Many contact lens wearers are often aware of the fact that they need a prescription for getting a pair of lenses. But the thing here is how many of them are aware of the terms in the prescription. Even though it is not required by you to know about the terms, but a little knowledge on the terms will let you know more about your eye than the doctor. If you know what exactly the doctor is prescribing, and kind of problem you are having it makes you feel responsible about what you are doing. So let us see few terms and their full forms to let you be aware about your problem.
- OS and OD: OS is oculus sinister, and OD is oculus dexter. These two columns are used to represent the left and right eye respectively.
- Power: This is a word which is seen quite often in the sight related prescriptions. This is nothing but the refractive power of the lens which is measured in diopters. This measurement is required to mention the amount of vision correction required by the eyes. The power can be negative(minus) or positive(plus). The minus power indicates near sightedness and plus sign indicates far sightedness.
- Base Curve and Diameter: The lens of the eye is measured in order to get the contact lens of the same size. The term base curve represents the back side curve of the lens which is measured in millimeters. The diameter of the lens is denoted by the term diameter which is also measured in mm.
- Brand: It is necessary in the US that the prescription should mention the brand of the contact lenses. And the patients are supposed to take the brand as mentioned in the prescription.
- Color: This is the term which is usually seen in colored or fancy lens prescription which describes the color of the lens prescribed.
- Cylinder and Axis: These terms can be seen in the case of special cases, say with astigmatism. Cylinder represents the magnitude of astigmatism and axis represents the orientation of the cylinder and is measured in degrees.
These are terms to be aware of in order to make the prescription clear to you.