FAQ Prescriptions

We've compiled a list of commonly asked questions about prescriptions. If you are unable to find the answer to your question, please contact us for further assistance.

Most exams last about 20 minutes. However, if you choose to have your pupils dilated at the time of your exam, your appointment could last up to 40 minutes. (Heads up: Dilations can cause your eyes to be sensitive to light for several hours after your exam. Best to book your appointment for a time when you can rest up afterward!)

For all prescription orders, Muunel offers 1.56 mid Index lenses. Mid- Index lenses are thinner and lighter than 1.5 lenses, making them optically superior. This allows us to offer quality prescription lenses to our customers at an affordable price.

In addition to our non-magnified and prescription glasses, we also carry stock reader glasses available in +1.0, +1.5, and +2.0 power; we do not offer bifocals at the moment.

It’s super easy to order Non-Rx glasses from muunel. After clicking on the glasses page button, select “Add to cart” or “Non-Prescription” if you are in the Prescription drop-down window.

Ordering reading glasses through muunel is easy! Once you have selected a frame, click “Select Lenses” and follow the below steps:

1. Indicate that you would need reading glasses by selecting “Reading” from the drop-down.

2. Next, you’ll need to choose the number from the drop-down and click “Add to Cart.”

if you don’t find the power you need, you can also order it through the “prescription” area.

Your pupillary distance (PD) is the measurement of the distance between your pupils. This measurement is used to determine where you look through your glasses’ lens and should be as accurate as possible.
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Here is a list of some optical abbreviations that will help you to understand better the optics world:

ADD (also NV-ADD): the Near Vision (NV) Reading ADDition correction on a multifocal Rx. It can be used for bifocal or progressive glasses or single-vision reading, or computer (intermediate) vision glasses.

Near Vision Reading Addition

AR: Anti-Reflective. A coating that reduces reflection on the lenses.

AXIS: the angle at which the Cylinder (CYL) is placed on a lens to correct astigmatism. It ranges from 1 to 180.

BAL: the Rx calls for balance lenses, meaning the same Rx for each eye. When a person has no sight in one eye, both lenses will have the same thickness.

BD, BI, BO, BU: a prism correction on your Rx (may be indicated with Δ, and one of these four abbreviations. The B stands for a base, and it could be base down (BD), based in (BI), base out (BO), or base up (BU).

CYL: the Cylinder. Combined with the AXIS, the CYL corrects astigmatism.

DS: the abbreviation for diopter simplex. An eye dr. May write DS on an Rx in the Cylinder (CYL) field if no astigmatism correction is needed.

DV: distance vision.

FT: flat-top bifocal.

NV: near vision.

NV-ADD (also ADD): the Near Vision (NV) Reading ADDition correction on a multifocal Rx. It can be used for bifocal or progressive glasses or single-vision reading, or computer (intermediate) vision glasses.

OD: Latin for Oculus Dexter, meaning the right eye.

OS: Latin for Oculus Sinister, meaning the left eye.

OU: Latin for Oculus Uterque, meaning each eye.

PAL: Progressive Addition (or Adjustment) Lens: sometimes, on a Progressive Rx, an eye dr. will write two different numbers for the NV-ADD, perhaps +2.25 +2.50, to increase the reading power in the NV-ADD for Progressive lenses.

PD (Pupillary Distance): PD is the measurement of the distance between your pupils. This is needed for the eyeglasses manufacturer to know where to place the optical center on each lens to see the glasses well.

PL: Plano. Latin for “flat.” If this is in the SPH section of an Rx, it means no nearsighted or farsighted correction is needed.

RX: a prescription.

SPH: the first section on an Rx. It corrects nearsighted or farsighted vision.

UV: the abbreviation of ultraviolet. UV light is invisible to the human eye, but UV light gives us a sunburn, and too much exposure to it can damage the eye—all of the lenses Munnel Optical offers come with 100 percent UV protection, for free.

VA: Visual acuity: how well the eye can see. Sometimes this may be written on an Rx, with a number such as 20/20. This would indicate that with eyeglasses made to this Rx, the vision would be corrected to 20/20 vision.
Want to learn more terms? At the following link, you can deepen your knowledge

If you need glasses, your eye doctor or ophthalmologist will provide you with a prescription for corrective lenses. Eyeglass prescriptions may be written differently, though most are either printed or handwritten in horizontal rows. The first row is the prescription for the right eye (OD), and the second row is for the left eye (OS). These rows are three values: Sphere (SPH), Cylinder (CYL), and Axis.
– SPH number corrects for nearsighted [indicated with a minus (-)] or farsighted [indicated with a plus (+)] vision.
– CYL number and AXIS number correct for astigmatism. You may also have another field labeled as ADD, which corrects the reading power used in a bifocal or progressive lens.
Lastly, eyeglass prescriptions sometimes include the pupillary distance (PD) measurement, which is the distance between your pupils. PD is needed to determine where the lens’s optical center will be for clear, accurate vision. An eyeglass prescription usually expires in one year, depending on which state you received your eye exam.

Bifocal lenses usually have two different viewing zones. The top part of the lens is used for distance vision, and the lower part is used for reading. There is a clear visible line between the view focus of bifocal lenses.

On the other hand, the progressive lenses do not have any line. Progressive lenses offer different viewpoints seamlessly. It means that you don’t need separate view zones in your lens to correct nearsightedness and farsightedness. The lens automatically does the job.

OS and OD are Latin words that stand for Oculus Sinister and Oculus Dexter. These terms are often written on your eye prescription. OD refers to the right eye, and OS refers to the left eye.

In terms of eyewear, the sphere tells you how strong your eye prescription needs to be. Axis is used to represent the measure of astigmatism, and the numbers written under the cylinder represents how much power is needed to correct astigmatism.

The greater the number written on your prescription is, the more strong your prescription will be. If there is a minus symbol with your numbers, it means you are nearsighted. On the other hand, if there is a plus symbol, it means you are farsighted.

The axis and cylinder represent astigmatism on your prescription. It means that the front of your eye has an irregular shape. Due to astigmatism, the light is not reflected on your retina properly, and you have blurry vision. It usually occurs with far or nearsightedness.

A diopter is a unit used to measure the strength of eyeglass lenses. The numbers under the OS and OD columns of your eyeglass prescription is measured in dioptres.