Eye exams involve medical abbreviations that can be confusing. Understanding terms like “OS,” “OD,” and “OU” helps you comprehend your eye health and prescriptions. This article clarifies their meanings, providing a clearer picture of your eye exam results and corrective lens prescriptions.
Deciphering OS and OD
In the field of eye care, “OS” and “OD” are standard abbreviations derived from Latin terms. “OD” stands for oculus dexter, which translates directly to “right eye.” Conversely, “OS” stands for oculus sinister, meaning “left eye.” These terms are universally adopted by ophthalmologists and optometrists to precisely identify which eye is being referred to in medical records and prescriptions. While some modern practices might use “RE” for right eye and “LE” for left eye, OD and OS remain the prevalent abbreviations in most prescriptions.
Understanding OU
Beyond the individual eye designations, “OU” is another abbreviation encountered in eye care. “OU” stands for oculus uterque, which means “both eyes.” This term is used when a diagnosis, instruction, or prescription applies equally to both the right and left eyes. For instance, if a specific eye drop dosage is the same for both eyes, “OU” might be used to simplify the instruction. If both eyes have identical lens powers, an eye care professional might use OU to denote this.
How These Terms Appear on Your Prescription
An eye prescription typically presents information in a grid or chart format, with distinct sections for each eye. The “OD” column or row lists the specific corrective values for your right eye, while the “OS” column or row contains the values for your left eye. This layout ensures that lenses are precisely tailored to the unique needs of each eye, as it is common for prescriptions to differ between the right and left eyes.
Within these columns, you will find abbreviations like “SPH” (Sphere) for nearsightedness or farsightedness correction, “CYL” (Cylinder) for astigmatism, and “Axis” indicating the orientation of astigmatism. A minus sign (-) before a number indicates nearsightedness, while a plus sign (+) or no sign signifies farsightedness. The “OU” designation, if present, appears when the prescription for both eyes is identical, indicating that the same correction applies to both.