In people with myopia, the focal length of the eye is less than the diameter of the eye. To eliminate this disadvantage, pupils with diffusing lenses are used. In people suffering from farsightedness, the focal length of the eye is greater than the diameter of the eye. To eliminate this disadvantage, glasses with collecting lenses are used.
Remember: The process of learning a person lasts a lifetime. The value of the same knowledge for different people may be different, it is determined by their individual characteristics and needs. Therefore, knowledge is always needed at any age and position.