Toric Contacts: What is Cylindrical Power?
Cylindrical power in your prescription simply indicates your eye doctor has detected astigmatism that is caused by an irregular shape of the cornea. CYL value always comes with an AXIS value that is the degree of the angle of the CYL. Astigmatism is so common that almost all of us have some degree of astigmatism that usually needs no correction. Fortunately unlike myopia, Astigmatism is not progressive but stable. Wearing specialised glasses or Toric contacts help you see clearly with Astigmatism.
Difference between Spherical & Cylindrical Value
Human eyes are spherical in shape whereas astigmatism turns a patient’s eye slightly oblong. This irregularity in the cornea makes it difficult for the lens of an eye to focus light at one point hence distorted/blurred image is formed. Spherical value indicates the amount of correction required for nearsightedness and farsightedness where former is indicated with a minus sign and later is shown via plus sign. On the other hand, CYL is the amount of the correction of the lens power required for Astigmatism. A perfect eye needs no cylindrical & axis values.
Astigmatism is measured by diopters. Most people have between 0.5 to 0.75 diopters of Astigmatism that needs no correction. Patients with 1.5 or more diopters need either glasses or toric contacts to prevent blurred vision. Toric contacts are weighted at the bottom and they have different degree of correction at each meridian.
UNDERSTANDING THE AXIS IN ASTIGMATISM PRESCRIPTION
As mentioned earlier, it is the degree of the angle at which cylinder has to be placed. AXIS ranges from 1 to 180 but most people fall within the range of 90 to 180 degree.
Astigmatism is not as easily detected as myopia and hyperopia. It is diagnosed during a comprehensive eye exam where the eye doctor performs a number of test including how your eyes react and respond to light. Depending on your life style and preference a doctor may be able to recommend you either glasses or toric contacts to help you maintain the crisp vision.
At Lensupermart, we are able to manufacture toric contacts on request. The custom toric contacts will be able to provide you the crystal clear vision without any annoyance that is common with glasses. Either get your toric contacts in color or go for clear toric contacts, we are just a click away.