Femtosecond Laser Capsulotomy Research Articles

Hydrodissection and femtosecond laser assisted surgery in posterior polar cataract

PurposeTo present our clinical experience using femtosecond laser-assisted cataract surgery (FLACS) and cortical cleavage hydrodissection in eyes with posterior polar cataract.MethodsMedical records of consecutive10 eyes of 6 patients with clinical diagnosis of posterior polar cataract (PPC), were retrospectively reviewed. All surgeries were done by using femtosecond laser-assisted cataract surgery. In all cases careful hydrodissection was done to separate the lens material from the posterior capsule.ResultsThere were 3 males and 3 females, ages 39–73 years (average 52.5 years), two of them were implanted with toric lenses. In all eyes hydrodissection was successfully performed and the lens material was separated from the lens capsule. The posterior capsule remained intact during nucleus removal in all cases. In one eye the posterior capsule broke during cortical cleaning and the tear was converted to posterior capsulorhexis (PCCC). No postoperative complications were recorded during follow-up in all eyes.ConclusionsHydrodissection can be safely performed in combination (but not exclusively) with FLACS, in eyes with posterior polar cataract with no evidence of a preexisting posterior capsule rent. Hydrodissection is regarded by most surgeons as contraindicated in these eyes however apparently it is more gentile to the capsule than any other surgical maneuver and allows clean and efficient separation of the lens material from the thinned posterior capsule. Femtosecond laser capsulotomy and lens fragmentation is effective and may further assist surgery by pneumo-separation of the lens material. Anterior chamber maintainer may further aid to the stability of the chamber and safety of surgery.

Mechanical protective effect of lens anterior capsule disc on corneal endothelial cells during femtosecond laser-assisted cataract surgery in a rabbit model

PurposeTo evaluate the effects of a novel technique using an isolated lens anterior capsule disc (LACD) to protect corneal endothelial cells in rabbit eyes during femtosecond laser-assisted cataract surgery.MethodsExperimental study. 40 rabbits were divided into endothelium-protected (experimental) and control groups, with 20 rabbits in each group. In the experimental group, after femtosecond laser capsulotomy, the isolated capsule disc was lifted to the corneal endothelium by an ophthalmic viscosurgical device. The endothelium was damaged for 1 min with an ultrasonic probe. The control group underwent the same surgery, except that the disc was removed immediately after capsulorhexis. Corneal endothelioscopy was performed preoperatively and on postoperative days (PODs) 3 and 7 to observe endothelial cell counts (ECC) and endothelial cell loss rate. Central corneal thickness (CCT) was measured before and at PODs 1, 3 and 7.ResultsThere were 3.59%±1.88% (p < 0.001) and 2.92%±2.14% (p < 0.001) loss of ECC in experimental group at POD3 and POD7, respectively, while those in the control group were 11.62%±7.43% and 10.34%±5.77%, respectively. On POD 1, the difference in central corneal thickness was significant(P = 0.019) between the two groups. At POD 3 and POD 7, CCT was not significantly different (P = 0.597;0.913) between the two groups.ConclusionsThe isolated LACD technique significantly reduced damage to the endothelium caused by ultrasonic energy and protects corneal endothelial cells during phacoemulsification.

Femtosecond Laser Capsulotomy in Previous Radial Keratotomy.

