Electron microscopy analysis of femtosecond laser-assisted capsulotomy before and after lens fragmentation

Studying anterior lens capsule cutting edge profiles from femtosecond laser-assisted capsulotomy procedures performed before and after lens fragmentation. Twenty eyes (10 patients) with age-related cataract underwent femtosecond laser-assisted surgery (FLACS) using the Ziemer Z8 platform. First step of laser surgery was either capsulotomy (group first) or fragmentation (group second). One eye of each patient was assigned randomly, the second eye treated with the different sequence of procedures. After anterior capsule removal, tissue was fixed in cacodylate-buffered solution and cutting-edge profiles were analysed using scanning electron microscopy (SEM). All cases had cataract grade 2 and 3 based on LOCS III grading. SEM analysis showed more smooth edges in the first group, especially in cases with pseudoexfoliation (P = 0.037); more tags and bridges and a significant number of staggered cutting patterns (7 out of 10 cases) in the second group. All cases evolved the same microgroves with “valleys and mountains “ as signs of the photodisruption process. Femtosecond laser capsulotomy should be performed before lens fragmentation minimizing the rate of cutting errors. Especially in eyes with advanced cataract, as intracapsular pressure may increase due to lens fragmentation without anterior capsular opening.

Perioperative pupil size in low-energy femtosecond laser-assisted cataract surgery

Purpose To assess potential changes in pupil size during femtosecond laser-assisted cataract surgery (FLACS) using a low-energy laser system. Methods The pupil sizes of eyes undergoing FLACS were measured using the Ziemer LDV Z8 by extracting images from the laser software after each of the following steps: application of suction, lens fragmentation, and capsulotomy. Furthermore, the pupil diameters were measured based on preoperative surgical microscope images and after releasing the suction. Paired t-test and the two one-sided tests (TOST) procedure were used for statistical analyses. The horizontal and vertical pupil diameters were compared in each of the steps with preoperative values. Results Data were available for 52 eyes (52 patients, mean age 73.4 years, range 51–87 years). The equivalence between mean preoperative pupil size and status immediately after femtosecond laser treatment was confirmed (p<0.001; 95% confidence interval [−0.0637, 0.0287] for horizontal and p<0.001; 95% CI [−0.0158, 0.0859] for vertical diameter). There was statistically significant horizontal and vertical enlargement of pupil diameters between 0.15 and 0.24 mm during the laser treatment steps as compared with preoperative values (all p values <0.001). Conclusions No progressive pupil narrowing was observed using low-energy FLACS. Although a suction-induced, slight increase in pupil area became apparent, this effect was completely reversible after removing the laser interface.

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.

Femto Laser-Assisted Cataract Surgery

Cataract is a leading cause of blindness in the world, and cataract extraction is one of the most commonly performed surgeries. Preferred surgical techniques have changed over the past decades with associated improvements in outcomes and safety. Phacoemulsification is a highly successful technique first introduced over 40 years ago. It is the current method of cataract surgery, with a very low reported rate of major complications and a frequency of overall intraoperative complications of less than 2%. Application of the femtosecond laser evolved to now assist in cataract surgery and has been termed FLACS (femtosecond laser-assisted cataract surgery) and occurs in three steps: corneal incisions (including optional limbal relaxing incisions to reduce astigmatism), anterior capsulotomy, and lens fragmentation. The remaining surgical steps still require the surgeon’s hands. The FLACS technique may have some advantages compared with conventional phacoemulsification. It remains however unclear whether FLACS is globally more efficient and safer than conventional surgery. The popularity of FLACS may also be limited by its higher cost compared with conventional surgery. The potential advantages of laser-assisted surgery are yet to be determined as FLACS technology is relatively new and in continuous evolution. This chapter reports scientific data as well as our own experience with this new technology. All the platforms currently available are described.

Femtosecond laser-assisted cataract surgery for the white cataract

Aim To report the capsulotomy and lens fragmentation outcomes of white cataracts managed with the femtosecond laser (FL).Methods Outcomes of a prospective, observational consecutive case series of white cataracts (June 2012–November 2016) that underwent FL-assisted cataract surgery (FLACS) (Victus, Bausch+Lomb, Munich, Germany) at the Singapore National Eye Centre were audited. Data collected: patient demographics, type of white cataract, levelness of docking, anterior capsule position following laser, completeness of capsulotomy and fragmentation, best-corrected visual acuity (BCVA) at 1 month, intraoperative complications. Outcome measures: capsulotomy integrity, fragmentation capability and BCVA at 1 month.Results 58 eyes of 54 patients underwent FLACS. White cataract types included dry white (24 eyes), intumescent (28 eyes) and Morgagnian (6 eyes). Docking was level in 22 eyes (38.6%). Following FL, the anterior capsule level dropped in 20 eyes (34.5%). Incomplete capsulotomies occurred in 10 eyes (17.2%). Lens fragmentation attempted in 38 eyes was effective or partially effective in 31 eyes (81.6%). No anterior or posterior capsule tears occurred. LogMAR BCVA at 1 month was 0.073 (SD 0.09). Risk factors for incomplete capsulotomy were Morgagnian cataract and lens thickness (multiple logistic regression, p<0.01 and p=0.03, respectively).ConclusionThe main complication of FLACS in white cataracts was incomplete capsulotomy (17.2%), significantly associated with Morgagnian cataracts and increased lens thickness. Lens fragmentation was effected in four-fifths of white cataracts but should be avoided in Morgagnian cataracts due to possible overlap of the lens fragmentation plan and the anterior capsule.