JoGensko PD Ruler, Pupil Ruler Printed 2 Sides for Left-Hand or Right-Hand Plastic Use, Pupillometers for Measuring Pupillary Distance (PD)

JoGensko PD ruler use on both sides, whether you use your left hand or right hand. The high-definition printing scale on white plastic is easy to read. Packaging?1 piece Material: Durable plastic, not easy to scratch Color?White, numbers are easy to read Printing Scale: 2 sides, easy to use with your right-hand or left-hand JoGensko PD ruler is perfect for hospital, eye clinic, optician shop or use at home. When you buy distance glasses online, you will need a PD ruler to help you measure precisely the distance between your pupils to get a better vision. You can measure your PD yourself or with the help of your friend. If to measure with your friend, ask him/her to stand about an arm’s distance apart, put the notch of the PD ruler over your nose, look straight ahead, then find the middle of your pupil, read the numbers closest to the middle of the pupils. If you measure it by yourself, put the notch of the PD ruler over your nose, hold the ruler stationary and perfectly centered, find the middle of your pupil in a mirror (about 8 inches away), read the number closest to the middle of the pupils.