Cataract surgery is done by removing the natural lens or crystalline lens of the eye that has been affected by the cataract. The metabolic changes undergone by the fibers of these crystalline lens throughout time is the one that results to the opacification, loss of transparency, and even loss of visual characteristics of the cataract condition. In cataract eye surgery, the cloudy lens is removed and a synthetic lens especially made to restore the transparency of lens is put in place of it. The surgery is often performed by ophthalmologists in a surgical center and uses local anesthesia like retrobulbar, peribulbar, or topical in both the removal and implanting of the lens, making the operation painless. Out of all the operations done, 90% were reported successful with a low 10% complication rate. The cataract standard cares known around the world includes day care, minimally invasive, quick post-operation recovery, and small incision phacoemulsification.

There are two main types of cataract eye surgery - namely the conventional extracapsular cataract extraction (ECCE) and phacoemulsification. Both types involve the intraocular lenses implanted in place of the infected natural lenses. One difference is that non-foldable lenses are used in ECCE while foldable lenses are the ones uses in the phaco method. Between the two, phaco is the most popularly done in the developed countries because of the expensive machines and disposable equipment it requires. The ECCE, on the other hand, are cheaper making it as the method done in most developing countries. In the phaco surgery, a machine equipped with an ultrasonic headpiece bearing a steel or titanium tip is used. The tip is made to vibrate to emulsify the lens material and raze the nucleus into smaller pieces. This fragmentation technique makes the emulsification easier and faster. After the phacoemulsification of the nucleus of the lens, a bimanual I-A machine is used to aspirate the peripheral and cortical material remained in the eye.

In the ECCE cataract eye surgery, manual expression of the lens is done through creating an incision in the cornea or the sclera part of the eye. Even though this method usually needs a bigger incision and stitches, its conventional technique is usually recommended for patients suffering from severe cataracts. This method also involves the whole removal of the natural lens while the posterior capsule is left in an intact state in order to allow its replacing in the intraocular lens. Because of the lack of new equipments, this kind of surgery takes longer to be completed though it is still considered as effective as the phaco method.