1）How to Judge it thin or thick?

The diameter of the capillaries is compared with the diameter of the blood vessels of the surface sand. When the diameter of the capillaries is large or equal to the diameter of the sand vessels, we call it thick. When the diameter of the capillaries is smaller than that of the sand vessels, we call it thin.

2）How to Judge it sparse or concentrated?

Divide the pigeon's eye into 12 time zones. Here we take a time zone as an example: when the number of intersections between the capillaries and the black outer ring in this area is more than the number of intersections between the sand blood vessels and the black outer ring, we call it concentrated. When the number of intersections between the capillaries and the black outer ring in this area is less than the number of intersections between the sand blood vessels and the black outer ring, we call it sparse.

3) What is the function and significance of capillaries?

Through the flow of blood, carrying and providing means of material exchange. It is a prerequisite for providing the materials needed for the proper functioning of the internal structure of the eye. It is a way to reflect the health of the eye and the strength of the eye function.