One-piece bifocal intraocular lens construction

Abstract

A rigid bifocal intraocular lens (60) for use as an artificial lens implant is disclosed. In one embodiment, the intraocular lens has a rigid lens body (61) having a chord (61a) and first and second lens portions (62) and (63). The first lens portion (61) has a focal length and the second lens portion (63) has a focal length different from the focal length of the first lens portion (62). The first lens portion (62) is positioned on one side of the chord (61a) and the second lens portion (63) is positioned on the other side of the chord (61a). The first and second lens portions (62 and 63) form an integral, one-piece optical lens body (61) with the first and second lens portions being non-movable with respect to one another. In another embodiment the rigid lens body has a first central circular lens portion and a second outer annular lens portion. In a preferred form of this embodiment the inner, circular lens has a diameter of a between about 1.8 millimeters and about 2.0 millimeters, with the outer annular lens portion having a diameter of between about 6 millimeters and 7 millimeters. A preferred corrective power for the lenses used in the above-referenced embodiments is between about +15 and about +25 diopters for a distance-viewing lens portion, and a corrective power for a near-viewing portion of between about +3 and +4 diopters greater than the corrective power of the distance-viewing portion. Preferably, the lens portions are formed from molding in a manner avoiding introduction of any substantial refractive index gradient in the lens material.