During the day, your PD can vary about 3-4 mm depending on your viewing distance. For instance, if your PD is 61 mm when looking at distant objects (i.e. street signs, chalkboard, TV, etc.), it narrows to 57-58 mm when viewing objects within 16-24 inches from your eyes.2018-10-23
What if PD is off by 2mm?
If the PD measured was 2mm off initially, by using a millimeter rule, the net cumulative error might be 4.5mm or more. However, you were not aware of the original 2mm error. A corneal reflection pupillometer is worth the investment.
What if pupillary distance is off by 1mm?
What if PD Is Off by 1mm? When the PD is wrong by a millimeter the outcome for the wearer will be very different depending on the lens power in the glasses. ... This distance multiplied with the lens power equals the deviation a wrong PD produces.
How do I know if my PD is wrong?
The wrong PD can induce eye strain, fatigue, headaches and blurry vision. If you have a high prescription and the wrong PD these symptoms are often much worse. In my practice, some patients will complain that they “just don't feel right”. Sometimes it is a vague sense that something is wrong with their glasses.2017-12-26
How off can your pupillary distance be?
Measurement ranges Average pupillary distance for an adult is between 54-68mm, with acceptable measurement deviations generally falling in between 48mm and 73mm. The range for children is approximately 41-55mm.