Optical accommodative compensation system

1. An optical system presenting accommodation compensation with a required global power addition, the system comprising in combination two multifocal lenses, one of them being an aperture lens and the other a field lens, each of them fulfilling a proper accommodation compensation function, in which the aperture lens presents a first individual power addition defined as being the difference between the maximum and minimum focal powers and the field lens presents a second individual power addition defined as being the difference between the focal powers at the reference points for far vision and near vision, the global power addition being the sum of the individual power additions of the two lenses and lying in the range 2.5 diopters to 4 diopters, and the individual addition of each lens is greater than or equal to one-fourth of the global power addition.

2. An optical system according to claim 1 , in which the addition of each lens is greater than or equal to 40% of the overall addition.

3. A system according to claim 1 , in which the field lens belongs to one of the following categories: a lens having progressive addition, a lens having a power discontinuity.

4. A system according to claim 1 , in which the aperture lens belongs to one of the following categories: a concentric lens, a progressive aspherical lens, a diffractive lens.

5. An optical system according to claim 1 , in which both lenses are of the progressive type.

6. An optical system according to claim 1 , in which the eye to be corrected is aphakic, and said aperture lens is an intraocular lens for implanting the eye as a replacement for the natural lens.

7. An optical system according to claim 1 , in which the aperture lens is a corneal contact lens.

8. Visual equipment for a patient having at least one aphakic eye, the equipment comprising an optical system according to claim 6 and made up firstly of a pair of spectacles possessing a lens placed in register with the eye in question and constituting said field lens of the system, and secondly of said intraocular lens.

9. Visual equipment for a patient presenting presbyopia, the equipment comprising in association with each eye, an optical system according to claim 7 and made up firstly of a pair of spectacles with a lens placed in register with each eye and constituting said field lens of the system associated with the eye, and secondly of a pair of contact lenses each placed on a respective one of the eyes and constituting said aperture lenses of the system associated with the eye.