Your eye test explained

Your eye test and prescription can be confusing, especially if you’ve never worn glasses or contact lenses before. Read our guide to get your eye test and eye prescriptions explained.

All of our Opticians have trained for a minimum of four years in order to qualify and are continually updating their skills and qualifications. All our eye tests are designed to check not only your prescription, but the health of your eyes and also to spot any possible eye conditions that may require further investigation.

Depending on your age and family history, your Optician may also carry out checks for conditions such as glaucoma and diabetes. To find out how short or long sighted you are, your Optician will run a number of tests, including asking you to read letters and words, with the print becoming smaller and smaller.

They will also test whether one eye is stronger than the other, and try a range of different powered lenses to see what correction you require.

During your eye test they will also examine the back of the eye to find out how healthy your eyes are and spot any potential problems. If you have any questions during your eye test, your Optician will be happy to answer them.

Your eye prescription explained

The Sphere (Sph)
This indicates the power of the lens that is needed to correct your sight.
A minus power ( – ) is prescribed if you are short sighted
A positive power (+) is prescribed if you are long sighted

The strength of lens is indicated by the numerical value; lens power is given in 0.25 steps, the higher the value the stronger the lens required.

The Cylinder (Cyl)
Cylinders or Cyls are prescribed to correct Astigmatism. Astigmatism relates to the shape of the front of the eyes, as the eye can be shaped like a rugby ball as opposed to spherical like a football; the rugby ball shape can cause vision to be distorted. Cylinders help to correct astigmatism by providing further power across one area of the lens.

Axis
The axis is linked to the cyl as it indicates its position. It enables the cylinder to be placed in the correct position when the lens is mounted into a frame.

Near vision add
The near vision add is an amount of power which when added to the distance prescription will provide clear vision whilst looking at something within an arms length range.

Intermediate add
The intermediate add is an amount of power which when added to the distance prescription will provide clear vision whilst looking at a mid range – computer screen for example.

Prism
Prisms are prescribed to help the eye muscles and reduce the feeling of eye strain or double vision (if present). Prisms help the eyes to work together.

Base
The base is the direction that the prism will be placed when the lens is being made.