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Glen Abbey Golf Course, Oakville, Ontario

It’s all Greek and Latin to you, abbreviations such as OS, OD and OU, stare at your face as you look at the prescription for your eyeglasses. Although you may not be required to understand everything in it, it helps to get a hang of what it means. An eyeglass prescription is mostly about refractive error correction. A refractive error causes a blur in your vision, and wearing eyeglasses correct that error, depending on what kind of error you have.

The first step to understand the prescription is deciphering OD or OS. OD stands for oculus dexter, while the S in OS stands for sinister, which in Latin mean left and right eye respectively. OU is oculus uterque, which means both the eyes.

Diopter measurement

The unit of measurement in an eyeglass prescription is called a diopter which can either be a negative or a positive number. The negative number is indicative of nearsightedness and a positive number shows farsightedness. A lens for minimizing things is used for nearsightedness while a lens for maximising things is used for farsightedness.

A diopter (D) indicates the power of a lens for it to focus the light on the retina. A nearsighted individual who needs a – 1.00 diopter lens can view objects that are at a one-metre distance clearly, but everything that is father will be blurred, For a farsighted persons who needs a + 1.00 diopter lens, anything closer than one metre is blurred.

The other terms in the prescription are DV and NV, which stand for distance vision and near vision, respectively. NV is indicated if you have glasses purely for reading. If you have bifocals, NV is indicative of the lower part of the bifocal lens.


Spherical (SPH) is the term used to indicate a measurement (in diopters) of your nearsightedness or farsightedness. Cylindrical (CYL) is a term used to indicate astigmatism. Astigmatism is a condition where nearsightedness or farsightedness is not the same in all the directions. The axis is the term used to tell you where the astigmatism is located in the horizontal axis in the eye. It could be a number anywhere between 0 and 180 degrees.

If there is a column that is called ‘Add’ in the prescription, it indicates bifocals. Add is the additional diopter strength added to your prescription with respect to the lower part of your lens. Prism is the quantum of prism power, measured as p.d or prism diopters, which is prescribed for eye alignment issues. Very few prescriptions have this column in them.

Drop by our Oakville, Ontario location to have your prescription checked so you can better enjoy your next golf game at Glen Abbey golf course.



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