Dual optic accommodating lens
Obviously, this ideal AIOL would have a huge impact in refractive surgery and private practice, which explains the interest from the different companies in developing such lenses.This ambition has led to many mistakes in the past (commercial bias, poor methodology to study near vision, non-independent monitorization, etc.), where different types of AIOLs were presented to the scientific community as highly effective to be then discredited later on by independent studies from different authors.
The change in the refractive power of the eye, when the image of a near object is brought into focus on the retina, is defined as accommodation; such a process must involve an increase in the dioptric power of the system [ It is the difference in refractive power of the eye in the two states of complete relaxation and maximal accommodation.The cookies contain no personally identifiable information and have no effect once you leave the Medscape site.Presbyopia still remains the last frontier of refractive surgery.Its surgical management is under constant evolution due to the limitations that exist today with respect to its management, which is probably in relation with the multifactorial basis in which presbyopia is clinically developed in the human.Until currently, virtually all surgical techniques that have been proposed for its correction are based on the induction of pseudoaccommodation in the presbyopic eye, including multifocality.Nevertheless, pseudoaccommodation is not a real restoration of accommodation [The theory of accommodation is largely based on Helmholz's ideas: the capsule has sufficient elasticity to mold the lens into a more strongly curved system than what is necessary for distance vision.
The elasticity of the capsule is held in check by the normal tension in the zonule so that accommodation consists in the relaxation of the tension in the zonule by the contraction of the ciliary muscle.
However, there is not a real change in the IOL power itself.
Theoretically, when plate lenses are placed into the capsular bag, the anterior capsule fibroses and applies end-to-end pressure on the plates, which vaults posteriorly and the optic comes to lie up against the vitreous face.
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 .
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.
This permits the capsule to mold the lens into a more strongly curved system (Table ], 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.