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

Abstract

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.

Cumulative dissipated energy in eyes with and without corneal opacity

“…Lower CDE represents lower ultrasonic energy use during phacoemulsification, and it is considered a lower risk of trauma in anterior chamber structures and corneal endothelium [ 14 ]. Corneal endothelial cell loss is associated with clinically detectable corneal oedema, which can be permanent, and results from heat produced by phaco tip, and free radicals and fluid turbulence produced during ultrasonic energy delivering [ 17 ]. To monitor CDE and to know the effects of different conditions on CDE is important to prevent potential ultrasonic energy associated corneal complications in phacoemulsification surgery.…”

Management of inflammation after the cataract surgery

“…Since the introduction of femtosecond laser in the cataract surgery in the 2010, studies reported its advantages when compared with conventional phacoemulsification from which maybe the most important one when considering postoperative inflammation was reduced phacoemulsification time and energy [17–19]. Cumulative dispersed energy was significantly lower in the FLACS group when compared with conventional phacoemulsification not only in retrospective [20] and comparative studies [21] but also in randomized clinical trials [22,23].…”

Phacoemulsification: Proposals for Improvement in Its Application

“…We compared the amount of ultrasound energy and the volume of irrigation [6] (measuring the effective phacoemulsification time (EPT), which indicates the ultrasound energy, and the use of balanced salt solution (BSS), which indicates the volume of irrigation) to indirectly estimate endothelial damage. We found a reduction in the effective phacoemulsification time, but no influence on the use of BSS, which was able to indirectly estimate endothelial damage [3].…”

“…Together with the mechanical effect generated by moving the phaco handpiece over the lens material [20,82], small bubbles are formed in the liquid environment in which the U/S is applied. A large energy release occurs as the bubbles collapse due to the physical phenomenon called cavitation [6,7]. Cavitation could be defined as the growth, oscillation, and collapse of micrometer-sized bubbles in liquids under the influence of an acoustic field [7].…”

“…Phacoemulsification is currently the most widely used surgical method for intraocular lens extraction and is one of the safest and most effective procedures for this purpose [5,6]. The word comes from the Greek ϕακoς (phakos), an ancient technical prefix that alludes to a lens and was used in medicine in ancient times to refer to the crystalline lens.…”