If you are one of the estimated 11 million Americans that has a common vision problem such as nearsightedness, farsightedness or astigmatism, then you probably have a prescription for corrective eyewear such as glasses or contact lenses. Do you understand what your script is for and what it means about your vision?
The common eye disorders mentioned above are known as refractive errors and they occur when the eye doesn’t correctly bend, or refract, light as it enters the eye. Let’s take a look at each of these and what it means about your prescription.
The first step to understanding your eyeglass prescription is knowing what “OD” and OS” mean. They are abbreviations for oculus dexter and oculus sinister, which are Latin terms for right eye and left eye. Your eyeglass prescription also may have a column labeled “OU.” This is the abbreviation for the Latin term oculus uterque, which means “both eyes.”
- Nearsightedness or myopia is when light enters the cornea and is refracted, or “sent” to a spot in the eye before reaching the retina. For people who are nearsighted, the light waves are sent to the wrong place on the retina. Nearsighted is a condition where objects up close appear clearly, while objects far away appear blurry. The extent or amount that a patient is will be denoted in the number on the prescription. If the number appearing under the heading sphere has a minus sign (–), you are nearsighted.
- Farsightedness or hyperopia means that the light is refracted to a place beyond the retina. Farsightedness means that items far away are clear, but activities like reading and knitting are difficult, because nearby objects appear fuzzy or unfocused. Some people may not notice any problems with their vision, especially when they are young. If the number appearing under the heading sphere on your prescription has a plus sign, you are farsighted.
- Astigmatism is another refractive error, distorting objects both near and far, so that everything appears out of focus and skewed.
Call Independent Eye Care to have your annual exam and find out more about your prescription.