Pupil Distance Problem Of Reading Glasses

When wearing reading glasses for the first time, you need to know about the near PD (pupil distance), due to the ensemble effect of the human eye when seeing near, the visual axis rotates inward, making the near pupil distance (33cm reading distance as an example) smaller than the far (head-up) PD 4~6mm. Reading glasses have an important optical index OCD (horizontal distance between optical center points of two lenses), OCD and PD should be as consistent as possible. The national standard stipulates that there is a difference range between the two, sunset red reading glasses according to the national standard relevant provisions of ±3mm tolerance, that is to say, a near PD=62mm guests, to choose the reading glasses OCD value can be between 59-65mm. However, the best solution is to choose glasses with an OCD value less than the pupil distance. Wearing glasses with an OCD value far greater than the pupil distance will cause sore eyes, easy fatigue, and inability to concentrate vision. If the guest pupil distance is too small and too large, so that the mirror can not be selected, the mirror can not be assembled (no large frame, large piece), then the non-focus reading glasses are the best choice.