A cataract is a clouding that develops in the crystalline lens of the eye  or in its envelope  (lens capsule), varying in degree from slight to complete opacity and obstructing the passage of light.  Cataracts typically progress slowly to cause vision loss, and are potentially blinding if untreated. The condition usually affects both eyes, but almost always one eye is affected earlier than the other. Many patients' first symptoms are strong glare from lights and small light sources at night, along with reduced acuity at low light levels.

Cataract surgery is the removal of the natura lens of the eye  that has developed an opacification, which is referred to as a cataract. The cataract is removed using an ultrasound probe that enters the eye through a tiny 2 millimeter incision in the cornea. The cataract is broken up and vacuumed out and then an intraocular lens implant is placed. This is a outpatient procedure performed  in an ambulatory setting (in a surgical center or hospital) using local anesthesia (either topical, peribulbar, or retrobulbar), usually causing little or no discomfort to the patient.

Months to years after cataract surgery, changes on the posterior capsule (which is left to suport the intraoculars lens) are observed. The posterior capsule shows sings of thickening, opacification and clouding. This can compromise visual acuity.

With the use of a laser, the capsule can be disrupt (Posterior Capsulotomy) clearing the central portion of the opacified lens capsule. This creates a clear central visual axis for improving visual acuity . This is a outpatient procedure.