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Harilaos S Ginis, Corinne Wittmer, Theodore Werblin, Carsten Laue; Development of a two-component intraocular lens system for cataract surgery. Invest. Ophthalmol. Vis. Sci. 2017;58(8):2727.
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Despite the increasing accuracy of measurement devices, surgical technique and calculation methods, the refractive accuracy of cataract surgery remains inadequate. We report on the design of a two-component intraocular lens system that facilitates refractive enhancement surgery by means of surgical exchange of one of the components.
The lens system consists of a hydrophobic biconvex lens that serves as a base lens to which an additional hydrophilic meniscus lens is attahed anteriorly. The base lens is implanted in the capsular bag while the front lens is outside of the capsule and therefore easily accessible if an exchange is required. Having four refractive surfaces and two different materials allows the optimization of the lens for central and peripheral optical performance. Modelling was carried out using ZEMAX (Zemax, LLC, Kirkland, USA) ray tracing software, both for the isolated and the implanted lens system. Formulas for the lens power calculation for primary and enhancement surgery were developed.
The optimized lens design has its power balanced between the two elements. This approach allows the reduction of spherical aberration for a range of system powers ranging from 10 to 30 Diopters. The optimized design has off-axis astigmatism and coma that are comparable to those of phakic eyes. For a 20 Diopter lens, the Petzval field curvature corresponds to approximately 1 Diopter of myopia at a field angle of 30 degrees, if implanted in an eye with spherical retina and an axial length of 23.3mm.
The lens design is characterized by minimized spherical aberration throughout the examined range of total lens powers (10-30Diopters). The two-component system performs adequately well both on and off-axis when compared with the phakic eye. The two-component lens may be particularly applicable in cases where a lens exchange on refractive grounds is very likely (e.g. pediatric cataract) or in any case that fine-tuning the eye's refraction postoperatively is desirable.
This is an abstract that was submitted for the 2017 ARVO Annual Meeting, held in Baltimore, MD, May 7-11, 2017.
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