Surgical correction of presbyopia is possible via the implantation of multifocal intraocular lenses after removal of the crystalline lens. The cost of these implants is approximately 6 times higher than the conventional monofocal implants routinely used in all crystalline surgery for correction of the resulting ametropia. Spectacles for correcting presbyopia, which are necessary after the insertion of monofocal implants, may also have a significant cost.

The proposed trial will involve two randomized groups of patients in need of crystalline/cataract surgery, with monofocal or multifocal lens implants (the same type of lens in both eyes) leaving them emmetropic for distant vision.

The objective is to corroborate with blind-evaluation the effectiveness of multifocal lens implants in obviating the need for glasses to correct presbyopia, to evaluate the benefits of this type of implant, both in global economic terms (adding the cost of the implants to that of corrective glasses where necessary) and in terms of the improved quality of life of the patients, and to confirm the absence of adverse effects.

Findings will be subjected to a statistical quantification.

Inclusion Criteria:

• Patients of both sexes aged 50 and over, with fully-established presbyopia, requiring phacoemulsification + IOL as the surgical technique for the removal of their cataracts.
• Their capsular bags should be stable, with keratometric astigmatism equal to or lower than 1 diopter.
• Biometric calculations should indicate an IOL for emmetropy within the common dioptric range for both lenses, i.e. between +6 y +34.

Exclusion Criteria:

• Previous corneal refractive surgery
• Maculopathy, amblyopia or other eye conditions that limit visual power
• Occupations requiring special driving licenses
• Keratometric astigmatism higher than 1 diopter
• Any intraoperative posterior capsular rupture or extracapsular reconversion.