Contact lens which is right and left number 3 and 4

#Contact lens which is right and left number 3 and 4 plus

They are abbreviations for oculus dexterВ and oculus sinister, which are Latin terms for right eye and left eye.

The first thing to understand your eyeglass prescription is knowing what 'OD' and OS' means. This article will help you decipher all parts of your prescription and discuss it knowledgeably with an optician or when you buy eyeglasses online.

Roy Cole, O.D., F.A.A.O.You've just had an eye exam and your optometrist or ophthalmologist has given you an eyeglass prescription, but what do all those numbers on your eyeglass prescription mean?ДЄnd what about all those abbreviated terms, such as OD, OS, SPH and CYL? More information about glasses and visual acuity:Д¬omputer Vision Syndrome and Computer Glasses That is your вЂњacuity.вЂќ Someone with this prescription could measure better than 20/20 acuity, while someone else with the same prescription could measure 20/200. Meaning your left eye (OS) is slightly farsighted, needing a focus power of +1.25, and no astigmatism is present.ДЇinally, remember that the prescription has nothing to do with how well you see. the angle of the axis is tilted slightly to the right (at 85 degrees on the protractor) has 2.50 units (diopters) of astigmatismДЈ. slightly farsighted, needing a focus power of +1.25Дў. So a spectacle prescription for one of your eyes can look like this:ДЎ. OS stands for вЂњoculus sinister,вЂќ or left eye.ДS stands for вЂњdiopter sphere.вЂќ If this appears in the 2nd and 3rd columns of your prescription, or if the columns are blank, you have no astigmatism. OD stands for вЂњoculus dexter,вЂќ or right eye.

The term вЂњplanoвЂќ (pl) means there is no refractive error. A minus sign indicates the need for a concave lens to correct nearsightedness.

#Contact lens which is right and left number 3 and 4 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 вЂњaxis.вЂќ ItвЂ™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 вЂњfootballвЂќ can be vertical, horizontal, or at an angle. That condition in the eye is called вЂњastigmatism.вЂќ 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 tipГЉto the other. If your cornea is shaped more like the oval surface of a football, two focal points exist. The number is the вЂњrefractive error,вЂќ or the number of degrees you are away from normal vision. It looks like dollars and cents, but the units are called вЂњdioptersвЂќ (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 вЂњsphericalвЂќ prescription. The doctorвЂ™s prescription is due mainly to the shape of your cornea. It is also available as part of an audiovisual presentation, вЂњAll About EyeglassesвЂќ.ДЄ 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.