Development of a ciliary muscle-driven accommodating intraocular lens

To develop a ciliary muscle-driven accommodating intraocular lens (IOL) that has a large and predictable range of variable power as a step toward spectacle independence.

Department of Physics and Medical Technology, VU University Medical Center, Amsterdam, The Netherlands.

A concept IOL that has a rotating focus mechanism and a mechanical frame that can operate within the range of ciliary muscle contraction of a typical 60-year-old human eye was designed. Prototypes were made to test the IOL's mechanical performance in an enucleated pig's eye using a laboratory lens-stretching device that mimics the action of the human ciliary muscle. Changes in focal length during stretching were measured by laser-based ray tracing and a videocamera system. To rotate the 2 lenses in the IOL with variable optical power, a frame that allows the displacement and force of the ciliary muscle to be transferred by the capsular bag was designed.

Ray tracing showed that the modulation transfer function (MTF) of the IOL in different accommodative states did not deviate to a great extent from the MTF of a monofocal IOL. During stretching experiments, the prototype IOL achieved 8.0 diopters of accommodation.

Evaluation of an accommodating IOL that meets the requirements for a spectacle-independent solution to presbyopia showed that the mechanical and optical designs must be further optimized to improve optical quality and functionality.