The aim of this study was to describe clinical experience using femtosecond laser-assisted anterior capsulotomy in eyes with previous radial keratotomy. Eyes of patients with previous radial keratotomy and cataract-related vision impairment who underwent phacoemulsification and intraocular lens implantation were retrospectively reviewed. Eyes with any vision impairment cause other than cataract or previous radial keratotomy were excluded. Sixteen postradial keratotomy eyes were included. In 5 patients, manual anterior capsulectomy was successfully performed. Six eyes underwent femtosecond laser capsulotomy using routine parameters (incision depth 500 μm and 4 μJ power), of which in 3 eyes capsulotomies were complete, whereas in the other 3 eyes incomplete capsulotomy was evident. In 3 patients, both incision depth and power parameters were doubled (incision depth 1000 μm and 8 μJ power), whereas in 2 patients, only the pulse energy was doubled (8 μJ power) and in all 6 cases, the capsulotomy was successfully completed. At the last follow-up, all capsulotomies were intact without radial tears, and the intraocular lenses were stable and central. Radial corneal scars after previous radial keratotomy may interfere with femtosecond laser-assisted anterior capsulotomy using routine parameters. Surgeons should be alert and ready to convert to manual anterior capsulectomy. Modification of the laser parameters may overcome this potential complication.

Adjusted femtosecond laser capsulotomy distance in white cataracts to decrease incomplete capsulotomy: a randomized comparative cohort study.

To compare safety and effectiveness between standard position and adjusted distance pre- and post-anterior capsule of femtosecond laser capsulotomy in white cataracts surgery. Selected white cataracts that underwent LenSx femtosecond laser capsulotomy were randomized into groups A (standard position, with 300µm symmetrically pre- and post-anterior capsule), B (increased distance with 400µm symmetrically pre- and post-anterior capsule), and C (unsymmetrical distances of 200µm pre- and 400µm post-anterior capsule, respectively). All these surgeries were performed by the same experienced surgeon. Complications, including incomplete capsulotomy and capsule tears, were recorded. In addition, femtosecond capsulotomy and phacoemulsification parameters, IOLs centrality and corrected distance visual acuity were assessed. A total of 113 eyes were included in this study. There were 8 (21.6%) incomplete capsulotomy and 1 anterior capsule tear in group A. Meanwhile, only 2 eyes (5.1%) had incomplete capsulotomy with none showing capsule tear in group B. In group C, only 1 eye (2.7%) had incomplete capsulotomy and no capsule tear occurred. Mean femtosecond laser capsulotomy time was longer in group B compared with groups A and C. Average cumulative dispersed energy, IOL centrality and corrected distance visual acuity were similar in all groups. Appropriate adjustment on femtosecond laser capsulotomy distance by reducing pre-anterior capsule and increasing post-anterior distance, may decrease incomplete capsulotomy and be more effective in white cataracts surgery. Clinical trial registration number: ChiCTR2100043863.

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.

Parameters of Capsulorrhexis and Intraocular Lens Decentration After Femtosecond and Manual Capsulotomies in High Myopic Patients With Cataracts.

Purpose: To compare the parameters of capsulorrhexis and intraocular lens decentration after femtosecond laser capsulotomy and manual continuous curvilinear capsulorrhexis in high myopic patients with cataracts.Methods: This is a prospective consecutive non-randomized comparative cohort study. Selected patients with axial length > 26.0 mm were divided into femtosecond laser capsulotomy (FS) group and manual continuous curvilinear capsulorrhexis (CCC) group. Five experienced phacoemulsification surgeons conducted all surgeries. Intraoperative complications and post-operative anterior segment photography were recorded. Intraocular lens decentration, area of capsulorrhexis, circularity, and capsule overlap were measured at 1 week, 1 month, and 2 years after surgery. Between group differences of parameters were determined with independent-sample t-test or the Mann–Whitney U-test, analysis of variance test, Pearson chi-square test, and Spearman rank correlation test.Results: The study included 142 eyes (108 patients), 68 eyes in the FS group, and 74 eyes in the CCC group. At 1 week, 1 month, and 2 years after surgery, the area of capsulorrhexis in the CCC group was significantly larger than in the FS group (P < 0.05), while no significant difference was noted in circularity values. The complete overlap ratio in the FS group was significantly higher than that in the CCC group (P < 0.05) at each measured timepoint. Significant correlations were noted between the anterior chamber depth and the area of capsulorrhexis in the CCC group (R = 0.25, P = 0.04), but did not correlate in the FS group (P > 0.05). In patients with an anterior chamber depth >3 mm, the capsule-intraocular lens (IOL) overlap of the CCC group was less than that of the FS group at all measured timepoints after surgery (P < 0.05). Meanwhile, the IOL decentration in the CCC group was significantly greater than that of the FS group in those patients at 2 years after surgery (P < 0.05).Conclusion: In high myopic patients with cataracts, with anterior chamber depth more than 3 mm, femtosecond laser capsulotomy can achieve better capsulorrhexis sizing and centering. Due to more precise capsulotomy and a better capsule-IOL overlap in the FS group, femtosecond laser capsulotomy resulted in better long-term centration of the IOL.

