On the prescription you receive from your ophthalmologist or optician, this is indicated by the abbreviation 'cyl'. This refers to the cylinder. This value is required for the production of spectacle lenses or contact lenses to correct so-called astigmatism.
Astigmatism describes the irregularity of the cornea (the front layer of the eye). This means that the horizontal and vertical radii are not at a 90° angle to each other, but are offset.
Astigmatism is measured in diopters and indicated with an associated axis, which is an additional correction that the eye needs. Around 40-80% of all people are affected by mild to severe astigmatism.
Cylinder value and axis value
In the case of astigmatism, the usual spherical shape of the eye is irregular. This deviation usually runs in different directions. For this reason, in the case of astigmatism, the cylinder value must always be indicated with the corresponding axis position. The direction is always given in degrees and is usually abbreviated 'A' or 'ACH' in your prescription.
It is usual to measure two different cylinders and also two different axes for each eye.
Toric lenses as opposed to spherical lenses
There are spherical lenses which are evenly curved and are used to correct short-sightedness or long-sightedness. If your astigmatism is measured, your lens design is changed from spherical to toric
The toric lens bundles the otherwise scattered rays of light into a single beam and focuses them on your retina.
This creates the sharp image that you have again thanks to the corrected astigmatism.
Arrange an eye test with us now and find out what your eyesight looks like, whether and which correction you need and let our team give you the best advice to find exactly the right lens for you!