Development of a ciliary muscle-driven accommodating intraocular lens

PURPOSE: 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.

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

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.