Not usually. Usually this is a function of genetics and the normal aging process.
No. Your eyes can feel tired if you don't get enough sleep. If you bury your face in the pillow and put pressure on one eye it can cause distortion of the vision for a while when you wake up, but no permanent change.
Poor eyesight. People who do not get enough sleep frequently have dry eyes which makes it hard to see. The use of artificial tear drops will help the vision in this situation.
It can. Luis, I assume you are talking about a child? If so, poor nutrition can lead to slower growth, causing a smaller head circumference. Consult your pediatrician, and follow their nutritional guidelines to better assist your child's growth. Hope this helps!
Unlikely the issue. Head size is usually determined by genetic factors from one or both parents. In some, brain abnormalities or syndromes that result in poor development of the brain structures will result in less natural push to create a larger skull. These patients are significantly impaired.