A Review of Laser-Assisted Versus Traditional Phacoemulsification Cataract Surgery

Femtosecond laser-assisted cataract surgery versus conventional phacoemulsification: A meta-analysis of randomized controlled trials

PURPOSE

The main purpose of our study is to compare the adverse events occurrence, complications, and postoperative outcomes of Femtosecond Laser-Assisted Cataract Surgery (FLACS) versus conventional phacoemulsification surgery (CPS) in adult patients undergoing cataract surgery.

METHODS

We conducted our research using PubMed, Scopus, and MEDLINE through EBSCOhost from 2012 to July 2022 with English and Spanish language restriction, including only Randomized Controlled Trials (RCTs). The PRISMA guidelines were observed for data abstraction, including a random-effects model for each outcome.

RESULTS

We analyzed 4844 eyes from 23 RCTs with some low risk of bias according to RoB 2 tool. We found statistically significant differences between the FLACS and CPS groups for the mean absolute error (MD = -0.12, 95% CI:-0.22-[-0.02], p = 0.01), the circularity of capsulorhexis (MD = 0.04, 95% CI: 0.04-0.05, p ≤ 0.00001), IOL centration (D = -0.07, 95% CI:-0.09-[-0.05], p ≤ 0.00001), CDE count (MD = -1.75, 95% CI: -2.75-[-0.74], p = 0.0006), mean phacoemulsification time (MD = -12.90, 95% CI:-20.89-[-4.92], p = 0.002), EPT (MD = -0.93, 95% CI: -1.68-[-0.019], p = 0.01) and endothelial cell density loss ((MD = -0.6, 95% CI: -1-[-0.19], p = 0.004). Also, the safety analysis showed a lower incidence of posterior capsule tear (PCT) in the FLACS group (OR =0.29, 95% CI: 0.09-1, p = 0.05).

CONCLUSIONS

Our results suggest that FLACS might be helpful for patients with relatively dense cataracts and low preoperative endothelial cell values.

Lens Fragmentation with Picosecond Laser Pulses After Artificial Cataract Induction with Microwaves

Objectives: In this work we demonstrate the first laboratory study results of lens fragmentation with low-energy picosecond ultrashort laser pulses after artificial induction of cataract with microwave radiation on an ex vivo animal model. Background: This method will be evaluated with regard to the further development of lens fragmentation with novel ultrashort picosecond laser systems instead of ultrasonic phacoemulsification or the significantly more complex femtosecond laser fragmentation. Methods: As samples we used postmortem porcine eyes. The lenses were dissected and then irradiated in a microwave oven for artificial cataract induction. Subsequent computer-driven lens fragmentation was performed with a 12 ps, 1064 nm pulsed laser source with 100 µJ pulse energy, and 10 kHz pulse repetition rate. Results: Both the artificial cataract induction and the lens fragmentation were demonstrated. When inducing cataract, different degrees/stages of opaqueness and hardness could be achieved with different irradiation times and methods. The fragmentation with 12 ps pulses led to good results with regard to ablation depth and rate, especially for the softer lenses. Conclusions: As could be shown, low-energy picosecond ultrashort laser pulses are feasible for cataractous lens fragmentation on an ex vivo animal model with artificial cataract induction. Thus, this technique may influence future cataract surgeries by possibly being an alternative or extension to state-of-the-art methods. This will be evaluated with further tests and studies.

Application of Silicone in Ophthalmology: A Review

This paper reviews the latest trends and applications of silicone in ophthalmology, especially related to intraocular lenses (IOLs). Silicone, or siloxane elastomer, as a synthetic polymer, has excellent biocompatibility, high chemical inertness, and hydrophobicity, enabling wide biomedical applications. The physicochemical properties of silicone are reviewed. A review of methods for mechanical and in vivo characterization of IOLs is presented as a prospective research area, since there are only a few available technologies, even though these properties are vital to ensure medical safety and suitability for clinical use, especially if long-term function is considered. IOLs represent permanent implants to replace the natural lens or for correcting vision, with the first commercial foldable lens made of silicone. Biological aspects of posterior capsular opacification have been reviewed, including the effects of the implanted silicone IOL. However, certain issues with silicone IOLs are still challenging and some conditions can prevent its application in all patients. The latest trends in nanotechnology solutions have been reviewed. Surface modifications of silicone IOLs are an efficient approach to further improve biocompatibility or to enable drug-eluting function. Different surface modifications, including coatings, can provide long-term treatments for various medical conditions or medical diagnoses through the incorporation of sensory functions. It is essential that IOL optical characteristics remain unchanged in case of drug incorporation and the application of nanoparticles can enable it. However, clinical trials related to these advanced technologies are still missing, thus preventing their clinical applications at this moment.

Analysis of intraocular lens decentration and tilt after femtosecond laser-assisted cataract surgery using swept-source anterior optical coherence tomography

Objective

To evaluate and compare the magnitude of intraocular lens (IOL) decentration and tilt following conventional and femtosecond laser-assisted cataract surgery (FLACS) using swept-source anterior optical coherence tomography (SS-OCT).

