OD stands for “oculus dexter,” or right eye. The term “plano” (pl) means there is no refractive error. A minus sign indicates the need for a concave lens to correct nearsightedness.
#Od and os which is right and left plus
Most doctors use a plus sign to indicate the need for a convex lens to correct farsightedness. Such a prescription is called spherocylindrical. The angle number is the third number in a prescription for people with astigmatism. A line from end to end, going though the center of the football, is called the “axis.” It’s angle is based on the direction of the axis and identified in degrees, as on a protractor, with 0 degrees to the right and 180 degrees to the left. The “football” can be vertical, horizontal, or at an angle. That condition in the eye is called “astigmatism.” A lens correcting an eye with astigmatism, therefore, would have two diopter numbers. This is because the curve around the center of the football is different than the curve from one tipÊto the other. If your cornea is shaped more like the oval surface of a football, two focal points exist. The number is the “refractive error,” or the number of degrees you are away from normal vision. It looks like dollars and cents, but the units are called “diopters” (D). The focus power of the prescription would be a single number such as 2.25. No matter how you slice it, vertically, horizontally or at an angle, the curve is always the same. The cornea is normally spherical, like a basketball. This means a simple spherical lens (like a magnifier or minifier) is used, and there is only one focal point. If you are only nearsighted (myopic) or farsighted (hyperopic), then you have what is called a “spherical” prescription. The doctor’s prescription is due mainly to the shape of your cornea. It is also available as part of an audiovisual presentation, “All About Eyeglasses”.Ī spectacle lens tries to focus a clear image onto the retina.
This information will help you decipher those numbers and abbreviations on your spectacle prescription.
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