Ultrasound-Energy Consumption During Phases of Phacoemulsification of Nuclear Cataracts Using Femtosecond Laser: A Comparative Study

Purpose: To compare ultrasound (US) energy utilized in different phases of nuclear cataract removal in femtosecond laser-assisted cataract surgery (FLACS) with conventional phacoemulsification surgery (CPS) in relation to different nuclear densities. Methods: A prospective nonrandomized comparative study was conducted at AM Shams University and Al Watany Eye Hospital, Cairo, Egypt on 250 eyes with senile nuclear cataracts (NCs) of different nuclear densities (1-6). Eyes were divided into two groups - FLACS and CPS - and each group was subdivided according to cataract density into subgroups A (NC 1-2), B (NC 3-4) and C (NC 5-6). sextant-softened fragmentation patterns were assessed in the FLACS group and the quick-chop technique used in the CPS group. US energy required for nucleus cracking (EFX split) and for quadrant removal (EFX quadrant) was recorded. Results: Total eyes included in the FLACS and CPS groups were 117 and 133, respectively. No significant differences between the groups for EFX quadrant and EFX split groups were observed (P=0.18 and P=0.49, respectively). For subgroup A, no significant difference was found between FLACS and CPS on EFX split (P=0.08) and EFX quadrant (P=0.49). For subgroup B, significantly lower values of EFX split (P=0.0001) and EFX quadrant (P<0.0001) were obtained with FLACS than CPS. For subgroup C, no significant difference was found for EFX split (P=0.86), however, EFX quadrant was significantly lower in the FLACS group (P=0.05). Conclusion: FLACS lowers US energy utilized during quadrant removal at different nuclear densities, with highest significance in medium-density nuclear cataracts. Nucleus cracking by femtosecond laser is less effective in very hard cataracts. However, femtosecond-laser softening of hard nuclei is capable of of US-energy reduction during quadrant removal.