True, Mechanical digestion begins in the mouth as the food is chewed. Chemical digestion begins in the mouth when food mixes with saliva. Saliva contains an enzyme (amylase) that begins the breakdown of carbohydrates.
When you chew, you are undergoing mechanical digestion. By the time the food reaches your stomach, it will undergo chemical digestion. Hope this helped :)
Not enough information is given but my mom is in the medical feild and she says that a condition common with age is presbyopia. It causes the leanses in your eye to become less flexable and less able to thicken therefore less able to focus on near by objects. Another is catteracts which I assume you already know about so I will not explain.
