PD is the distance between the two optical centers of the lens, which is critical to the comfort and visual effect of wearing eyeglasses. A suitable interpupillary distance can ensure that light enters the eyes at the correct position, making vision clear without eye fatigue. If the interpupillary distance is inaccurate, the glasses may put pressure on the bridge of the nose or ears, causing discomfort and pain. In addition, the wrong interpupillary distance can also cause problems such as blurred vision, glare, and distortion, which affect the normal performance of vision.

It should be noted that the interpupillary distance of each person is different, so when purchasing glasses, it should be measured and adjusted according to the individual interpupillary distance. Generally speaking, optical shops will use professional measurement methods to ensure the accuracy of pupil distance. Also, since IPD may change over time, regular IPD measurements are recommended to maintain eyeglass fit. In conclusion, the correct eyeglass IPD is crucial for a good visual experience and comfort.