Eyeglasses | Optical Center SmartBuyGlasses USA

How to Find Out Your Prescription

If you’re wondering how to read your prescription, we’re here to help. Maybe you’re entirely new to wearing prescription glasses, or you’ve just received an up-to-date prescription and want to understand what it means. Understanding your glasses prescription is helpful if you want to know the severity of your visual impairment or want to shop online for your prescription glasses. So let’s get started.

How to get your prescription

Following your eye appointment, you are provided with a copy of your prescription, in the form of a document or a card. If your optician did not provide this, you can call and request your prescription. Professionals recommend you get your eyes checked every two years. If you are concerned your eyes have deteriorated, book an eye appointment.

At first glance, your prescription card might mean nothing to you. However, we’re here to help! Read on to discover the ins and outs of your vision.

How to read your eye prescription

Now that you have your prescription in hand, it's time to understand the glasses prescription. The first terms you should read are OD and OS. OD (oculus dextrus) indicates your right eye and OS (oculus sinister) your left. This way, you can determine which of your eyes may have a stronger prescription than the other.

Farsightedness vs. nearsightedness

Being farsighted is also known as hyperopia, which occurs when you can see objects up-close but struggle to see things far away. On the other hand, nearsightedness, also known as myopia, is when you struggle to see objects close-up. If you are farsighted, the strength of the lenses will be marked with a plus sign beneath 'sphere.' The higher the number, the stronger your prescription. For instance, a lens prescription of +5.50 is stronger than +2.00. If you are nearsighted, your sphere eye prescription will be marked with a minus sign. The more difficulty you have seeing objects up close, the higher your measurement will be.

Pupillary distance on prescription

Knowing your pupillary distance (PD) is essential when ordering prescription glasses online. The PD is the distance between the centre of one pupil to the centre of the other pupil, measured in millimetres. When you buy glasses online, you should enter your PD to ensure your prescription sits exactly where your eyes need it. The pupillary distance on your prescription is often located at the bottom of the prescription card.  

Suppose there is no pupillary distance on your prescription. In that case, you can use our pupillary distance tool to measure it in minutes.

Cylinder on eye prescription

Astigmatism is when an irregular curve in your eye's lens or cornea can blur near and far objects. This common visual issue is indicated on your prescription card with the cylinder label (see image above). The cylinder number indicates the amount of lens power for astigmatism. If yours is blank, you have no astigmatism.

Axis on eye prescription

If your prescription includes cylinder power, it must also have an axis on your eye prescription. The axis indicates the angle between an astigmatic eye's two sections, ranging from 1 to 180. If you have an axis on your prescription card, you have astigmatism.

What is ADD on eye prescription?

Usually located on the far right side of your eye prescription, ADD stands for Addition. This indicates the additional correction you may require for reading, which is used in bifocal glasses, reading glasses or varifocal glasses. ADD on your prescription represents the extra power over the distance prescription.


Now that you understand your prescription, it’s time to shop for a new pair of glasses. With SmartBuyGlasses you can browse thousands of designer brands at affordable prices and even use our Virtual Try-On tool to try your frames digitally before buying. Once you have selected your favourite pair, you can attach a photograph of your prescription or enter the details manually. Shopping for glasses online has never been easier.

We recommend contacting your optician to get an up-to-date prescription and inquire about your eye health. Once you have all of the information you need, it’s time to start shopping for your perfect pair of prescription glasses with SmartBuyGlasses!