Methods

In this retrospective observational study, we enrolled patients who underwent conventional cataract surgery or FLACS with the implantation of hydrophobic 1-piece monofocal IOL. The magnitude of IOL decentration and tilt were measured using SS-OCT. Visual acuity, intraocular pressure, spherical equivalent, axial length, contrast sensitivity, and satisfaction questionnaire were evaluated before and one-month post-surgery. Additionally, postoperative internal cylinder measurements were obtained using a wavefront aberrometer. Correlation factors between each parameter and IOL decentration or tilt were analyzed.

Results

This study included 100 eyes from 100 patients. Mean IOL decentration and tilt were 0.21 ± 0.13 mm and 5.01 ± 1.49°, respectively. Conventional cataract surgery (versus FLACS, P = 0.001) and male sex (versus female, P = 0.047) were significantly correlated with higher postoperative decentration. Preoperative lens diameter (P < 0.001), preoperative lens tilt (P = 0.007), and preoperative intraocular pressure (P = 0.027) were correlated with higher postoperative tilt. Fifty eyes that underwent FLACS demonstrated mean postoperative decentration of 0.21 ± 0.13 mm and tilt of 4.64 ± 1.48°. Compared with the conventional surgery group, the FLACS group significantly differed in postoperative decentration (0.30 ± 0.12 mm, P < 0.001) but not in tilt (5.03 ± 1.35°, P = 0.173). Postoperative visual acuity did not significantly differ between the two groups.

Conclusion

Patients who underwent FLACS demonstrated better IOL decentration and tilt than those who underwent conventional cataract surgery one-month post-surgery. However, differences in IOL decentration and tilt did not affect postoperative visual acuity.

Update on Femtosecond Laser-Assisted Cataract Surgery: A Review

The advent of femtosecond lasers has resulted in a new standard in cataract surgery, intended to overmatch the paradigm of conventional phacoemulsification. Femtosecond laser-assisted cataract surgery (FLACS) enables a higher level of reproducibility, precision, accuracy, and customization when performing several steps of cataract (or lens) surgery. Capsulotomy, corneal incisions, lens fragmentation, and arcuate incisions are the main procedures performed using FLACS. As the demand for better refractive outcomes and spectacle independence increases, the features of FLACS are highly relevant, especially when considering the implantation of premium intraocular lenses, such as toric, enhanced depth-of-focus, or multifocal lenses. The present article reviews the state of the art of femtosecond laser-assisted cataract (lens) surgery, contemplating the advantages and limitations of the two types of femtosecond laser pulses available (high and low energy) by evaluating their reported outcomes and complications.

CAPSULaser - a new modality in the portfolio of cataract surgeons

To assess the efficiency and safety of capsulorhexis with CAPSULaser in comparison with standard capsulorhexis performed manually by emerging and established surgeons. Specialized Eye Hospital-Varna Bulgaria. Prospective, randomized, non-masked study. Patients were randomized to the M group (manual CCC), L group (laser CCC), and 2 surgeons. The manual CCC was targeted at 5.5 mm. The laser CCC was sized at 5.3 mm and measured with the same caliper device during photomicroscopy. The inclusion criteria were otherwise healthy eyes with cortical, nuclear, or subcapsular cataracts of any maturity with a biomicroscopically deep anterior chamber and preoperative pupil wider than 6.5 mm. The surgical time was measured for the entire procedure and only for capsulotomy. Sixty eyes of 60 patients, aged 65.8 ± 11 years, were prospectively recruited. Two surgeons (one with 3 years and one with 30 years of experience) performed the same types and number of procedures. The experienced surgeon was 2 times faster when performing manual capsulorhexis, but the time for CAPSULaser was almost the same. The size of the "laser" CCC was planned to be 5.3 and ended up with a minimum of 5.4 in 4 weeks; however, no lens prolapse from the CCC was observed. Utilization of the CAPSULaser in cataract surgery is easy and achievable for surgeons at any stage of their careers and provides controlled, well-centered capsulorhexis with no more adverse events than conventional surgery. The limitations are the requirement for a minimal pupil size of 6 mm, a deep anterior chamber, and a transparent cornea.

Cataract Grade and Pupil: Comparison Between Conventional Phacoemulsification and Low-Energy Femtosecond Laser Assisted Cataract Surgery

Purpose

This study presents a comparison of pupil changes according to cataract grade between low-energy femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification (CP) in the same patient.

Patients and Methods

Data from surgical records from patients submitted to cataract surgery with CP in one eye and FLACS in the other were retrospectively reviewed. The inclusion criterion was both eyes of the same patient having the same cataract grade in accordance with Lens Opacity Classification System (LOCS) III. Total pupil variation (TPV) was measured after recorded images, with intraindividual comparison between techniques, according to cataract grade (≤3 and >3), age and cumulative dissipated energy (CDE).

