(1) The process of vision formation is as follows: the light reflected by external objects passes through ① cornea and aqueous humor, enters the eyeball from the pupil, and then forms a clear object image on ⑧ retina through the refraction of ⑧ lens and ⑨ vitreous body. The object image stimulates the photoreceptor cells on retina, and the nerve impulses generated by these photoreceptor cells travel along the optic nerve to the visual center of cerebral cortex, thus forming vision.
(2) When looking at the near objects, we must increase the convexity of the lens through the contraction of the ciliary muscle, so that the near objects can fall on the retina, so that we can see clearly.
If you work at close range for a long time, such as reading, writing, watching TV, playing game machines, etc., your eyes will be nervous for a long time, your head will lean forward, your eyeball will be constantly congested, your intraocular pressure will increase correspondingly, and your extraocular muscles will be nervous and oppress your eyeball, or your blood circulation will be hindered due to the traction of vortex veins during adjustment, which will weaken the resistance of the sclera and lead to excessive convex lens, which cannot be restored to its original state. In severe cases, the anterior and posterior diameter of the eyeball is too long, and the object image formed by the light reflected from distant objects falls in front of the retina, so the distant objects cannot be seen clearly, resulting in myopia, which needs to be corrected by wearing a concave lens.
So the answer is:
(1) Retinal visual center (or a certain area of the brain)
(2) [8] lens fovea