Development of a repeatedly adjustable intraocular lens

Abstract

Purpose: To provide a variable-focus intraocular lens (IOL) that is able to adjust repeatedly and reversibly. Setting: University of Missouri-Rolla, Rolla, and Eggleston Adjustable Lens, St. Louis, Missouri, USA. Methods: An adjustable IOL based on a mechanically adjustable design has been developed. Prototypes were fabricated from traditional Perspex ® CQ poly(methyl methacrylate) (PMMA) provided off the shelf by a current IOL manufacturer. The prototypes have undergone proof-of-concept testing per the requirements of National Institutes of Health grant 1 R41 EY13482–01, with specific attention to the feasibility and safety of continuing development of the lens with in vivo trials. The experimental results presented focus on operational force measurements. Results: Prototype lenses were produced consistently. Operational force measurements indicated that use of the mechanical adjustment mechanism is viable for an adjustable IOL and provides repeated adjustments over time. Turning forces exhibited by the prototypes were low enough to suggest that operation of this adjustable IOL will not damage the capsular bag or ciliary body of the eye, a potential concern in using this design. Biocompatibility and optical quality of the prototype lenses are ensured by use of traditional Perspex CQ PMMA. Conclusions: The mechanically adjustable IOL provides a feasible and promising means of confronting postoperative refractive errors and the changing desires of patients. The viability of this IOL design has been proven, and results suggest that operation of the lens is safe enough to pursue in vivo trials. Evaluation of the biocompatibility of the lens architecture as well as the ultimate goal of noninvasive adjustment using this model are reported in a companion article.