The Tecnis Multifocal IOL

come the standard by which we evaluate the results of cataract and refractive surgery today. Contrast sensitivity testing has confirmed the decline in visual performance with age, and wavefront science has helped explain that this decline occurs because of increasing spherical aberration of the human lens. Since we have learned that the optical wavefront of the cornea remains stable throughout life, the lens has started to come into its own as the primary locus for refractive surgery. At the same time, laboratory studies of accommodation have now confirmed the essentials of Helmholtz’s theory and have clarified the pathophysiology of presbyopia.What remains is for optical scientists and materials engineers to design an intraocular lens (IOL) that provides unaberrated optical imagery at all focal distances. This lens must, therefore, compensate for any aberrations inherent in the cornea and either change shape and location or employ multifocal optics. Accommodative IOLs have now made their debut around the world (CrystaLens, Eyeonics and 1CU, HumanOptics). Clinical results indicate that restoration of accommodation can be achieved with axial movement of the lens optic [1]. However, concerns remain about the impact of long-term capsular fibrosis on the function of these designs. Flexible polymers designed for injection into a nearly intact capsular bag continue to show promise in animal studies [2]. These lens prototypes require extraction of the crystalline lens through a tiny capsulorrhexis and raise concerns about leakage of polymer in the case of YAG capsulotomy following the development of posterior or anterior capsular opacification. A unique approach now in laboratory development involves the utilization of a thermoplastic acrylic gel, which may be shaped into a thin rod and inserted into the capsular bag (SmartLens, Medennium). In the aqueous environment at body temperature it unfolds into a full-size flexible lens that adheres to the capsule and may restore accommodation. Another unique design involves the light-adjustable lens, a macromer matrix that polymerizes under ultraviolet radiation (LAL, Calhoun Vision). An injectable form of this material might enable surgeons to refill the capsular bag with a flexible substance and subsequently adjust the optical configuration to eliminate aberrations. While these accommodating designs show promise for both restoration of accommodation and elimination of aberrations, multifocal technology also offers an array of potential solutions. Multifocal intraocular lenses allow multiple focal distances independent of ciliary body function and capsular mechanics. Once securely placed in the capsular bag, the function of these lenses will not change or deteriorate. Additionally, multifocal lenses can be designed to take advantage of many innovations in IOL technology, which have The Tecnis Multifocal IOL