Femtosecond Laser-assisted Surgery Research Articles

Effectiveness of femtosecond laser-assisted cataract surgery in patients over 50 years of age in a private ophthalmology clinic in the city of Rosario, year 2022

Introduction: Cataract surgery is the most effective treatment to restore vision in those patients whose vision is significantly affected by lens opacity. This procedure has proven to be safe and effective, which has led to a significant improvement in the quality of life of patients who undergo this surgical intervention.Objective: To determine the effectiveness of such femtosecond laser-assisted surgery in patients over 50 years of age seen at the private ophthalmology clinic in the year 2022.Materials and methods: Quantitative observational study, with a descriptive, cross-sectional and retrospective design, carried out in a private ophthalmology clinic, during the period between May and June 2023. The population consisted of patients over 50 years of age, regardless of sex. The sample was non-probabilistic by convenience. Data collection was carried out through the review of the patients' medical records, obtained from the clinic's database. The data collected were entered into an Excel spreadsheet for subsequent analysis with Jamovi statistical software. Qualitative variables were expressed using frequency tables and pie charts or bar graphs, as appropriate. The Student's t test was used to compare quantitative variables with symmetrical or Gaussian distribution. Histograms and box plots were used to represent the distribution of quantitative variables.Results: Twenty-six patients were evaluated, their mean age was 69 years. Fifty percent of the operated eyes presented visual acuity less than or equal to 0.4 before surgery, while after surgery 50% of the operated eyes showed visual acuity above 0.9. It was observed that post-surgery 84.6% of the operated eyes increased visual acuity by up to 6 tenths and 15.4% increased visual acuity by at least 7 tenths. Twenty-five percent of the operated eyes decreased the number of endothelial cells post surgery by up to 2.33%, while there were 10% of operated eyes that showed no reduction of endothelial cells post surgery. No complications were identified in any of the femtosecond laser-assisted surgeries performed.Conclusions: It could be inferred that this femtosecond laser-assisted cataract surgery is effective, reproducible and safe

Метод лечения рецидивирующего герпетического кератита на основе послойной кератопластики с фемтосекундным сопровождением (серия клинических случаев)

Purpose. To evaluate the clinical efficacy of lamellar keratoplasty in the treatment of recurrent herpetic keratitis with femtosecond laser-assisted corneal surgery. Material and methods. In two clinical cases, lamellar keratoplasty with femtosecond laser-assisted corneal surgery was performed. Preoperative and postoperative visual acuity, refractometry, keratotopography, pachymetry were examined. Conducted courses of conservative treatment: antiviral, anti-inflammatory, desensitization therapy using vaccination «Vitogerpavak». Results. Evidence of the effectiveness of the proposed method was obtained - stabilization and relief of the inflammatory process, increased visual acuity and cosmetic effect. Conclusion. Cases of successful treatment of recurrent herpetic keratitis after intensive courses of conservative treatment followed by lamellar keratoplasty with femtosecond laser-assisted surgery are presented. The use of femtolaser technologies, which allow dosed excision of the affected tissue at a certain depth according to predetermined parameters, contributes to the achievement of high functional results. Lamellar keratoplasty with the maximum possible excision of scar tissue and its replacement with a donor cornea is a minimally invasive effective method to restore the transparency of the cornea after therapeutic treatment of recurrent herpetic keratitis. Key words: keratoplasty, herpetic keratitis, femtosecond laser

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.

Comparison of Complication Rates between Manual and Femtosecond Laser-Assisted Techniques for Intrastromal Corneal Ring Segments Implantation in Keratoconus

ABSTRACTPurpose: To compare the incidence of complications between manual and femtosecond-laser assisted surgery for intrastromal corneal ring segments (ICRS) implantation.Material and methods: This study included keratoconus patients who had ICRS implantation using manual dissection and using the femtosecond laser with a minimum follow-up of 12 months. Uncorrected (UDVA) corrected (CDVA) distance visual acuity (CDVA), refraction, corneal topography and aberrometry, pachymetry map and slit-lamp microscopy were assessed before and after surgery.Results: The study included 265 eyes in the manual group and 111 in the femtosecond laser group. In the manual group, there were complications in 48 eyes (18.11%); while in the femtosecond laser 4 eyes had a complication (3.6%). In the manual group, the most frequent complications were ICRS exchange/adjustment for visual and refractive enhancement (25 eyes; 9.43%) and late ICRS spontaneous extrusion (15 eyes; 5.66%). In the manual group, 81.25% of complications were observed during the first 3 years of surgeon’s experience. Eyes who suffered a complication had preoperatively higher mean refractive (p = .002) and topographic cylinder (p = .003) and lower UDVA (p = .005) and CDVA (p = .002). After a second surgical procedure for complication management visual, refractive and topographic outcomes significantly improved.Conclusion: Manual mechanical ICRS surgery shows a higher rate of intra- and postoperative mechanical and refractive complications when compared to femtosecond laser assisted technique. The incidence is specially higher during the surgeon’s first years of implementation of the technique.

