One of the most important areas in minimally invasive surgery is phacoemulsification surgery, which has revolutionized cataract surgery in the recent years. In phacoemulsification surgery, an ultrasound probe is inserted into the eye. Ultrasound energy is applied to the crystalline lens of the eye to emulsify it. The emulsified material is then removed from the eye using vacuum. The capsular bag is left behind for the implantation of an artificial intraocular lens replacing the cataractous crystalline lens.
Phacoemulsification allows the relatively large cataract to be removed via a small incision. However, the ultrasound energy used may damage the cornea, which is the transparent ‘cover’ of the eye, causing the loss of the endothelial cell layer. Significant loss of endothelial cells may lead to a later complication known as bullous keratopathy requiring corneal transplant. Bullous keratopathy is now the commonest indication of corneal transplant in many parts of the world.
One of the good surgical techniques which helped to reduce endothelial cell loss is the use of mechanical forces emanating from a phaco probe tip. These forces are better localised than ultrasound energy. Mechanical forces used include techniques known as phaco-chop, and using a second instrument to manually break up small pieces of lens material and the removal of these fragments using high vacuum. The lower the mechanical breaking force, the higher the vacuum force will be required. However, high vacuum has its dangers. It can suck in the posterior capsule thereby rupturing it. Rupture of the posterior capsule can lead to serious complications such as retinal detachment and intraocular lens displacement.