Stability and Visual Outcomes of the Capsulotomy-Fixated FEMTIS-IOL After Automated Femtosecond Laser–Assisted Anterior Capsulotomy

To evaluate stability and performance of a new monofocal anterior capsulotomy-fixated intraocular lens (IOL) (FEMTIS; Teleon Surgical B.V., Spankeren, Netherlands) after femtosecond laser-assisted cataract surgery (FLACS). Prospective, multicenter, interventional, noncomparative case series. FLACS with FEMTIS IOL was performed in 336 eyes of 183 cataract patients with fixation of the IOL to the anterior capsulotomy followed up for 12months. Examination included uncorrected distance visual acuity (UDVA), best-corrected visual acuity (CDVA), subjective refraction, IOL centration, posterior capsule opacification (PCO), and investigators' satisfaction questionnaire. At 12months, mean IOL rotation was 1.50 ± 1.76 degrees and decentration 0.14 ± 0.14mm from baseline (day of surgery). Mean horizontal IOL tilt was 0.70 ± 0.60 degrees and vertical 1.15 ± 1.06 degrees relative to the baseline (crystalline lens). Mean distance between IOL and iris was 0.32mm to 0.36mm for all measured meridians. Mean UDVA was 0.12 ± 0.14 logMAR (range -0.20 to 0.54 logMAR), mean CDVA -0.01 ± 0.09 logMAR (range -0.30 to 0.20 logMAR). Mean spherical equivalent was 0.35 ± 0.53 diopter (D) and 98% of eyes (n= 235) were within ±1.0 D. Median PCO score was 1 with an Nd:YAG laser rate of 3.1% after 12months. Most surgeons were very satisfied (median score: 1) with surgery and implanted IOL. Implantation of FEMTIS IOL provided excellent visual and stable refractive outcomes. IOL decentration was very low compared to other published studies and showed an exceptional high in-the-bag stability over a 12-month period. This lens benefits from femtosecond laser capsulotomies. It can be positioned very predictably and offers an optimal platform for toric and multifocal IOL optics.

Commentary: Anterior capsule polishing: The present perspective.

Commentary: Anterior capsule polishing: The present perspective.

Femtosecond laser–assisted capsulotomy with capsular marks for toric IOL alignment: Comparison of tensile strength with standard femtosecond laser capsulotomy

To compare the capsulotomy rim strength with capsular marks (CMs) to the rim strength without CMs in porcine eyes, and to demonstrate the practicality of CMs for intraoperative toric intraocular lens (IOL) alignment. LENSAR facility, Orlando, Florida, USA. Laboratory study. The biomechanical strength of the capsulotomy with CMs was tested under two different load orientations (orthogonal to or in-line with CMs). Thirty-six porcine eyes were randomly assigned to three treatment cohorts: (1) standard capsulotomy with no CMs, (2) capsulotomy with CMs for in-line tensile testing and (3) capsulotomy with CMs for orthogonal tensile testing. Study parameters were capsulotomy break force and maximum extensibility. The ease of using CMs for toric IOL alignment was also evaluated. There was no significant difference between the mean break force for standard capsulotomy (180.57mN±22 [SD]), capsulotomy with CMs with orthogonal load (178.04±20mN, P=1.000), and with in-line load (181.05±15mN, P=1.000). Likewise, the mean extensibility at the break point for standard capsulotomy (6.47±0.33mm) was equivalent to the mean extensibility with CMs with orthogonal load (6.49±0.45mm, P=1.000) and with in-line load (6.3±0.47mm, P=.960). In the implanted eyes, toric IOLs were found to be easily aligned with the CMs. The femtosecond laser capsulotomies with CMs were equivalent in tensile strength and extensibility to standard femtosecond laser capsulotomies and showed high potential for effective alignment of toric IOLs.

