The snake has a pair of bright eyes. The snake’s eyes have no blink membrane. The upper and lower eyelids are healed into a transparent film covering the eyes. The eyes can’t move. The eyeball is round. The pupils are round and split. The pupils of poisonous snakes and other nocturnal snakes are mostly split; Daytime snakes generally have round pupils.
Snakes are short-sighted and have underdeveloped vision. They can only see near and far. Nocturnal snakes have a pigment substance called crystalline bird Bixi in the cells of the retina and the posterior wall of the eye, which makes the snake produce visual excitement in the weak light at night. Therefore, it can move freely and capture food without reaching out. When a snake molts, the corneal substance on the surface of the outer transparent membrane also molts at the same time. Therefore, before molting, the transparent membrane becomes turbid and can’t see clearly.