UNDERSTANDING CONTACT LENS PRESCRIPTION
How do I read my prescription?
A typical contact lens prescription looks like this:
Right: 8.60/ 14.00/ -2.50 (BRAND A)
Left: 8.60/ 14.00/ -3.00 (BRAND A)
Where the:
Base Curve (BC) is 8.60 mm
Diameter (Dia) is 14.00 mm
Power (Sphere) is -2.50 dioptres
BRAND A refers to the exact Lens type & Brand prescribed
BC (Base Curve):
Refers to the shape of the curve of your contact lens
(Usually a number between 8.0 and 10.0)
DIA (Diameter):
Refers to the size of lens that is recommended to fit your eye
(A number between 13.00 and 15.00)
Power (Sphere):
Refers to the strength of your contact lens
(A number between -20.00 and +20.00)
Cylinder (CYL) (Toric Lenses Only):
Refers to the strength of your astigmatism
(A number up to -4.00)
Axis (Toric Lenses Only):
Refers to the location of your astigmatism
(A number between 0 and 180)
If you have a prescription for spectacles, it will look very similar to a prescription for contact lenses, but the numbers are not interchangeable. For further information see below "Is my prescription the same for both specs and contact lenses?" If you are unsure about your prescription, please contact our Customer Support team on 0207 323 9704, or email optician@onestopcontactlenses.co.uk
Right: 8.60/ 14.00/ -2.50 (BRAND A)
Left: 8.60/ 14.00/ -3.00 (BRAND A)
Where the:
Base Curve (BC) is 8.60 mm
Diameter (Dia) is 14.00 mm
Power (Sphere) is -2.50 dioptres
BRAND A refers to the exact Lens type & Brand prescribed
BC (Base Curve):
Refers to the shape of the curve of your contact lens
(Usually a number between 8.0 and 10.0)
DIA (Diameter):
Refers to the size of lens that is recommended to fit your eye
(A number between 13.00 and 15.00)
Power (Sphere):
Refers to the strength of your contact lens
(A number between -20.00 and +20.00)
Cylinder (CYL) (Toric Lenses Only):
Refers to the strength of your astigmatism
(A number up to -4.00)
Axis (Toric Lenses Only):
Refers to the location of your astigmatism
(A number between 0 and 180)
If you have a prescription for spectacles, it will look very similar to a prescription for contact lenses, but the numbers are not interchangeable. For further information see below "Is my prescription the same for both specs and contact lenses?" If you are unsure about your prescription, please contact our Customer Support team on 0207 323 9704, or email optician@onestopcontactlenses.co.uk
Why do you require my contact lens prescription?
Under UK law, we have to have a current contact lens prescription (< 1 year old) in order to supply replacement contact lenses. A contact lens prescription is similar to a spectacle prescription. It does, however, contain specific contact lens related information. The prescription will state the brand of lenses for which you have been fitted and the size and strength of the lenses. The prescription will be dated and signed by your optician. A prescription is not valid if it has not been signed and dated.
Why can't I send the contact lenses packets?
The packets will confirm the brand of lenses that you wear. However, we still need to see a valid copy of your written prescription signed and dated by your eyecare practitioner.
Is my prescription the same for both specs and contact lenses?
No. A contact lens prescription is only 100% complete when the details of their fit are included. This means that although the powers may seem similar to your spectacle prescription, the powers alone are not sufficient when specifying a contact lens prescription. Additional parameters like lens type, diameter and base curve must also be included.
Example 1:
Mr Seewell's Spectacle prescription is:
R) - 6.50
L) - 6.00/-0.25 x 180
However his contact lens prescription is:
R) 8.60/14.20/-6.00/Focus
L) 8.90/14.20/-5.50/Focus
Example 2:
Mrs Sheng's Spectacle prescription is:
R) +4.50
L)+2.50/-1.00 x 90
Her contact lens prescription is:
R)8.80/14.20/+4.75/Frequency 55
L)8.70/14.40/+2.50/-0.75 x 90/Excel Toric
A contact lens specification is normally written in the above format denoting:
Base curve/diameter/power/lens type
Example 1:
Mr Seewell's Spectacle prescription is:
R) - 6.50
L) - 6.00/-0.25 x 180
However his contact lens prescription is:
R) 8.60/14.20/-6.00/Focus
L) 8.90/14.20/-5.50/Focus
Example 2:
Mrs Sheng's Spectacle prescription is:
R) +4.50
L)+2.50/-1.00 x 90
Her contact lens prescription is:
R)8.80/14.20/+4.75/Frequency 55
L)8.70/14.40/+2.50/-0.75 x 90/Excel Toric
A contact lens specification is normally written in the above format denoting:
Base curve/diameter/power/lens type
