1. Measuring the geometric center distance of spectacle frames: prepare a pair of unprocessed rimless spectacle frames, and measure the geometric center distance of rimless spectacle frames with a pupil distance ruler.

2. Placement of spectacle frames: Place the rimless spectacle frames with plastic linings on the measuring bracket of the focal meter without power supply, and the left and right spectacle frames are in contact with the mirror table.

3. Adjust the position of the baffle to make the measuring hole close to the center of the pad, lift the fixed bracket to fix the pad, and mark three printing points.

4. Lift the fixing bracket, remove the frame, and connect the three printing points into a straight line with an oil pen and a pupil distance ruler, which is the horizontal reference line.

5. Dismantle the frameless frame with a sleeve and place the parts in sequence.

Principle: It is the principle of lens imaging.