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 Ain 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.