Accommodating intraocular lenses for patients with cataract a review

Pseudoaccommodation may be accomplished by the induction of certain amounts of higher order aberrations and achromatization, among other less important methods [2], and they should be studied in lenses wherein real accommodation is the target as it is often masqueraded in the outcomes of AIOLs [3].Some of these techniques are based on the adequate performance of the ciliary body using part of the physiological accommodative mechanism, but a surgery for the “real” restoration of accommodation has not yet arrived for clinical practice.Helmholtz (1856) proved that accommodation is accomplished by the change of the power of the crystalline lens associated with the active action of the ciliary body.

This fact made these lenses to be almost abandoned in the last few years, but there are currently other AIOL models being used with innovative mechanisms of action and different anatomical support outside the capsular bag that offer encouraging preliminary results that could bring a new potential of application to these types of lenses.According to Fincham’s findings where the curvature of an excised senile lens is considerably less than that from a juvenile one [12], the loss of accommodative power (presbyopia) is essentially due to the progressive failure of the capsule to mold the lens into a more spherical shape when the zonule is relaxed as a consequence of the progressive sclerosis and hardening of the lens substance with age.Nevertheless, it has been demonstrated that the anterior zonular attachment on the equatorial edge of the lens shifts forward with age [13], and these changes in the configuration of the ciliary muscle may reduce the ability of the zonular fibers to release tension on the lens during accommodation thereby playing a role in the development of presbyopia as well.Almost all surgical techniques that have been proposed to date for the surgical correction of presbyopia are based on the acquirement of pseudoaccommodation [1].Pseudoaccommodation comprises a group of techniques that can improve near vision on the basis of the use of the cornea or intraocular lenses (IOLs), resulting in an increased depth of field, multifocality or both [2].

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