The interpupillary or pupillary distance (abbreviated as DP) is the distance that passes between the two pupils of the eyes and is measured in millimeters. It is a measurement that does not change over the course of an adult's lifetime: generally in a large person the average distance is 62 millimeters, but can vary between 54 and 74 millimeters; while for children it ranges between 43 and 53 millimeters.
Can I graduate lenses without indicating the interpupillary distance?
No, you cannot: in order to complete the preparation of your prescription lenses, we need to receive a copy of your prescription and to know the value of your interpupillary distance.
Measuring interpupillary distance at home
Our advice is always to consult specialists, but if you would like to satisfy your curiosity and know your interpupillary distance, you can also do it at home with very few items. All you need is a mirror and a ruler; if you want you can get a family member or friend to help you. Those who have very dark eyes may have more difficulty identifying the pupil, therefore, you need a room with good lighting.
Two different methods can be used to measure interpupillary distance at home:
- The first requires the person to wear eyeglasses well on the nasal septum and alone with the help of a mirror mark with a marker directly on the lens the point representing the center of the pupil. On the other hand, if the cooperation of a person is needed, it is good not to look straight ahead, but at the ear of the person in front of you. For example, if we are taking the measurement of the right eye one should look at the opposite ear of the person who is taking the measurement. The operation should also be repeated for the left eye in the same way. At the end, the two dots made on the lens will be measured with a ruler and this will be the interpupillary distance. At the end of the measurement, we recommend cleaning the glasses well.
- The second, on the other hand, does not involve the use of glasses, but requires the person to stand about 20 cm away from the mirror in a well-lit room. In this case, a ruler is needed to be held horizontally at eyebrow height. With a straight head, close the right eye and align the zero of the ruler with the center of the left pupil. Then open the right eye and see the measurement considering the center of the right pupil. Note the recorded DP measurement, and then repeat the measurement one or more times by reversing the starting eye. If the measurement is taken by another person, be careful to look over the head of the friend or family member.
