Intraocular lenses in cataract surgery in Chile: An updated review

Cataract surgery consists of removing the opaque natural lens and replacing its function with an intraocular lens (IOL). The first IOL successfully implanted in humans was done in 19119 with a polymethylmethacrylate (PMMA) IOL. New biocompatible materials such as hydrophilic acrylic, hydrophobic silicone, hydrophobic acrylic, among others, were developed, each with different advantages and disadvantages. Hydrophilic acrylic has a greater risk of posterior subcapsular opacity and dystrophic calcification, hydrophobic silicone opacifies in the presence of liquid silicone in the posterior segment, hydrophobic acrylic has more risk of glistening. The latter is the most widely used IOL in Chile due to its flexibility, low risk of dystrophic calcification and low risk of posterior subcapsular opacity. The greatest advances were made with new IOL designs. The traditional IOL is the monofocal IOL that later incorporates toricity. Multifocal diffractive bifocal and then trifocal IOLs appear giving spectacle independence but dysphotopsia. The Extended Depth of Focus (EDOF) technology allows exploring new optical properties, providing intermediate functional vision with minimal dysphotopsia. Today these characteristics are combined and we have a wide range of IOLs with different functionalities. This review aims to describe the performance of the different materials and designs, especially the most representative ones in our country. It also provides tools to define the most suitable IOL model for each patient and gives suggestions on formulas to calculate the spherocylindrical power in some special situations. Finally, a brief explanation of the future perspectives with the new accommodative IOLs under development.