Essentially, there are two ways of removing cataracts: the traditional way of removing the whole cataract in one piece through a larger incision of 6–11mm and the newer way of first dividing the cataract into smaller pieces and then sucking them out through a much smaller 2–2.5mm incision.
Phacoemulsification (Phaco) uses ultrasound energy to help soften and then remove the cataract. This is the a well-established technique in cataract surgery and most cataracts are performed this way. It has been shown to be safe, predictable and gives excellent visual outcomes with low residual refractive errors.
Phaco Prechop is a supplementary technique to phaco in which the hard lens centre or nucleus is first divided into halves and then quadrants for easier removal by the ultrasound probe thereby reducing the amount of ultrasound energy dispersed in the eye. Grooving the nucleus as seen in the phaco picture above is not necessary.
Perfectly circular femtosecond laser opening of the anterior lens capsule and precise quartering of the cataract nucleus facilitate easier removal with less use of ultrasound energy
Other ways of reducing the size of the cataract nucleus so that a small 2.5mm incision can be used involve snares, loops or wires to divide a nucleus and whilst in the hands of trained surgeons can they deliver good results, they have not been widely adopted.