Interpupillary distance (PD) refers to the distance between the centers of the pupils of a person's eyes.

Interpupillary distance is very important for the correct wearing and use of glasses. Because the distance between spectacle lenses must match the distance from the center of the pupil of the human eye, in order for the eyes to obtain the best visual effect. If the interpupillary distance does not match the distance between the spectacle lenses, it will cause aberrations, line of sight deviation and other problems, causing discomfort during use.

Tools needed: A mirror that fits the wall and a ruler

This scale is your pupillary distance (PD).

Please note: You can repeat the measurement several times to improve accuracy. In most cases, the interpupillary distance of Asian adults is between 50mm and 75mm.