Modern extracapsular cataract extraction surgery involves removal of the lens fibers, which form the nucleus and cortex of the cataract, leaving the posterior epithelial capsule to hold the new artificial intraocular lens (IOL) and keep the vitreous humor away from the anterior chamber. Extracapsular techniques of cataract extraction surgery originally involved manual nuclear expression. Phacoemulsification is a mechanically assisted extracapsular technique of cataract extraction surgery.[1]
A cataract is illustrated in the image below.