The Clinical Relationship of Anterior Capsular Tears and Vertical Spacing in the Femtosecond Laser Capsulotomy Procedure.

To evaluate the frequency of anterior capsule tears and capsule edge irregularities in femtosecond laser anterior capsulotomy, including the effect of optimized vertical spacing settings. Three thousand eight hundred thirty-four cases were examined and grouped according to the femtosecond laser capsulotomy settings using manufacturer default settings with a vertical spacing of 10, 15, and 20 µm. Capsulotomy edge irregularities and anterior capsule tears were recorded intraoperatively. The anterior capsule tear rates for the 10, 15, and 20 µm groups were 0.79%, 0.35%, and 0.09%, respectively. The capsule edge irregularity rates for the 10, 15, and 20 µm groups were 6.25%, 1.13%, and 1.15%, respectively. The treatment times for the 10, 15, and 20 µm groups were 1.6, 0.7, and 0.8 second, respectively. The risk reduction of anterior capsule tears positively correlated with the 15 and 20 µm group settings. The anterior capsule tear rate difference between the 10 and 20 µm group settings was statistically significant. Capsule edge irregularity rates were reduced in the 15 and 20 µm group settings. Eye movement was monitored in the 20 µm group and was observed in 9 of 13 patients with capsule edge irregularities. Anterior capsule tear rates are low with femtosecond laser cataract surgery. The rate can be further reduced with optimization of the settings, including an increase in vertical spacing. [J Refract Surg. 2019;35(5):280-284.].

Advances in capsulorhexis.

Continuous curvilinear manual capsulorhexis is currently the standard of cataract surgery. In the past several years, new technologies have been developed to improve the consistency and safety of capsulorhexis creation. This article reviews the most recent technologies in capsulotomy formation and their advantages and disadvantages. Guidance devices, femtosecond laser capsulotomy and precision pulse capsulotomy improve the centration, circularity and precision of anterior capsulorhexis and capsulotomy. These developments show particular promise for complex cataract surgeries, though clinical data on the refractive outcomes and complication rates of these technologies are currently limited and warrant additional investigation. New technological advances in capsulorhexis help surgeons achieve a more ideal capsulotomy geometry. Whether this translates into more predictable refractive outcomes and safer surgeries remains an area of future study.

Intereye comparison of femtosecond laser–assisted cataract surgery capsulotomy and manual capsulorhexis edge strength

To compare the breaking force required to tear the explanted capsule after femtosecond laser-assisted cataract surgery in the worse eye and manual cataract surgery in the contralateral eye. Personaleyes, Sydney, Australia. Prospective nonrandomized case study. Patients with bilateral cataract had femtosecond laser-assisted cataract surgery with the Lensx laser in the eye with worse vision and manual cataract surgery in the contralateral eye. Each explanted capsule was stretched mechanically, and the breaking force and strain in grams (g) were compared. When a large contralateral difference in capsule strength was found, scanning electron microscopy (SEM) was applied to determine whether morphologic imperfections were present in a case with a weak capsule. Paired samples of 78 eyes of 39 patients were tested. The mean breaking force was not significantly different between manual capsulorhexes (2.3g±2.0 [SD]) and femtosecond laser capsulotomies (2.0±2.2g, P=.52). The breaking strain for the manual samples (33.8%±18.3%) and for the femtosecond laser samples (34.6%±18.6%) were also not significantly different (P=.81). In 5 patients, in the femtosecond group, the capsules required considerably less force to break than the capsules in the manual group. However, the SEM images of these samples did not show specific laser imperfections. In paired human eyes, the capsulotomies created by a femtosecond laser with a contact lens interface were as strong as manual capsulorhexes.

