Presbyopia is the loss of accommodation-of being able to focus-of the crystalline lens. The eye focuses the images with the help of two lenses: the cornea and the crystalline lens. The cornea is a fixed lens that can not vary its shape or size. The crystalline lens is instead a lens that is attached to a muscle that allows to vary its shape and, therefore, its power. Thanks to these movements we can focus close and far images. After 45 years, the crystalline lens hardens and loses elasticity. The consequence is that the muscle in charge of varying its shape (ciliary muscle) is unable to do so and the ability to focus -or to accommodate- is lost.
The more far the images are, the more relaxed is the ciliary muscle, but as we approach an object the muscle tenses up to focus. This is why when the muscle loses this ability to accommodate we can not focus correctly on the closest texts or objects.
The most common way to correct presbyopia so far was through the use of bifocal or progressive glasses that allow focusing at different distances. The problem of the glasses, apart from being uncomfortable or producing sweating and irritation in the contact area, is that as the presbyopia progresses, and the crystalline lens is losing its ability to focus, it will be necessary to buy new glasses periodically with the correct graduation.
The permanent, effective and safe alternative is the surgical treatment based on the substitution of the natural lens for an artificial lens, called intraocular lens, with the ability to focus at different distances (multifocality). The technique is called Prelex, is performed under topical anesthesia, is ambulatory (does not require hospitalization) and lasts no more than 10 minutes per eye. At the end of the procedure, the patient can go home on his or her own foot and can begin to make a normal life from the very next day