A monofocal IOL is an intraocular lens with a fixed focus for one distance. Monofocal IOLs can be selected for near, mod-distance, or distant focus, but only one of these three can be selected. an IOL focuses light that comes into your eye (like your own natural lens) through your cornea and pupil and onto your retina. IOLs are constructed of silcone or acrylic and coated with a material to protect your eyes from UV rays. Just like prescription eyewear and contact lenses, IOLs come in different focusing powers which is determined by the measurements take by your ophthalmologist.