A prescription is an important written document given by a qualified optometrist or suitably qualified medical practitioner, outlining a specific treatment.

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.

Where can I get my prescription from

Your prescription will be registered at any optometrist or optician or eye practice where you have had an eye exam and shows the health of the eye and recommends the strength of the lens you need in order to see clearly.

In most instances, you will be given a copy of your prescription after the exam, but in the event that you are not, you can always request one. It is a legal requirement to provide you with your prescription for glasses or contact lenses upon request- by law you should always receive a copy of your prescription.

I cant find my prescription 

If you’ve misplaced your prescription, you’ll need to call or visit your local optician who will provide a copy of your prescription which can then be relayed to us.