An intraocular lens (IOL) is an artificial optical lens implanted inside the eyeball to replace a removed natural lens or to correct refractive errors. An IOL consists of an optical part (5-7 mm in diameter) made of biocompatible materials such as acrylic, silicone or PMMA (polymethylmethacrylate), and haptics - support elements that stabilise the lens in the correct position. Most modern lenses are of the foldable type, allowing them to be implanted through a small corneal incision 2-3 mm wide, after which they unfold inside the eye reaching their full size.
Intraocular lenses are classified according to the location of implantation into: posterior chamber (most commonly used, placed in the lens pouch or ciliary groove), anterior chamber (implanted in the anterior chamber) and iris-fixed. In terms of optical function, a distinction is made between monofocal (monofocal, corrects vision at one distance), multifocal and trifocal (multifocal, allows vision at different distances), toric (corrects astigmatism) and EDOF (extended depth of focus). Modern premium lenses can combine several functions, e.g. multifocal toric lenses, and have additional properties such as blue light filtering or spherical aberration compensation to optimise the quality of post-operative vision and reduce dependence on spectacles.