Prescription Glasses: More Than Meets The Eye.

When you are prescribed a medication from a doctor, the little slip of paper you give your pharmacist contains all the information needed to prepare a proper dosage of the right medicine for your particular condition.

But you get much more with that little slip of paper. You also get how—and why—your particular medicine treats your condition. You get use and care instructions to help you understand your prescription. Even a list of possible side effects should the prescription upset your body’s delicate balance.

Your vision is unique. So are your prescription glasses.

A prescription for eyeglasses works in a similar manner, but specifically for your eyes. If your eye care professional determines you need prescription glasses after an eye exam, the process starts with a written prescription. But that slip of paper actually addresses a whole new world of needs you now have to maintain your healthy sight.

This section gives you the distinct details and information you need to actually understand your prescription eyeglasses. Just like with other medications, prescription glasses are developed for you and you alone—a unique “dose” of eye care that will help you see better, and feel better based on your unique vision problem.

There are many conditions that affect healthy sight—and more specialized lens products and choices—than ever before. Understanding what’s available to you based on your condition will explain your prescription glasses in ways you’ve never imagined.

Common prescription lenses abbreviations.

While not all eye doctors use the same abbreviations, here is a list of commonly used terms you’ll often find on a slip for prescription lenses.

• O.D. stands for "Oculus Dexter", which is Latin for "right eye"
• O.S. stands for "Oculus Sinister," which is Latin for "left eye"
• D.V. "Distance vision" relates to far-sightedness — a condition where distant objects are seen clearly, yet objects close up are seen less clearly.
• N.V. "Near vision" relates to near-sightedness — a condition where near objects are seen clearly, yet objects in the distance are seen less clearly.
• SPH stands for "sphere", and corresponds to numbers that indicate the degree to which a patient is near-sighted or far-sighted
• CYL means "cylinder", and corresponds to numbers that indicate the amount of astigmatism present in a patient's eyes. Astigmatism is an eye condition resulting from an irregular curvature in the eye, causing mild, moderate or severe blurred vision.
• AXIS corresponds to numbers indicating the orientation of astigmatism in the eyes — how and where the irregular curvature occurs.
• PRISM is a prescription element that's added if your eyes need help either working more effectively together, or staying in proper alignment.
• PD stands for "Pupillary Distance", and measures the distance between your pupils (in millimeters). This measurement helps ensure your prescription is properly placed in your frames.
• Seg Height is a measurement of where your lenses and frames sit relative to your pupils. It is important when fitting multifocal (bifocal, trifocal or progressive) lenses.