Theoretical Analysis of Accommodation Amplitude and Ametropia Correction by Varying Refractive Index in Phaco-Ersatz

Abstract

Phaco-Ersatz is a surgical procedure for restoring accommodation in which the presbyopic crystalline lens is replaced by a flexible polymer gel in the lens capsule. We assessed the feasibility of simultaneously correcting ametropia while restoring accommodation using Phaco-Ersatz by utilizing polymer gel of the appropriate refractive index. Computation results using paraxial equations and ray tracing on two model eyes indicate that although this approach might be feasible for the hypermetrope, its usefulness for correcting myopia is limited, principally due to significant reductions in the resultant amplitude of accommodation.

Model of accommodation: Contributions of lens geometry and mechanical properties to the development of presbyopia

“…In part C, the effect of changing the optical properties of the lens was examined. Ho et al 32 suggest that replacing existing lens material with material of a uniform index of refraction can be used in the correction of presbyopia. To test this hypothesis, the nucleus and cortex of each of our baseline lens models was replaced with a material of the same mechanical properties but a different, uniform refractive index.…”

Biocompatibility of poloxamer hydrogel as an injectable intraocular lens

“…[1][2][3][4][5][6][7][8][9][10][11][12] Silicone has been used as a lens refilling material; however, it has a low specific gravity and a high rate of posterior capsule opacification. We used a new material for an injectable IOL to prevent the problems associated with silicone.…”

Accommodating intraocular lenses: a review of design concepts, usage and assessment methods

“…A lower index material, which may be used to correct myopic refractive errors would limit the potential accommodative ability. 131 The SmartIOL has been implanted into human cadaver eyes but clinical trials have yet to begin. 129 An additional strategy to provide a high amplitude of accommodation with an IOL has been developed by Alan Glazier in the United States, who proposed the use of fluids with differing refractive indices contained within the lens optic.…”