After the age of 40, as the lens of the human eye gradually hardens, we can only adjust the distance between the eye and the object viewed. When we look at the nearby object, we must move far to see it clearly. The state of the eye is called presbyopia.
The old flower degree is related to age. For example, at the age of 45, the presbyopia is 150 degrees. By the age of 50, whether you wear glasses or not, the presbyopia will increase to 200 degrees. At this time, reading books and reading newspapers will inevitably lead to difficulties in reading. If you have a suitable magnifier light on your hand, it will be much more convenient.