Comparison of Maximum Stretch Forces between Femtosecond Laser-Assisted Capsulotomy and Continuous Curvilinear Capsulorhexis.

The current study reports comparing the postoperative mechanical properties of the anterior capsule between femtosecond laser capsulotomy (FLC) and continuous curvilinear capsulorhexis (CCC) of variable size and shape in porcine eyes. All CCCs were created using capsule forceps. Irregular or eccentric CCCs were also created to simulate real cataract surgery. For FLC, capsulotomies 5.3 mm in diameter were created using the LenSx® (Alcon) platform. Fresh porcine eyes were used in all experiments. The edges of the capsule openings were pulled at a constant speed using two L-shaped jigs. Stretch force and distance were recorded over time, and the maximum values in this regard were defined as those that were recorded when the capsule broke. There was no difference in maximum stretch force between CCC and FLC. There were no differences in circularity between FLC and same-sized CCC. However, same-sized CCC did show significantly higher maximum stretch forces than FLC. Teardrop-shaped CCC showed lower maximum stretch forces than same-sized CCC and FLC. Heart-shaped CCC showed lower maximum stretch forces than same-sized CCC. Conclusively, while capsule edge strength after CCC varied depending on size or irregularities, FLC had the advantage of stable maximum stretch forces.

Zepto precision pulse capsulotomy: A new automated and disposable capsulotomy technology.

Despite the appeal of an automated method of creating a perfectly circular anterior capsulotomy, global adoption of femtosecond laser capsulotomy (FSLC) has been limited by its high acquisition and per case cost. In addition, the femtosecond laser's large size and the need for eye docking create surgical efficiency and workflow challenges. The Zepto precision pulse capsulotomy (PPC) technology creates a circular anterior capsulotomy of a precise diameter using a disposable handpiece and tip that are used in the normal surgical sequence. Extensive preclinical and clinical testing has resulted in the US Food and Drug Administration (FDA) approval of the technology. Zepto PPC holds promise for complicated eyes such as those with intumescent or brunescent lenses, zonulopathy, or small pupils. This paper and the accompanying videos describe and demonstrate the technique and review the published studies.

Superior Rim Stability of the Lens Capsule Following Manual Over Femtosecond Laser Capsulotomy.

Cataract surgery requires the removal of a circular segment of the anterior lens capsule (LC) by manual or femtosecond laser (FL) capsulotomy. Tears in the remaining anterior LC may compromise surgical outcome. We investigated whether biophysical differences in the rim properties of the LC remaining in the patient after manual or FL capsulotomy (FLC) lead to different risks with regard to anterior tear formation. Lens capsule samples obtained by either continuous curvilinear capsulorhexis (CCC) or FLC were investigated by light microscopy, laser scanning confocal microscopy, and scanning electron microscopy; atomic force microscopy (AFM) was used to test the biomechanical properties of the LC. The mechanical stability of the LC following either of the two capsulotomy techniques was simulated by using finite-element modeling. Continuous curvilinear capsulorhexis produced wedge-shaped, uniform rims, while FLC resulted in nearly perpendicular, frayed rims with numerous notches. The LC is composed of two sublayers: a stiff epithelial layer that is abundant with laminin and a softer anterior chamber layer that is predominantly made from collagen IV. Computer models show that stress is uniformly distributed over the entire rim after CCC, while focal high stress concentrations are observed in the frayed profiles of LC after FLC, making the latter procedure more prone to anterior tear formation. Finite-element modeling based on three-dimensional AFM maps indicated that CCC leads to a capsulotomy rim with higher stress resistance, leading to a lower propensity for anterior radial tears than FLC.

Femtosecond laser capsulotomy versus manual capsulotomy: a Meta-analysis.