A randomized controlled trial comparing femtosecond laser–assisted cataract surgery versus conventional phacoemulsification surgery

To compare the clinical results of conventional phacoemulsification surgery (CPS) with femtosecond laser-assisted cataract surgery. Guy's & St Thomas' NHS Foundation Trust, London, United Kingdom. Single-center prospective randomized interventional case-controlled trial. Patients undergoing cataract surgery were randomized to receive either CPS or femtosecond laser-assisted cataract surgery. The surgery was performed with a femtosecond laser (Lensx), and all operations were performed with a gravity-fluidics torsional phacoemulsification machine (Infiniti). The visual acuity, refraction, central corneal thickness (CCT), central foveal thickness (CFT), endothelial cell loss, and rates of intraoperative and postoperative events were recorded. Quality of life outcomes were measured with the EuroQOL 5 dimensions questionnaire (EQ-5D) and patient-reported quality of vision was assessed witha cataract surgery patient-reported outcome measures questionnaire (Cat-PROM5). The study comprised 400 eyes of 400 patients who had CPS (n=200) or femtosecond laser-assisted cataract surgery (n=200). Seven patients (3.5%) in the femtosecond laser-assisted group were not able to complete the treatment and received CPS. The mean uncorrected distance visual acuity (logarithm of the minimum angle of resolution [logMAR]) 0.15±0.21 (SD) and 0.15±0.19 logMAR after CPS and femtosecond laser-assisted surgery, respectively (P=1.0); the pinhole-corrected visual acuity was 0.04±0.12 and 0.04±0.12, respectively (P=1.0); the increase in CCT was 13±19μm and 15±25μm, respectively (P=.5); and the endothelial cell loss was 9.7±13.7 % and 10.2%±13.7, respectively (P=.76). The manifest refraction spherical equivalent error was -0.14±0.60 diopters (D) after CPS and -0.12±0.60 D after femtosecond laser-assisted surgery (P=.74); the mean change in CFT was 9±35μm and 6±35μm, respectively (P=.55); and the rate of posterior capsule rupture was 3% and 0%, respectively (P=.03). This study confirms the nonsignificant differences between 2 treatment modalities, notwithstanding a significant reduction in posterior capsule ruptures in the femtosecond laser-assisted surgery group.

Comparison of femtosecond laser-assisted corneal intrastromal xenotransplantation and the allotransplantation in rhesus monkeys

BackgroundIn our previous study, we showed that both allogeneic and autogeneic small-incision femtosecond laser-assisted corneal intrastromal transplantation are safe and effective surgeries. However, the results of small-incision femtosecond laser-assisted intrastromal xenotransplantation have not yet been explored. Additionally, we suggest that glycerol-dehydrated corneal lamellae might provide a possible alternative for this xenogenic implantation approach.MethodsCorneal inlay lamellae were produced from rabbits and humans using femtosecond laser-assisted surgeries and were dehydrated in glycerol for 1 week at 4 °C. These xenogeneic glycerol-dehydrated grafts and fresh allogeneic monkey lamellae were then implanted into rhesus monkeys using small-incision femtosecond laser assistance. Postoperatively, clinical examinations, AS-OCT measurements and tear inflammatory mediator assays were performed.ResultsThere were no significant changes in the transparency of the corneal lamellae after glycerol dehydration. Following implantation, no evidence of tissue rejection or severe inflammatory responses was observed in the monkeys, and the host corneas remained transparent throughout a 6-month observation period. The grafts were clearly visible via AS-OCT. Corneal thickness increased 1 week postoperatively but subsequently declined and remained unchanged 1 month after surgery. Significant changes were observed in all tear inflammatory mediators in the ‘Rabbit to Monkey’ group. The trends in changes of tear inflammatory mediators in the ‘Human to Monkey’ group were similar to those in the ‘Rabbit to Monkey’ group. At 1 month post-surgery, the levels of most tear inflammatory mediators had decreased, with the exception of IL-1β, TGF-β1 and IFN-γ in the allotransplantation group.ConclusionSmall-incision femtosecond laser-assisted intrastromal transplantation minimized invasiveness and improved surgical efficiency. In addition, the host cornea maintained a high level of biocompatibility. Glycerol-dehydrated corneal lamellae might be potentially useful as an alternative inlay xenogeneic material. In this study, we also describe a new treatment that can be used in keratoconus, corneal ectasia, presbyopia, hyperpresbyopia and other diseases.

Clinical outcomes using standard phacoemulsification and femtosecond laser-assisted surgery with toric intraocular lenses.

