The EyeDIFF Intraocular Lens

Abstract

The goal of a multifocal IOL is to provide functional vision at different distances to minimise the use of glasses. Most studies support that these IOLs offer good distance and near visual acuity (Cochener et al., Clin Ophthalmol 5:45–56, 2011). However, it is well known that traditional diffractive bifocal multifocal IOLs report poor scores for intermediate vision, which correlates with worse intermediate visual acuity and a high percentage of patients who wear glasses for seeing objects at intermediate distance (Alfonso et al., J Cataract Refract Surg 36:733–39, 2010). The poor performance at intermediate vision is due to their optical design where light is distributed in two major peaks, zero order for far and first order for near vision. Recent advances in diffractive multifocal IOLs technology offer a new alternative for those desiring vision at distance, intermediate and near (Anton et al., Graefes Arch Clin Exp Ophthalmol 252:539–44, 2014). This chapter describes a new IOL based on 100 % diffractive technology, providing an extended range of clear vision at all distances. The full-range multifocal lens makes use of both refractive and diffractive optics. Consequently, the design of the lens is governed by refractive and diffractive considerations and their interrelations. The diffractive power of the zones gradually decreases across each zone in the radial direction r (throughout this specification, underlined italic symbols represent vector) as illustrated in Fig. 15.1 above. Diffractive power of the zone is the first-order diffractive power. The advantage of gradually decreasing diffractive power is that it provides intermediate vision along near and far vision. It is achieved by decreasing diffractive power across each zone and changing the diffraction pattern.