In a prospective randomized study , conventional phacoemulsification with a 2.8-mm clear corneal incision using a disposable keratome was performed in 20 eyes of 20 patients ( manual group ) , and femtosecond laser-assisted cataract surgery with a 2.8-mm biplanar clear corneal tunnel created by a femtosecond laser ( LenSx ; Alcon Laboratories , Inc. , Aliso Viejo , CA ) was performed in 20 eyes of 20 patients ( femtosecond laser group ) .