Comparison of Ultrasonic Energy Expenditures and Corneal Endothelial Cell Density Reductions During Modulated and Non-Modulated Phacoemulsification

Comparison of cumulative dispersed energy between conventional phacoemulsification and femtosecond laser-assisted cataract surgery with two different lens fragmentation patterns

The purpose of the study is to compare the total ultrasound power used between eyes undergoing different lens fragmentation patterns of femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification surgery (CPS). A total of 506 patient eyes underwent preoperative grading of lens opacity using the Lens Opacity Classification System III (LOCSIII). The eyes were divided into two subgroups: subgroup 1 had a LOCSIII grade of 1-3, and subgroup 2 had a LOCSIII grade of 4-6. The eyes underwent FLACS (LenSx) for clear corneal wound, capsulotomy, and lens fragmentation. Either a grid pattern or radial pattern was used for lens fragmentation. The eyes received one of the following three treatments: (1) CPS without femtosecond laser assistant, (2) FLACS with a grid pattern (FGP) lens fragment, or (3) FLACS with a quadrant pattern (FQP) lens fragment. The mean cumulative dispersed energy (CDE) for each subgroup and treatment was evaluated. The mean CDE was lower in the two FLACS groups (1.21±1.91 in FGP and 1.22±1.92 in FQP) than that in the CPG group (2.67±2.84). In subgroup 1, CDE was higher in the CPG group (1.54±1.18) as compared with the FLACS groups (0.16±0.31 in FGP and 0.74±1.17 in FQP; P<0.001). In subgroup 2, CDE was higher in the CPG (6.47±3.46) as compared with the FLACS groups (2.74±2.21 in FGP and 5.34±2.17 in FQP; P<0.001). CDE was lower in the two FLACS groups than that in the CPS group, and CDE was the lowest with FGP in both subgroups 1 and 2.

Comparison of surgical parameters using different lens fragmentation patterns in eyes undergoing laser-assisted cataract surgery

PURPOSE

To compare surgical parameters among eyes undergoing laser-assisted cataract surgery (LACS) using different lens fragmentation patterns (LFP).

METHODS

Prospective, randomized, unmasked clinical trial. One-hundred eyes underwent LACS and were randomly assigned to 1 of 3 LFP treatment groups: (1) laser capsulotomy only; no lens fragmentation (NLF) (n = 34); (2) three-plane chop (TPC) (n = 33); and, (3) pie-cut pattern (PCP) fragmentation (n = 33). Prechop phacoemulsification (PHACO) was performed on all eyes using the same femtosecond (FS) laser and active-fluidics PHACO machine.

MAIN OUTCOME MEASURES

FS laser dock time (s), PHACO time (s), PHACO power (%), cumulative dissipated energy (CDE) (%-s), irrigating fluid volume, and operative time.

RESULTS

The 3 treatment groups were comparable in terms of patient age (P = 0.164) and nuclear density (P = 0.669). FS dock time was higher in the PCP group (184.18 ± 25.86) compared to the TPC (145.09 ± 14.15) group (P < 0.001). PHACO time was significantly shorter in the PCP (23.19 ± 17.20 s) compared to TPC (35.27 ± 17.70) and NLF (46.15 ± 23.72) groups (P < 0.001). PHACO power was lower in the PCP (11.81 ± 3.71) compared to the NLF (14.41 ± 1.88) and TPC (14.04 ± 2.46) groups (P < 0.001). CDE was lower in the PCP (2.85 ± 2.32) compared to NLF (6.55 ± 3.32) and TPC (6.55 ± 5.45) groups (P < 0.001). Fluid volumes and operative times were similar.

CONCLUSION

LFP can influence PHACO surgical parameters. Extensive fragmentation patterns such as PCP appear to lower PHACO time, power, and CDE and may potentially reduce the risk of PHACO related complications.