To perform a Meta-analysis on the precision and safety of femtosecond laser (FSL) capsulotomy compared with manual continuous curvilinear capsulotomy (CCC). We searched PubMed, EMBASE, Web of Science, the Cochrane Library databases, and Clinical Trials.gov that maintained our inclusion criteria. Reference lists of retrieved articles were also reviewed. The effects of morphology of capsulorhexis and the tears of anterior capsule were calculated by using random-effect models. We identified 4 randomized and 7 nonrandomized studies involving 2941 eyes. The diameter of capsulotomy and the rates of anterior capsule tear showed no statistically difference between FSL group and manual group (MD=0.03; 95%CI, -0.03 to 0.09, P=0.31), and (OR=1.40; 95%CI, 0.28 to 6.97, P=0.68) respectively. In terms of the circularity of capsulotomy, FSL group had a more significant advantage than the manual CCC group (MD=0.09; 95%CI, 0.05 to 0.12, P<0.0001). Our Meta-analysis shows that FSL can perform a capsulotomy with more precision and higher reliability than manual CCC. The results in diameter of capsulotomy and the rate of anterior capsule tears was no significant difference between FSL and manual CCC groups. However in terms of circularity, the FSL was superior to the manual procedure.

Comparison of Manual, Femtosecond Laser, and Precision Pulse Capsulotomy Edge Tear Strength in Paired Human Cadaver Eyes

To compare the anterior lens capsulotomy edge tear strength created by manual continuous curvilinear capsulorhexis (CCC), femtosecond laser capsulotomy (FSLC), and a new automated precision pulse capsulotomy (PPC) device. A 3-arm study in paired human cadaver eyes. A total of 44 eye specimens from 22 donors in the United States. Capsulotomy was performed in all eye specimens using manual CCC, a femtosecond laser (LenSx, Alcon, Fort Worth, TX), or an automated PPC device (Zepto, Mynosys Inc., Fremont, CA). The first study arm consisted of 8 pairs of eyes in which 1 eye received PPC and the fellow eye received FSLC. The second study arm consisted of 8 pairs of eyes, with 1 eye receiving PPC and the fellow eye receiving manual CCC. The third study arm consisted of 6 pairs of eyes, with 1 eye receiving a manual CCC and the fellow eye receiving FSLC. After phacoemulsification, 2 capsulotomy edge retractors attached to force transducers were used to stretch the capsulotomy edge of each eye and to measure the resisting force until the capsulotomy edge was torn. Capsulotomy edge tear strength in millinewtons. The PPC edge tear strength was greater than that of FSLC for all 8 pairs of eyes by an average factor of 3.1-fold (PPC mean 73.3±24.9 mN vs. femtosecond laser mean 26.1±6.8 mN; P= 0.012, Wilcoxon matched-pairs, signed-ranks test). The PPC tear strength was greater than that of manual CCC for all 8 pairs of eyes by an average factor of 4.1-fold (PPC mean 95±35.2 mN vs. manual CCC mean 29.1±23.1 mN; P= 0.012, Wilcoxon matched-pairs signed-ranks test). There was no significant difference in the tear strength of capsulotomies produced by manual CCC (mean 21.3±4.9 mN) and FSLC (mean 24.5±11.4 mN) (P= 0.75, Wilcoxon matched-pairs signed-ranks test). The strength of the PPC capsulotomy edge was significantly stronger than that produced by femtosecond laser or manual CCC.

