الفهرس | Only 14 pages are availabe for public view |
Abstract Cataract is the most common treatable cause of blindness in the world and surgical removal of hard cataract presents special challenges to the surgeon. There are strong relation between amount of ultrasound energy used and corneal endothelial loss during phacoemulsificstion with different degrees of nuclear density. To reduce total phaco time and energy placed into the eye, a mechanical method of breaking the nucleus, such as chopping, must be used. Additionally, switching from a four-quadrant divide-and-conquer technique to chopping approach avoids using single-handed phacoemulsification. All chopping methods are conceptually divided into two general categories of chopping; horizontal and vertical. Both share the same benefit of being able to fragment the nucleus manually, but they accomplish this objective in different ways. In Nagahara chop, peripheral chopping starts at the lens equator which is based on the natural cleavage planes that exist in the nucleus, the nucleus is held with the phaco tip with high suction and chopped into smaller pieces with a sharp chopper. But in vertical chopping the two instrument tips move towards each other in the vertical plane in order to create the fracture. Such advanced surgeries need an intensive training especially for novice surgeons, because that work needs high skills to control the appropriate chopping and to avoid complications as much as possible. |