one stated
- Computer glasses: you may find an Intermediate Add (Inter Add or Int Add) this should be included if you intend to use your new glasses for computer use only.
Most common prescription layouts from opticians
The examples below show various prescriptions from opticians alongside examples of how these prescriptions should look when entered on our website.
Specsavers
This prescription would be entered on our website as follows:
Please note: The ADD value (Near-ADD and Inter-ADD) won't always be mentioned on your prescription, in this case please leave it blank when you enter your prescription on our website.
Sometimes the Near Add and Intermediate (Inter) Add will be worked into the prescription rather than being displayed separately.
In this example, the full intermediate and reading prescriptions have been provided.
To order glasses for computer, please enter the full intermediate prescription. To order glasses for reading, please enter the full near prescription.
Specsavers
This prescription would be entered on our website as follows:
Please note: You do not need to enter the BVD value if it is mentioned on your prescription.
Specsavers
This prescription would be entered on our website as follows:
If you are entering a prescription for distance, the Add does not need to be entered.
On occasions, your opticians may not write Sphere (sph) Cylinder (cyl) or Axis on your prescription.
Vision Express
This prescription would be entered on our website as follows:
Please note: If you would like to order glasses only for distance vision you do not need to enter the ADD value.
Boots
This prescription would be entered on our website as follows:
Please note: You do not need to enter the Distance acuity and Near acuity if it is mentioned on your prescription.
Hospital
This prescription would be entered on our website as follows:
NHS
This prescription would be entered on our website as follows:
NHS Scotland
This prescription would be entered on our website as follows:
Please note: The cylinder (CYL) value is written in a plus (+) format, make sure to select plus (+) instead of minus (-).
David Clulow
This prescription would be entered on our website as follows:
Please note: If you would like to order glasses for distance you do not need to enter the ADD value.
Other symbols
You might also find the following symbols on your prescription:
Balance or BAL
Balance or bal refers to the prescription in that particular eye and means that no values are needed for that eye. The lens for this eye is made to the same weight so that the glasses feel balanced when you are wearing them.
Here is an example of how balance would look on a prescription besides how it would be entered on our website:
Please note: If you would like to order glasses for distance vision only, you do not need to enter the ADD value.
DS
DS stands for dioptre sphere, which means a spherical correction. If this is left blank, then there is no astigmatism (cylinder and axis) that requires correcting.
Dixon Hempenstall Opticians
This prescription would be entered on our website as follows:
Plano, PL, ∞
Plano, sometimes referred to as PL or the infinity symbol (∞), means that no visual correction is required for that particular part of the prescription.
You may also find these under the sphere section.
Here is an example of how Plano would look on a prescription and beside it is how it would be entered on our website:
Please note: If you would like to order glasses for distance vision only, you do not need to enter the ADD value.
Can I use my glasses prescription for contact lenses?
The prescription you are given for your glasses and the one you are given for your contact lenses are different. They should not be used interchangeably as contact lenses sit on the surface of the eye and glasses are flatter and sit further away.
If you’re looking for help, check our guide on reading your contact lens prescription.
What types of spectacle lenses are there?
Depending on how your vision needs to be corrected, you will be recommended a certain type of spectacle lens. The types of spectacle lenses include:
- Single vision lenses, these have one power across the whole lens and are used to correct short-sightedness (myopia), long-sightedness (hyperopia) and astigmatism
- Bifocal lenses contain two different prescriptions within the lens and are used to see objects both near and far away.
- Progressive lenses or varifocal lenses also known as multifocal lenses, are lenses which have three prescriptions merged within one lens and are used for near vision (e.g. reading a book), intermediate vision (e.g. looking at computer screen) and distance viewing (e.g. driving)
Take a look at our article for more information on the various lens types.
Does FGC accommodate lenses for all prescriptions?
We do a wide variety of prescription, however, we are unable to do very strong or very high prescriptions. The prescriptions we cater for are as follows:
Up to and including -8 sphere power and up to and including –4 cylinder power
Up to and including -8 sphere power and up to and including +4 cylinder power
Up to and including +8 sphere power and up to and including –4 cylinder power
For + cylinder powers, we can cater for any combination up to +4 sphere and +4 cylinder (combined prescription of +8)
Please also note, currently we offer single vision lenses only.
You should now have a better understanding of what your eyeglass prescription means which will help you select the right optical glasses for you and your visual requirements.
If you have any questions regarding your prescription and choosing the right optical glasses for you, please do not hesitate to contact our helpful optical team by calling 01 514 3614 (Free) or emailing cs@feelgoodcontacts.ie
