On the prescription you get from your ophthalmologist or optician, this is listed with the abbreviation 'cyl'. Written out, this means the cylinder. This value is required for the production of glasses or contact lenses to correct a so-called astigmatism.
Astigmatism describes an irregularity in 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 given with an associated axis, this is an additional correction that the eye needs. Approximately 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 specified with the associated axis position. The direction is always given in degrees and usually has the abbreviation 'A' or 'ACH' in your recipe.
It is common that two different cylinders and also two different axes are measured for each eye.
Toric lenses versus spherical lenses
There are spherical glasses, these are evenly curved and are used to correct nearsightedness or farsightedness. If your astigmatism is measured, your lens design will be changed from spherical to toric
The otherwise scattered light rays are bundled through the toric glass and reproduced as a focal point 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 how you look, whether and which correction you need and let our team give you the best advice to find exactly the right lens for you!