PurposeTo compare the 1-month and 1-year results of toric intraocular lens (IOL) implantation with standard (manual) phacoemulsification vs femtosecond laser-assisted surgery.Patients and methodsRefractive data, visual acuity data, and ocular aberration measured with a wavefront aberrometer were collected for two groups of patients from one site. The first group had standard phacoemulsification, while the second group had femtosecond laser-assisted surgery, and both groups were implanted with toric IOLs, either monofocal or multifocal. Differences in visual acuity, refractive outcomes, and higher order aberrations – total, corneal, and internal – were evaluated at 1 month and 1 year postoperatively.ResultsToric IOLs were implanted in 62 eyes using standard phacoemulsification and 53 eyes using femtosecond laser-assisted surgery. Uncorrected visual acuity and best-spectacle-corrected visual acuity at 1 month and 1 year were not statistically significantly different between the groups (P>0.05) nor was the mean cylinder or mean spherical equivalent refraction (P>0.12). Total ocular higher order aberrations were significantly different between the groups (P<0.05), but absolute differences appeared to be the same. Internal vertical coma was significantly lower in the femto group at 1 year (P=0.03). Differences in aberrations did not correlate with corrected or uncorrected visual acuity.ConclusionPatients who underwent uncomplicated lens surgery with toric IOLs in both the groups had comparable refractive outcomes in terms of visual acuity and residual refraction at 1 year. The femto group had significantly lower internal vertical coma at 1 year.

Cirugía de catarata con láser de femtosegundo en glaucoma

ObjectiveTo evaluate the efficacy and safety of femtosecond laser-assisted cataract surgery in patients with glaucoma. MethodsA retrospective study was conducted on patients with glaucoma underwent cataract surgery by means of a femtosecond laser-assisted surgery. The study included consecutive glaucoma patients undergoing femtosecond Laser-assisted cataract surgery between January 2012 and December 2013 by one experienced surgeon. Data were collected about patient demographics, preoperative investigations, postoperative data, and postoperative complications. Visual acuity was assessed with the logarithm of the minimum angle resolution [logMAR]) test. Results24 subjects, 6 (25%) men and 18 (75%) women, were included in the study. Mean (Standard deviation) visual acuity significantly improve from 1.3 (0.78) to 0.55 (0.59), P=0.010. The most frequently observed adverse event was subconjuctival hemorrhage in 7 (29%) patients. One patient had a posterior capsular rupture that required vitrectomy. ConclusionThe results of our study suggest that femtosecond laser-assisted cataract surgery may be an effective and safe option in glaucoma patients. Appropriate patient selection is essential to the outcome of the technique.

Impact of Crystalline Lens Opacification on Effective Phacoemulsification Time in Femtosecond Laser-Assisted Cataract Surgery

To compare effective phacoemulsification time in cataract surgery performed by manual phacoemulsification vs femtosecond laser-assisted lens fragmentation. Retrospective, consecutive, nonrandomized, comparative case series. The setting was the Department of Ophthalmology, Goethe-University, Frankfurt, Germany. The study population included 150 eyes of 86 patients with senile cataract. In the intervention, 88 eyes (group 1) underwent femtosecond laser-assisted surgery (corneal incisions, capsulotomy, lens fragmentation) using the LenSx platform (Alcon) and residual lens work-up with pulsed ultrasound energy (Infiniti Vision System; Alcon). In 62 eyes (group 2), complete cataract removal was performed with phacoemulsification only, using pulsed ultrasound energy with the same device (Infiniti). Nucleus staging (Pentacam nucleus staging; PNS) was evaluated using Pentacam HR (Oculus); endothelial cell density was measured using specular microscopy (NonCon Robo). The main outcome measures were as follows. Mean preoperative PNS staging was assessed using an automatic ordinal scaling (PNS-O, grades 0-5) and a manually defined density grid derived from Scheimpflug imaging (PNS-P [%]). Effective phacoemulsification time and endothelial cell loss were evaluated in both groups. Preoperative PNS-O and PNS-P showed no significant difference between groups (P = 0.267). Overall mean effective phacoemulsification time was significantly lower in group 1 (1.58 ± 1.02 seconds) compared to 4.17 ± 2.06 seconds in group 2 (P = 0.001). Effective phacoemulsification time was significantly lower in group 1 for all PNS-O stages (P < 0.001). With increasing preoperative PNS-P, effective phacoemulsification time increased in both groups; however, this gain was noticeably, but not significantly, lower in group 2. Endothelial cell loss was significantly lower in group 1 (P = 0.02). Femtosecond laser-assisted cataract surgery allows a significant reduction in effective phacoemulsification time, which correlates positively with the preoperative lens opacity.

Allopatric femtosecond laser gas-bubble formation in a closed system

To test a possible mechanism for allopatric gas-bubble formation in femtosecond laser-assisted surgery using an experimental closed system. Bascom Palmer Eye Institute, University of Miami, Miami, Florida, USA. Plastic bottles were filled with balanced salt solution (BSS). Femtosecond laser (IntraLase) flap-mode cuts were made on the walls of the BSS bottles. After femtosecond laser application, the BSS bottles were viewed under the excimer laser microscope and the results photographed. Next, the BSS bottles and laser cuts were imaged with optical coherence tomography. In-bottle gas bubbles were consistently produced in the closed system. No cut lines crossed the inner wall of the BSS bottles. Results show that in situ gas-bubble formation as a mechanism for gas-bubble formation is a possible alternative to gas traveling through the anterior segment and into the intraflap laser space.