What is the location and shape of the distance line?

The distance line is located on the adaptation circle, which is a trace of a circle or arc that lies on the adaptation circle and surrounds the pupil.

①How many distance line are specified by the evaluation system?

The evaluation system on the distance line is divided into three shapes: one is that there is no trace of the surrounding pupil on the adaptation circle; the other is that there is a regional arc trace on the adaptation circle, and the third is surrounded by traces of the entire pupil.

②How is the difference between the large distance line and the small distance line?

The size of the distance line is mainly determined by the diameter of the surface sand's capillary. When the trace width of the distance line is larger than the capillary diameter, it is called coarse, and when the trace width of the distance line is smaller than the diameter of the capillary, it is called slender or small.