【Powe off and Memory Function】The digital PD ruler will turn off automatically when it is set level and turn on automatically when using it to save energy. With the memory function, you do not need to worry losing data.
【Operation】It is suggested to have assistance when performing the test. Place the PD Meter near your eyes, precisely over your nose. Locate the midpoint of your pupils and align it with the white line. The number shown on the LCD screen indicates your pupil distance (Unit:mm). Ensure your eyes are facing forward or towards the tester's nose while measuring.
【Operation】It is recommended to have a second person help you while testing. Put the PD Meter over your nose, as close to your eyes as possible. Then find the center of your pupils, the white line should be aligned with the center. The number displayed on the LCD screen is your pupil distance(Unit:mm). Please keep your eyes looking straight ahead or at the nose of your tester during the measurement.
【Warm Tips】The digital PD ruler is used to measure the distance between two pupils. This is a simple PD ruler, it can help you when you want to purchase eyeglasses online or in eyeglasses store. If you require very high accuracy, this one is not recommended.
【Without Battery】Due to long diatance transportation, the battery is taken out. (23A,12V battery)
【Precise】It is more precise than Vernier PD Ruler. The two white lines is very clear against the dark pupil and the pupil distance is displayed in the LCD screen. What's more, it can measure monocular distance separately. When two pupils centre are aligned with the white lines, press the left (right) black button, it shows the distance between left (right) eye pupil and bridge of nose.