What is the position and function of the adaptation circle?

The adaptation circle is located between the pupil and the iris, and its function is to assist and coordinate pupil contraction and expansion. As a sphincter, we can find many traces after a long period of motion to determine certain specific motion characteristics.

①How to determine the width of the adaptation circle?

Under normal circumstances,We call it wide when the width of the adaptation circle is large or equal to 1/8 of the outer radius of the outer ring. We call it the middle when the width of the adaptation circle is between 1/15 and 1/8 of the outer radius of the outer ring. We call it narrow when the width of the adaptation circle is less than 1/15 of the outer radius of the outer ring.

②How to judge whether the adaptation circle is flexible?

Judging the elasticity of the adaptation circle, we usually decide in two cases: under the strong sunlight, the adaptation circle is pulled with the contraction of the pupil, and it can be seen that there are obvious radiation traces around the adaptation circle. In the case of insufficient light, the adaptation circle expands with the expansion of the pupil and the width of the adaptation circle is significantly reduced to a thin line due to the expansion of the pupil. The evaluation system calls these two distinct functions "elastic."

③How to judge whether the elasticity of the adaptation circle is strong or weak?

The strength or weakness of the adaptation circle is judged according to the frequency and amplitude of the pupil contraction and expansion. Whether it is under strong light or dim light, the adaptation circle contraction and expansion must have both amplitude and frequency. It is strong. Otherwise it is weak.