How To Do Pupil Measurements for Reading Glasses

When it comes to reading glasses, one size certainly does not fit all. The key to comfortable and effective reading glasses lies in the precise measurement of your pupils. This might sound like a task for the professionals, but with the proper tools and guidance, you can do it right at home.

How can you accurately measure your pupils for reading glasses? We’ll guide you through the process and get you one step closer to that perfect fit.

What Is Pupil Distance?

Pupil distance (PD) refers to the distance between the centers of your pupils. This measurement helps align the centers of your lenses with the centers of your pupils so your vision will be clear and comfortable. If the lenses of your reading glasses do not align correctly with your pupils, you may experience eye strain, blurred vision, or even headaches.

Near Pupil Distance

Near pupil distance, often referred to as near PD, is the measurement used for reading glasses or any task that requires focus on close-up objects. If you’re in the market for men’s readers, you’ll need this number on hand.

Distant Pupil Distance

Known as distant PD, this measurement is used for activities that require you to focus on objects that are far away, like driving or watching television.

Tools You’ll Need

You probably have all the equipment you need for this task lying around the house. Gather the following tools for your pupillary measurement:

Millimeter Ruler

This ruler will help you take precise measurements. You do need a ruler with a millimeter scale, as pupil distances are usually measured in millimeters.


A bathroom mirror or a vanity mirror works perfectly for this task. The mirror allows you to see your eyes clearly while taking measurements.

Marker or Eyeliner Pencil

You will use this tool to mark points on your face for easier measurement. Make sure the marker or pencil you choose is safe for skin contact and can be removed easily.

The Measuring Process

Position yourself about 8 inches (20 centimeters) from the mirror so you can see your eyes clearly without straining. Use your washable marker or eyeliner pencil to make a small dot on the mirror directly over each pupil. Keep your gaze straight ahead and don’t shift your focus.

Now, hold your millimeter ruler up to the mirror and align it horizontally with the marks you made. The measurement between those marks is your pupil distance. Write it down as soon as possible to avoid forgetting it. Note whether it’s your near or distant measurement, depending on what you were focusing on when you took the measurement.

Pro Tip:

Repeat this process a couple of times to make sure your measurements are accurate. If you end up with different numbers, simply average them.

Mastering the art of measuring your pupil distance empowers you to make informed decisions when choosing reading glasses. By taking this measurement into your own hands, you ensure a custom fit that caters precisely to your vision needs.