Light and scanning electron microscopy of anterior lens capsule following different capsulorhexis techniques

Aim - to assess the morphology of anterior lens capsules following circular capsulorhexis, for which capsulotomy was either manual or femtosecond (FS) laser produced. A total of 30 capsular samples obtained during phacoemulsification surgery were studied by light and scanning electron microscopy. All the samples were divided into 3 groups of 10 according to the type of capsulotomy: group 1 - manual, groups 2 and 3 - FS laser produced (with the laser set at high or low energy level, respectively). In manual capsulorhexis, capsular disk edges were rather smooth all the way round. Rare notches and dents as well as fine burrs up to 4 µm long could only be seen under high magnification. In FS laser capsulotomy groups, under low magnification already, capsular disk edges appeared stepped, stratified, and notched (some notches were up to 20 µm deep). The said changes were more significant following low-energy laser treatment, while high-energy levels were notable for 'melted' disk edges. Regardless of the technique used, all the disks carried a zone of de-epithelization of different width along the free edge. The differences revealed may result from several factors: 1) less accurate focusing of the laser due to fine torsional eye movements and minimal shape changes of the applanated cornea; 2) peculiarities of FS laser-tissue interaction, particularly, cavitation bubbles that are formed during tissue evaporation and tend to merge, subsequently producing the incision and demarcation line. Moreover, photothermal effects of laser radiation on epithelial cells within the anterior lens capsule cannot be excluded.

Optical coherence tomography and 3-dimensional confocal structured imaging system–guided femtosecond laser capsulotomy versus manual continuous curvilinear capsulorhexis

To compare the features of capsulotomy obtained during femtosecond laser-assisted cataract surgery with those of continuous curvilinear capsulorhexis (CCC) obtained using a standard manual technique. Ophthalmology Clinic, Department of Medicine and Science of Ageing, University G. D'Annunzio Chieti-Pescara, Chieti, Italy. Prospective randomized clinical study. Candidates for cataract extraction were randomized into 1 of 3 groups as follows: Lensx femtosecond laser-assisted cataract surgery capsulotomy (laser group 1), Lensar femtosecond laser-assisted cataract surgery capsulotomy (laser group 2), and manual CCC (manual group). Each group comprised 30 eyes (30 patients). The capsulotomies in laser group 1 and laser group 2 showed significantly better circularity than the manual CCCs at 7 days (P<.001). There was a significant correlation between the intended versus achieved capsulotomy size in the 2 laser groups. Both laser groups had better intraocular lens (IOL) centration than the manual group at all timepoints (P<.001). Between-group differences in uncorrected and corrected distance visual acuities were not statistically significant. The residual spherical equivalent and mean absolute error were statistically significantly smaller in the 2 laser groups than in the manual group (P=.038) and increased significantly over time in all the groups (P<.001). Femtosecond laser capsulotomies showed better circularity with more predictable size than manual CCCs. In addition, IOL centration was better immediately after surgery and over time with better refractive results in the 2 laser groups.

Morphological changes in the edge structures following femtosecond laser capsulotomy with varied patient interfaces and different energy settings

To ascertain the morphological changes in the edge structure of femtosecond laser-derived capsulotomy specimens using varying patient interfaces and different laser pulse energies. In this experimental clinical study femtosecond laser-assisted capsulotomies were performed in 30 eyes using the LenSx femtosecond laser (LenSx, Alcon, Fort Worth, TX, USA). Surgery was performed using either a rigid curved contact interface (group 1, 15 eyes) or a curved interface with a soft contact lens between cornea and interface (group 2, 15 eyes). The laser pulse-energy was set to 15μJ in group 1 and to 5μJ in group 2. After the removal of the anterior capsule, half of the specimens from each group underwent either further staining for light microscopy (LM) or scanning electron microscopy (SEM). Cell configuration, capsule shape, and edge abnormalities were analysed on a morphological basis. LM showed continuous anterior capsular incisions with a prominent demarcation line along the cutting edge, as well as tags and bridges, which were more pronounced in group 1. SEM revealed further smaller microgrooves and sawtooth patterns in both groups, and a more regular demarcation line configuration in group 2. A soft contact lens interface with a subsequent laser pulse energy of 5μJ resulted in fewer tags and bridges, smoother edges, and a more regular and thinner demarcation line on specimens edges of femtosecond laser-performed capsulotomies compared to a rigid curved 15μJ interface application.