Artificial Accommodation System - a new approach to restore the accommodative ability of the human eye

Restoring the accommodative ability of the human eye after a cataract operation or in case of presbyopia is a challenge in ophthalmology. An implantable mechatronic microsystem (Artificial Accommodation System) is a new approach to achieve this goal. It offers the advantage that a change in refractive power will neither depend on the force and kinematics of the ciliary muscle nor on the deformation capability of the lens' capsule. Requirements for the mechatronic microsystem are specified and its structure is presented. It consists of an adjustable optical element with an actuator, an information acquisition and -processing part, and an energy supply. Two fundamentally different system architectures are distinguished: An autonomous system derives the accommodation demand from environmental information, whereas a cooperative system derives the accommodation demand from efferent signals from the human body. Potentially suitable alternatives for the active-optical element comprise axially- or laterally shiftable refractive surfaces, a deformable elastic lens, a fluidic lens, an electrowetting lens or a liquid crystal lens. Their assets and drawbacks for the envisaged biomedical application are presented and compared.