What does my eye prescription mean?
Published: 21/02/24 By: Ellie Senior
Almost 60%* of the UK population wear glasses today and most people will need help to correct their eyesight in later years.
To understand your glasses prescription fully would take many years of training. But just as you don’t need to understand how your car works in order to drive it, thankfully this level of expertise isn’t necessary. Instead, build trust and rapport with your chosen Optometrist and let them be your guide.
Understanding your prescription
A glasses (or contact lens) prescription corrects a refractive error in your sight so that your eyes don’t have to work so hard. Refractive errors cause your vision to blur because the eye doesn’t bend light as it should. There are four main types of refractive error and each can be corrected using different aspects of your lenses.
SPH (Spherical error)
The measure of how long or short sighted you are.
- – value means you are shortsighted and have difficulty seeing things in the distance
- + value means you are longsighted and struggle to see things up close
There is no set value at which you definitely need to wear glasses because each of us adapt differently, but the higher the number the more likely you are to experience symptoms such as blurred vision, headaches, migraines and fatigue. A number higher than 2 means you’re likely to find it difficult to drive safely, while a value over 5 puts you at higher risk of health conditions.
CYL (Cylindrical power) and AXIS
The measure of how much astigmatism you have (which is how rugby ball shaped your eye is) and the direction this is at.
- This component is added to your lenses to help you see more clearly both far and near
- The CYL number shows the severity of your astigmatism
- The AXIS value puts this element of your prescription at the correct angle for you
The three-dimensional nature of an astigmatism makes this a more complex prescription. It must be precisely followed to build lenses that work for you.
PRISM (Prismatic power) and BASE
The correction needed when your eyes struggle to work together, such as if you have a squint.
- Prism takes the strain your muscles would otherwise be under to keep your eyes parallel
- Base shows the direction this is needed; up, down, in or out
This is a less common refractive error than the others but is still frequently seen by our team. Our Optometrists take time to look at carefully at this layer of detail, as it results in a constant niggling tension if not corrected.
ADD
The additional correction you might need for reading, typically as you get older.
- From your late 40s your eyes become less able to adapt between focusing near and far
- This will be added to bifocal or varifocal lenses to give the magnification needed for close tasks
CLRX (Contact Lenses)
The additional details needed if you choose to use contact lenses.
- TYPE is the brand chosen
- BC is the base curve which ensures the lenses fit the curve of your eye
- DIAM is the size of lens you need in diameter
A contact lens sits approx. 1cm closer to your eye than a pair of glasses. Your Optometrist will alter each element of your prescription to account for this and make sure your lenses fit your needs.
Can I use my prescription to buy glasses or contact lenses online?
For most people, it’s best to buy your glasses in the same place you had your sight test. Your prescription is made up of a number of complex factors and the glasses will need to be built to cater exactly for your needs.
At Spectacular Opticians, your Optometrist and Dispenser work closely together to make sure your prescription, the frame you’ve chosen and your measurements work together to keep your eyes happy.
Off-the-peg spectacles from the chemist or glasses ordered online will work for a small number of people who need minimal optical support. A more bespoke service is best if you have a high prescription, require varifocals, experience any differences between each eye or are affected by a number of other common complexities.
The College of Optometrists found that glasses purchased online are twice as likely to fail and cause much greater risk of complications. At Spectacular Opticians we make sure your glasses or contact lenses are tailored to suit your personal imperfections and imbalances, preventing the uncomfortable symptoms you get when your eyes are left to do the work.
Visit our expert team at your nearest practice today to experience the care and attention we give to dispensing an eye prescription tailored exactly to your needs.
Categories: Eye examinations, Glasses, Vision
