Other Intraocular Lens Innovations on the Horizon
In addition to single-plate accommodating IOLs, which are thought to work via lens effectivity secondary to a change in the position of the optic in the eye, lenses with dual-optic elements connected by a system of springlike struts have been developed and are under clinical investigation (Fig 9-9). During accommodation, the lens system confined within the capsular bag undergoes a change in the separation of the 2 optics, resulting in increased effective lens power. The lens can be implanted into the eye through a 3.5-mm incision.
Another type of lens is made from a thermoplastic acrylic gel that can be customized to any size, shape, or power specified by the physician. The hydrophobic acrylic material is chemically bonded to wax, which melts inside the eye at body temperature and allows the predetermined shape and power of the material to emerge. Theoretically, compression of this pliable lens by the capsular bag allows adjustment of its effective power in a manner analogous to the way the crystalline lens adjusts. Examples of deformable IOLs in preliminary stages of development are the FlexOptic IOL (Abbott Medical Optics), FluidVision IOL (PowerVision, Belmont, CA), and NuLens accommodating IOL (NuLens Ltd, Herzliya Pituach, Israel). The NuLens changes its power rather than its position in the eye. It incorporates a small chamber of silicone gel and a posterior piston with an aperture.
In addition, flexible polymers are being designed for injection into a nearly intact capsular bag following extraction of the crystalline lens through a tiny, laterally placed capsulorrhexis.
The Light Adjustable Lens (LAL) (Calhoun Vision, Pasadena, CA) is made from a macromer silicone matrix with smaller, embedded photosensitive molecules that allow for postoperative customization of the power via tunable ultraviolet light treatment (see Chapter 8 for more details).
Figure 9-9 Clinical photograph of an implanted dual-optic accommodating intraocular lens, which has a high-plus anterior optic connected by spring haptics to a posterior optic with variable negative power. The 3-dimensional design mimics the natural lens, and its response to the contraction and relaxation of the ciliary muscle increases paraxial power and provides accommodation.
(Courtesy of Ivan Ossma, MD.)
Excerpted from BCSC 2020-2021 series: Section 13 - Refractive Surgery. For more information and to purchase the entire series, please visit https://www.aao.org/bcsc.