A cataract is a clouding of the crystalline lens of the eye. Because it is not a film over-the lens it can't be removed with a laser or eye drops. Surgery is the only way to treat cataract. Surgery involves removing the cloudy lens and replacing it with a plastic intraocular lens (IOL). Both steps are generally done at the same time, although the implant can be placed later. Standard monofocal lenses are generally used to replace the power of the lenses removed during cataract surgery. Newer premium lenses that are designed to correct either astigmatism or presbyopia and, in the process, make people less dependent on glasses, are now an option for some patients. The decision to place a premium IOL, as opposed to a standard lens, is dictated by patient preference and pre-operative clinical findings.
Months or years after cataract surgery, the posterior capsule (behind the intraocular lens) may become cloudy. If this happens, the surgeon will perform a simple laser procedure to make an opening in it. This opening allows light to enter through, restoring clear vision.