Unlocking the Optical Morse Code

Unlocking the Optical Morse Code

Purchasing a pair of eyewear online is increasingly becoming the new trend. Online eyeglass stores, such as NURILENS, offer a number of vision options from standard single vision lenses to premium progressive lenses. The experience, however, can switch from convenient to stressful when it comes to answering questions about your prescription. Your prescription specifies a unique set of mathematical requirements that enable you to vividly capture the beauty of everything around you. Understanding your vision you have and what the different values on your prescription mean can surely be confusing. 

Here are some of the things you want to look out for when reading your prescription.


Sphere, Cylinder, & Axis

These values represent various precise measurements that help you obtain your optimal vision. They measure the required lens power that are attributed to correct nearsightedness, farsightedness, and astigmatisms. 

  • The Sphere is prescribed either to correct your nearsightedness or farsightedness. Negative values indicate that you are nearsighted, meaning that distant objects appear blurry to you. Conversely, positive values indicate that you are farsighted, meaning that you can’t see nearby objects clearly. 
  • The Cylinder is used to correct your vision if you have an astigmatism. If the cylinder column is empty on your prescription, it either means that you don’t have an astigmatism, or that it’s negligible. 
  • The Axis is a value between 1-180 that refers to the degree value that will help in correcting your astigmatism. If your prescription includes a cylinder value, it will also include an axis. 

Left Versus Right Eye

OD and OS are extremely popular terms in the optical world. They are Latin abbreviations that refer to your right and left eye. OD is the abbreviation for ‘oculus dexter’ which translates to ‘right eye’. OS is the abbreviation for ‘oculus sinister’ which translates to “left eye”.

Which is my prescription type?

While choosing between single vision lenses vs. progressive lenses, remember:

  • Single vision glasses – These glasses are set with the same prescription throughout the lens. As the name indicates, they can be used to correct only one field of vision – either nearsightedness or farsightedness. 
  • Progressive vision glasses – The prescription for this type of glasses contains the standard sphere, cylinder, and axis values, along with an add. These glasses have correction for your distance vision in the upper portion of the lens, and nearby vision correction in the lower portion. A seamless blend allows for you to easily switch from looking at faraway objects, to reading something up close.

As time passes, your vision is likely to change, so it is good to keep in touch with your optometrist every year or two, so that you always have an up-to-date prescription. 

Why do I have an Add on my prescription?

An add value refers to the added magnifying strength needed to help someone see something up close. These values allow you to get progressive or multifocal lenses that have corrections to fix your distant vision (upper portion of the lens), along with adjustments to see things up close (bottom portion of lens).

Pupillary Distance

If your optician or optometrist has ever held up a ruler of some sort to your eyes, they are probably measuring your pupillary distance. Abbreviated to PD, your pupillary distance is a measurement of the distance between the centers of your pupils. 

Your PD might come in one value or two. If your PD is divided between your right and left eye, then each value is a measurement from the center of your pupil to the center of the bridge of your nose.

Your PD is an important value as it allows your glasses to be properly measured for the center of your vision. While there are tools online to help you measure your PD on your own, it’s always best to have an optical professional measure it for accuracy. As compared to the other values on your prescription, your PD is least likely to change from year-to-year. Nevertheless, it’s always good to verify it to ensure an accurate prescription.

Placing your prescription order with NURILENS

We accept orders for different prescription types to fulfill your optical needs! Whether you require a little help reading the small print in a newly published JUNURI book or you are having a hard time seeing the approaching traffic signs, we’ve got you covered! 

Shop our collection of blue-light filtering eyewear to select your favorite pair of frames and get them filled with your prescription today! 

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