When it comes to eye prescriptions, there is a lot to understand. Some of the terms you will hear at your optometrist will be ambiguous, and you might not understand what they mean. There are several medical terms used by doctors when referring to different parts of your eyes and eye conditions. Some of these terms include; myopic, axil, prism, sph and cyl, among others. CYL is a term used by doctors specialising in eyes to refer to the cylinder. Different individuals have different optimal capabilities; this includes lens power. The cylinder is a term used to refer to the amount of lens power a person needs for astigmatism. Astigmatism is a condition that refers to the imperfection of the eye curvature leading to blurred vision and nearsightedness.
Common abbreviations in eye prescriptions.
CYL
CYL are abbreviations for the cylinder. It refers to the required lens power to fix astigmatism. The readings are recorded in a column with negative, zero and positive values. If the recorded reading is zero, the patient doesn’t have astigmatism; a negative reading means that the correction is for nearsightedness, while a positive one is for far-sightedness.
AXIS
Axis is a term used to refer to the lens meridian, which does not have the cylindrical power required to fix astigmatism. The axis is labelled from 0-180. The meridian reading always follows the cylindrical power in any prescription. The axis defines the angle between the meridians; in most cases, it is always 90 degrees.
ADD
In eye prescriptions, ADD refers to the magnifying power used in bifocal, progressive and multifocal lenses. The Add value is always positive even when it’s not indicated, and it is always equal for both eyes. The added value always ranges between +0.75 and 3.00
PRISM
Some individuals suffer from alignment problems. In such a situation, prisms are used to correct the situation through prisms diopters. Prism lenses do not have corrective powers and thus can’t be used to correct refractive errors. These lenses trick the eyes into believing that an object is placed in a different location, which fixes alignment problems. There are some terms used in this case, such as;
BU –Base up
BI – Based in
BO – Base out
BD – Base down
Frequently asked questions about eye prescriptions.
When ordering eyeglasses online, there are several things that you ought to consider, such as eye prescriptions and eyeglass style. There are some common questions asked about eye prescriptions, such as;
In eye prescriptions, what does CYL mean?
CYL are abbreviations for the cylinder, which is the lens power required to fix astigmatism. Its readings are negative, positive and zero; if it’s negative, then a lens to fix short-sightedness; if positive, then a lens is needed to fix long-sightedness. When at zero, then the patient does not have astigmatism.
Can the human axis change?
Yes, the human eye axis changes with changes in the human eye cornea. When the eye axis changes by more than 90 degrees, it’s time to seek medical help.
What is a bad human eye axis?
When the eye acuity is at 20/200, it is said to be a bad eye axis, and the patient is considered blind. However, if eyeglasses help improve the condition, the patient can’t be legally blind.
What does a negative reading SPH mean?
In SPH, a negative reading means the patient suffers from short-sightedness; objects appear blurred.
What does a positive reading in SPH mean?
In SPH, a positive reading indicates long-sightedness as near objects are blurred.
