Benefits and barriers of accommodating intraocular lenses.

Abstract

Presbyopia and cataract development are changes that ubiquitously affect the aging population. Considerable effort has been made in the development of intraocular lenses (IOLs) that allow correction of presbyopia postoperatively. The purpose of this review is to examine the benefits and barriers of accommodating IOLs, with a focus on emerging technologies. True accommodation of an IOL involves a dynamic increase in dioptric power to affect a shift from distance to intermediate or near focus. The Crystalens (Crystalens Bausch and Lomb, Inc., Rochester, NY, USA) was the first IOL labeled by the FDA as an accommodating IOL. Further studies have suggested that the Crystalens and several other single optic presbyopia-correcting IOLs may be providing improved intermediate or near vision predominantly through pseudoaccommodative mechanisms, in addition to small changes in axial translation. In light of these findings, a more objective demonstration of accommodation is now required for an IOL to have an accommodative label. Newer technology accommodating IOLs in development have embraced design strategies using dual optics, shape-changing optics, and IOLs with dynamic changes in refractive index. Prevention and treatment algorithms for capsular contraction syndromes unique to Crystalens and Trulign IOL designs will be discussed. Accommodating IOLs that are in current use are constrained by their low and varied amplitude of accommodation. Such limitations may be circumvented in the future by accommodative design strategies that rely more on shape-related changes in the surfaces of the IOLs or in dynamic changes in refractive index than by forward translation alone.