How to Determine Your Pupil Distance for Prescription Lenses

Your pupillary distance (also called PD) is the distance between the center of your pupils. There are actually two measurements of PD because as you look into the distance, your eyes are looking straight ahead, but as you look close to read, your eyes converge an average of three millimeters. The two measurements are called distance PD and near PD and are measured with an optical machine called a pupilometer or an optical ruler.

Things You'll Need

• Ruler with millimeters

Show More

Instructions

• 1

  Obtain a written copy of your prescription from your eye care practitioner. Your optical prescription contains the information needed to make eyeglasses and most eye doctors record your PD on the prescription as two sets of numbers written as distance PD and near PD. The numbers are in millimeters and have distance first, near second, and are separated by a slash, such as 63/60.

• 2

  Measure your PD with a ruler. This is difficult to do yourself, even with a mirror so ask someone to help you. Sit across from them at the same eye level about two feet apart.

• 3

  Look straight ahead into their eyes. Have them hold the ruler in front of your eyes, lining up the line at zero on the very center of your right pupil and have them measure over to the very center of your left pupil as you look straight ahead. Note the number, most distance PD average 60 to 65 millimeters in adults but can be lesser or greater.

• 4

  Recheck the measurement a second time for accuracy, making sure you are looking straight ahead and not moving your eyes as your helper measures.

• 5

  Measure your near PD by having the person using the ruler place their other hand over their nose with their index finger pointing up. Look at their finger and have them remeasure your PD as in Step 3. The difference should be approximately 3 millimeters less than your distance PD.