Several types of IOLs are used for cataract surgery. The most common is the monofocal IOL, which allows for focus at a fixed distance. A disadvantage of the monofocal IOL is the requirement of the patient to wear corrective lenses after cataract surgery. Monofocal lenses include both spheric and aspheric IOLs. The difference between the two is in the surface of the lens, whether it is spherical or aspherical. This curvature is related to the correction of spherical aberration, or the excessive refractive power of the cornea at its periphery. Aspheric lenses are generally considered to be superior. They have been shown to produce clearer vision and greater contrast sensitivity. In the Nordic region 90% of the market is aspheric. Southern Europe uses more spherical lenses while Germany uses more aspheric. However, the use of aspheric IOLs involves a trade-off, with conventional (spheric) IOLs having been shown to produce better depth of focus and near vision.

LASERs, which stands for Light Amplification (by) Stimulated Emission (of) Radiation, were developed in 1960 by Theodore Maiman. Lasers were quickly adopted for ophthalmology with the first instance of their clinical use appearing in 1963. Over the last 50 years ophthalmic lasers have proliferated in both types of lasers and indications. Despite this diversity, all lasers function on the same fundamental principles. Lasers are created when the electrons in atoms in special glasses, crystal or gases absorb energy from an electrical current or another laser and become excited/elevated to a higher energy state. Electron orbits are less stable at these higher energy states, thus energy is released in the form of a photon which allows the electron to return to its ground state. Photons are particles of light, however, what makes laser photons unique is that they are all of the same wavelength, directional, and coherent (meaning the crests and troughs of the light waves are aligned) whereas ordinary light comprises multiple wavelengths and is not coherent.

Ophthalmic viscosurgical devices (OVD) are viscoelastic solutions used in several eye surgeries. They are also referred to as viscoelastic agents. These fluids have had a great influence on both extracapsular and phacoemulsification surgeries and their use has decreased the incidence of corneal edema. The main task of the OVD is protecting the inner side of the cornea during surgery. It accomplishes this by maintaining a deep anterior chamber during anterior segment surgery. This space prevents contact with and possible damage to the endothelial cell layer on the inner side of the cornea and the surrounding ocular tissues. In addition OVDs help to push back the vitreous face in the event of a posterior capsule tear or a rent in the zonules all the while preventing formation of a flat chamber during surgery.

There are two main types of cataract surgeries, those that involve phacoemulsification and those that involve extracapsular cataract extraction. Phacoemulsification is the preferred and most common technique because it requires a smaller incision for cataract removal. The small incision necessitates the insertion of foldable artificial lenses known as intraocular lenses (IOLs).

Refractive errors can be corrected by procedures such as Phakic IOL implantation and Laser Assisted In-Situ Keratomileusis (LASIK). LASIK modifies corneal thickness; thus it is limited by the amount of corneal tissue that can be safely removed. If too much is removed, the cornea becomes too thin and weak, and bulging of the cornea could occur, which is a condition known as ectasia. Treatment of ectasia involves exchanging the cornea in a procedure called keratoplasty, which leaves the patient with very poor vision. Phakic IOL implantation has the advantage of being able to correct a higher degree of refractive error than LASIK. Even with these disadvantages, LASIK is the leading refractive surgery procedure because phakic IOL implantation is more expensive, and implantation of these lenses is a more invasive procedure.