Eye prescriptions often contain unfamiliar abbreviations that can be confusing. This article clarifies the meaning of common terms like “OD,” “OS,” and “OU,” helping you better understand your vision correction needs.
Understanding OD, OS, and OU
On an eye prescription, “OD” is a standard abbreviation from the Latin “Oculus Dexter,” meaning “right eye.” This term consistently refers to your right eye.
Conversely, “OS” originates from the Latin “Oculus Sinister,” signifying the “left eye.” These Latin terms provide a precise and unambiguous method for documenting eye measurements.
“OU” stands for “Oculus Uterque,” meaning “both eyes.” This term is used when a measurement or correction applies equally to both eyes. The consistent use of these Latin-based abbreviations helps maintain clarity in medical documentation.
Deciphering Your Eye Prescription
Beyond OD, OS, and OU, an eye prescription contains other important abbreviations that detail the specific corrections needed for your vision.
“SPH” (Sphere) indicates the main lens power required to correct nearsightedness (myopia) or farsightedness (hyperopia). A negative sign denotes myopia, while a positive sign or no sign indicates hyperopia.
The “CYL” (Cylinder) and “AXIS” measurements are presented together, addressing astigmatism, a condition where the eye’s cornea or lens has an irregular curvature. The cylinder value specifies the lens power needed to correct astigmatism, while the axis indicates the orientation or angle of this correction, measured in degrees from 1 to 180. These values work in conjunction to properly focus light onto the retina.
“ADD” (Add Power) is typically found in prescriptions for bifocal, trifocal, or progressive lenses. This value represents additional magnifying power for reading and close-up tasks, often necessary as individuals age and experience presbyopia.
“PRISM” indicates a special correction used to address eye alignment issues, helping to redirect light so that images from both eyes align properly.
When to Consult an Eye Care Professional
While understanding eye prescription abbreviations is informative, this knowledge is not a substitute for professional medical advice. An optometrist or ophthalmologist possesses the expertise to accurately interpret your prescription and assess your overall eye health. They can explain each component in detail and how it relates to your specific visual needs.
It is always advisable to consult your eye care professional if you have any questions regarding your prescription, experience changes in your vision, or notice any new symptoms. Regular eye examinations are crucial for maintaining optimal eye health and detecting potential issues early. Your eye doctor can provide comprehensive guidance and ensure you receive the most appropriate vision correction.