1、 Test purpose:

Test the center point of eccentric lenses, mainly for detecting the horizontal and vertical differences in prism power.
2、 Prism degree tester testing method:
1. Turn on the laser button and temporarily do not place the sample on the head model. First, make sure that only one red dot appears at the center of the target. In fact, this red dot is composed of three points stacked together: one is the left eye point, one is the right eye point, and the other is the hole at the center of the base plate hole.
2. Place the model on the headform and adjust the sample according to the measurement instructions
3. Cover the left lens of the sample, observe the position of the red dot on the target, and record the deviation of the horizontal and vertical lines of the red dot on the center of the target, which can be transmitted through the right lens of the sample with laser light.
4. Cover the right lens of the sample, observe the position of the red dot on the target, and record the deviation of the horizontal and vertical lines of the red dot on the center of the target, which can be transmitted through the left lens of the sample with laser light.
5. Record the deviation value closest to 0.5mm, and record whether the deviation value is at base in or base out for each measurement (base in refers to the cross shaped central axis before the laser light is irradiated onto the target, and base out refers to the divergence from the central area to the outer measurement part when the laser is irradiated).
6. Each sample is tested by repeating steps 2 to 5.
7. Turn off the laser power.
8. Calculate the prism degree difference of each plane (horizontal and vertical lines) for each sample.