Three-Piece Intraocular Lenses
Intraocular lenses come in two major design varieties, single-piece and 3-piece. In contrast to single-piece IOLs which are crafted from a single piece of material with the haptics intrinsically attached to the optic, three-piece lenses have the optic manufactured separately from the haptics with the haptics then implanted into the optic material. Haptics may extend from the optic at various angles, usually between 0°–10° of angulation. Haptics play a role in the position of the IOL after implantation. Three-piece foldable IOLs have haptics of a much more rigid material, such as PMMA or polyamide, which have considerable outward compression force compared to that of single-piece foldable IOLs. The haptics are much thinner and are much better tolerated in the sulcus than the bulky, single-piece haptics. However, they are much easier to damage during IOL insertion, and recent reports associate 3-piece IOLs with greater degrees of tilt as a result.