Human is capable of seeing clearly to different distances thanks to the changing of the shape of crystalline lens. During years eye's capability of changing the shape of the lens decreases. Therefore middle-aged people, who once saw well close and far, will have the need for so-called reading glasses. This state is called the presbyopia. People with far-sightedness will have the need for spectacles earlier, people with near-sightedness later or never.

The options for getting rid of reading spectacles are multifocal artificial lens implantation or