Pupil distance instrument is a measuring instrument used to measure the distance between the two pupils of the human eye in the process of optometry.
The measurement principle of pupil distance instrument is that the visual beacon illuminated by the light source is imaged by the optical system at a specific working distance in front of the patient's eyes, and when the patient looks at the visual beacon, the visual axis of the left and right eyes intersect at this specific working distance. At this time, the light on the patient's left and right corneal surface to form a mirrorspot. Through the eyepiece, the optometrist can see the reading gossamer and these two reflecting points at the same time. After moving the left and right reading gossamer to align with the reflecting points of the left and right eyes of the patient, the pupil distance of the patient can be obtained on the display screen.
The verification device of pupil distance instrument is composed of an adjustable table with a two-dimensional motion direction and three standard sleeves with nominal pupil distance values of 55mm, 65mm and 75mm, among which the deviation between the actual center distance value and the theoretical center distance value of the three standard sleeves should be controlled within 0.1mm.
The pupillometer calibration device is equipped with two OD standard analog eyes to simulate the reflection spot of the target image observed from the pupil of the patient under working conditions.