Charles F. Prentice award lecture 2008: surgical correction of presbyopia with intraocular lenses designed to accommodate.
Surgical restoration of accommodation with accommodating intra-ocular lenses (A-IOLs) presents a complex set of problems involving the design of the prosthetic mechanism. A variety of designs are currently employed that either translate the A-IOL toward the cornea along the sagittal axis, shear two lens components laterally, or deform lens shape to change dioptric power of the eye during attempts to accommodate. Effective biomechanical properties (elasticity and viscosity) of these lenses depend on both material properties and structural design of the A-IOL. Inevitable mismatches between the neuromuscular control of accommodation and the effective biomechanical properties of the prosthetic lens could lead to either unstable oscillations or sluggishness of dynamic accommodation; however, optimal dynamic responses may possibly be restored by neural recalibration. A model of dynamic accommodation is used to predict the consequences of these mismatches on dynamic accommodation, and reverse engineering is used to test the feasibility of neuromuscular recalibration. Empirical measures verify that neuromuscular adaptation of dynamic accommodation is possible in response to optically simulated increases and decreases of ocular-lens stiffness. Other design issues for A-IOLs include stability of optical properties, aberrations and image quality, and interactions of restored accommodation with binocular eye alignment (the near response).
Schor
Clifton M
CM
School of Optometry, University of California, Berkeley, Berkeley, California 94720-2020, USA. schor@berkeley.edu
D000065:Accommodation, Ocular; D000222:Adaptation, Physiological; D000375:Aging; D001363:Awards and Prizes; D002138:Calibration; D018450:Disease Progression; D004867:Equipment Design; D006801:Humans; D019654:Lens Implantation, Intraocular; D007910:Lenses, Intraocular; D008954:Models, Biological; D009469:Neuromuscular Junction / Q000503:physiopathology; D011305:Presbyopia / Q000503:physiopathology* / Q000601:surgery*