When a retina catches the light |
from outside as an image, a crystalline |
lens changes to a concave or to a |
convex automatically by the function of |
muscles. You have a myopia |
(nearsightedness) if the lens is hard to |
concave and a hyperopia |
(farsightedness) or presbyopia |
(farsightedness due to old age) if the |
lens is hard to convex. |
If there is something wrong with |
your eyes, you have stiffness in the |
temple and in both sides of the |
posterior neck. |