Abstract
Abstract: :
Purpose: To calculate the pseudo–accommodation amplitude provided by translating accommodating intraocular lenses (A–IOL) that use one or two optical elements. Methods: Two optical models of the eye with A–IOL were developed based on the Escudero–Navarro eye model (1998). The first model assumes that the A–IOL elements are thin and uses paraxial calculations to derive an expression for the change in optical power as a function of implant displacement. The second model uses finite ray–tracing with optical design software (Zeemax) and takes into account the thickness and shape of the A–IOL elements. The power of the single element A–IOL was calculated to produce a focus at infinity when the implant is located posteriorly in the capsular bag. The 2–element IOL consisted of a fixed negative lens located posteriorly in the capsular bag and an anterior positive lens that moves forward during pseudo–accommodation. The 2–element A–IOL was calculated to produce a focus at infinity when the lenses are in contact. Results: Both one– and two– element lens produce a linear increase in power as a function of axial position, with a slope a slope of 1.15 D/mm for the single–element A–IOL. The change in power produced by the 2 element A–IOL increases approximately linearly as the power of the moving element increases, with a maximum slope of 1.2D/mm predicted by finite ray–tracing, and 2.5D/mm according to the paraxial calculations. Conclusions: Optical modeling demonstrates that both single– and two– element A–IOLs produce a pseudo–accommodation amplitude of approximately 1D per mm change in axial position. The change in power produced by a 2–element A–IOL is constrained by the thickness of the elements. Support: EY14225–01; Vision CRC, Sydney, Australia; Florida Lions Eye Bank; Henri and Flore Lesieur Foundation; Research to Prevent Blindness, NY, NY.
Keywords: refractive surgery: other technologies • computational modeling