#6: Intraocular Lenses

The first implantable intraocular lens (IOL) was surgically inserted nearly 70 years ago by Sir Harold Ridley at St. Thomas Hospital in London. It took more than two decades for the use of polymethyl methacrylate (PMMA) IOLs to catch on, but by the 1970s, PMMA IOLs were routinely implanted after cataract surgery.

The downside, of course, with PMMA IOLs is their rigid nature, which requires an incision that is at least as large as the lens itself. The introduction of the flexible/foldable IOL in 1989 revolutionized the implantation process, allowing surgeons to make smaller incisions and eliminate the need for stitches following the procedure. Currently available foldable IOLs can be classified according to their optic material – silicone, hydrophilic acrylic, hydrophobic acrylic, and collagen/hydroxy ethyl methacrylate-copolymer-based. Almost all IOLs have ultraviolet-blocking chromophores. 

The Tecnis(R) Symfony lOL is among the newer options available for implantation during cataract surgery.Today, more than 6 million IOLs are implanted annually worldwide, and a number of technologic advances have given surgeons and patients a wealth of options from which to choose. Conventional monofocal IOLs as well as premium aspheric, toric, and multifocal IOLs, are among the current options. The choice of which IOL to implant during surgery often takes into account factors such as patient age, baseline visual acuity, the presence or absence of astigmatism, post-surgical goals, as well as financial considerations. A careful preoperative workup is also required that includes A-scan ultrasonography or optical biometry and retinal OCT to identify any coexisting pathology.

Advances in the design of IOLs have helped to make cataract surgery one of the safest procedures in eye care. Complications specific to IOLs occur infrequently and vary depending on the design and material of the particular IOL.