2 piece accomodating iol
The shift of the single-optic accommodating IOL and dual-optic accommodating IOL occurs within the capsular bag.However, Preussner proposed a new concept based on the IOL-capsular bag shift to produce accommodation through a magnetic field.
As a consequence, the capacity of accommodation decreases, which hampers to focus near objects.
In other words, in distance vision, in the absence of contraction of the ciliary body, the zonular tension remains, thereby increasing the tension produced in the capsular bag, and reducing the inter-optic separation.
The lowering of tension on the capsular bag causes a reduction in the tension over the spring haptic of the dual-optic accommodating, allowing them to expand, and separate the convergent lens from the divergent lens, as a consequence of the displacement of the convergent lens in response to the contraction of the ciliary muscle.
Despite the loss of accommodation caused by the weakening of the ciliary muscle, it has been shown through pharmacological stimulation by instillation of pilocarpine and in vivo and in vitro studies using ultrasound biomicroscopy and Magnetic Resonance Imaging (MRI) that the function of the ciliary body persist over the years, even in pseudophakic patients.
The persistence of the function of the ciliary body during presbyopia is expected, because each effort to focus on an object made by the presbyopic patient, even wearing reading glasses for near vision, will cause convergence and pupillary contraction, so it will activate the ciliary body.
With the aim of restoring near vision, different devices that produce multiple focuses have been developed and introduced.