The use of a flexible IOL enables the lens to be rolled for insertion into the capsular bag through a very small incision, thus avoiding the need for stitches. This procedure usually takes less than 30 minutes in the hands of an experienced ophthalmologist, and the recovery period is about 2–3 weeks. After surgery, patients should avoid strenuous exercise or anything else that significantly increases blood pressure. They should visit their ophthalmologists regularly for 3 weeks to monitor the implants. IOL implantation carries several risks associated with eye surgeries, such as infection, loosening of the lens, lens rotation, inflammation and nighttime halos, but a systematic review of studies has determined that the procedure is safer than conventional laser eye treatment. Though IOLs enable many patients to have reduced dependence on glasses, most patients still rely on glasses for certain activities, such as reading. These reading glasses may be avoided if Multifocal IOLs, Trifocal IOLs or EDOF lenses are used. Medical uses
Intraocular lenses have been used since 1999 for correcting larger errors in near-sighted, far-sighted, and astigmatic eyes. This type of IOL is also called phakic intraocular lens (PIOL), as it is implanted without removing the patients natural crystalline lens.Phakic IOL appear to be less dangerous than excimer laser surgery (LASIK) in those with significant nearsightedness.More commonly IOLs are implanted via Clear Lens Extraction And Replacement (CLEAR) surgery.
Manifest refraction is the familiar test where the eye doctor rotates lenses in front of the eye, asking the patient, "Which is better (or clearer), this one or this one?" Corneal topography is considered a more quantitative test, and for purposes of aligning a toric IOL, most surgeons use a measurement called simulated keratometry (SimK), which is calculated by the internal programming of the corneal topography machine, to determine the astigmatic meridian on the surface of the cornea. The astigmatic meridian can also be identified using corneal wavefront technology or paraxial curvature matching. Type of surgery
Implants with or without removal of natural crystalline
Phakia is the presence of the natural crystalline lenses. Phakic IOL (PIOL) refers to an intraocular lens implanted without removal of the patients original crystalline lens, and this is performed solely to correct refractive error in the presence of a clear crystalline lens. Aphakia is the absence of the natural crystalline lens. The aphakic state is usually due to surgery to remove a cataractous lens, but post-surgical aphakia is rare nowadays because of the ubiquity of intraocular lenses. Rarely, aphakia can be post-traumatic or congenital in nature. Aphakic IOL refers to a lens implanted secondarily in an eye already aphakic from previous surgery or trauma some time ago. Pseudophakia is the substitution of the natural crystalline lens with an IOL, as is often done after cataract extraction or to correct refractive error.