Results

The study included a total of 124 eyes of 62 patients (mean age 72.65 ± 7.64 years). Analysis showed a statistically significant difference in TPV between techniques in the grade ≤3 cataract group (0.08 ± 0.22 mm²; p=0.034), with less pupil narrowing with FLACS, but not in the grade >3 group (0.01 ± 0.23 mm²; p=0.849). Regarding CDE, a significant difference (p<0.001) was found between techniques in both softer and harder cataracts, with lower values for FLACS. Correlation between CDE and TPV was significant for CP (p=0.021) but not for FLACS (p=0.922). TPV was significantly lower in older patients (age >74 years) for both techniques (p<0.001).

Conclusion

There was a statistically significant difference between techniques (although of mild clinical relevance), with less reduction of pupil area with FLACS in softer cataracts (grade ≤3), as compared to CP. Higher levels of CDE are associated with more pupil narrowing in CP.

Pupil Status with Low-Energy Femtosecond Laser-Assisted Cataract Surgery versus Conventional Phacoemulsification: An Intraindividual Comparative Study

Purpose

To compare the pupil changes in low-energy femtosecond laser-assisted cataract surgery (FLACS) with conventional phacoemulsification (CP) intraindividually.

Patients and Methods

A retrospective review of registered surgical data from patients that undergone uncomplicated cataract surgery in a single centre, with randomly assigned femtosecond laser-assisted cataract surgery (FLACS) to one eye and conventional phacoemulsification (CP) to the other, was performed. The recorded pupil images were evaluated at pre and post laser treatment (after suction release) and at several surgical timepoints for both techniques (FLACS and CP). Pupil areas were calculated and compared in the same eye undergone FLACS (pre vs post laser treatment), between eyes (CP vs FLACS) in the same patient and between groups. Subgroups were built regarding age and ocular comorbidity.

Results

This study involved a total of 164 eyes of 82 patients (55 female, 27 male). No statistical differences regarding the total duration of surgery (p=0.805) between FLACS and CP. Pupil measurements between pre and post laser treatment in the FLACS group showed no statistically significant differences (p=0.107). The mean change in pupil area from the beginning until the end of surgery (total variation) was 6.59±2.08 mm² in the FLACS group and 6.67±2.13 mm² in the CP group, associated to less narrowing of pupil area with FLACS, although not statistically significant (p=0.080). Comorbidity group analysis revealed less, but not significant, pupil narrowing with the FLACS technique (p=0.071). No statistically significant differences between FLACS and CP concerning age subgroups were registered.

Conclusion

This study shows no significant pupil changes, namely myosis, after low-energy FLACS pre-treatment. Comparison between techniques showed less pupil variation in FLACS as compared to CP, more markedly in eyes with comorbidities (particularly with shallow anterior chamber), although non-statistically significant.

Effect of pre-fragmentation on efficacy and safety for phacoemulsification in femtosecond laser-assisted cataract surgery: a non-randomized clinical trial

Background

Ultrasound energy during phacoemulsification results in the endothelial cell loss of cornea. Crystallin lens fragmentation with softening before phacoemulsification can be used with femtosecond laser-assisted cataract surgery (FLACS) device.

Methods

This non-randomized clinical trial included patients who underwent cataract surgery and not had corneal opacity. Patients who were not possible to apply the interface on the ocular surface, were excluded. Each subject was allowed to decide the surgical method by himself/herself. Cataract surgery was performed with FLACS (groups I and II) or conventional surgical technique (group III). The FLACS group was further subdivided into two groups according to whether a lens softening procedure was performed (group I) or not (group II). The nuclear density of cataract was objectively classified by Pentacam nuclear staging (PNS), preoperatively. Surgical parameters including total phacoemulsification time (TPT), cumulative dissipated energy (CDE), and the balanced salt solution (BSS) volume consumed, were measured during the surgery. Postoperative visual outcomes were evaluated at three months after the surgery, and corneal endothelial cell count (ECC) loss were calculated based on ECC measured before the surgery and two months after the surgery.

Results

Eighty-nine eyes from 89 patients were enrolled. Fifty-three were treated using FLACS (groups I; quadrant pattern with softening of pre-fragmentation, n=31 and II; sextant pattern without softening of pre-fragmentation, n=22) and 36 (group III) with the conventional manual technique. The FLACS groups (groups I and II) had statistically significant lower TPT (P<0.001), CDE (P<0.001), and BSS volumes (P<0.001) used in the nucleus removal step compared to group III. Furthermore, ECC loss in groups I (4.59%±2.57%) and II (6.10%±3.30%) were also statistically lower compared to group III (13.49%±10.55%, P<0.001). From subgroup analysis with the PNS 2, group I showed lower pre-fragmentation time, lower CDE, lower BSS volume used during nucleus removal, and lower ECC loss compared to group II (all P<0.001).

Conclusions

Pre-fragmentation using FLACS may reduce intraoperative ultrasound energy and intraocular manipulations compared to conventional cataract surgery.

Intraoperative complications of cataract surgery using a low-energy femtosecond laser: Results from a real-world high-volume setting

In this study, we report data on intraoperative complications occurring after cataract surgery in a high-volume single-center setting using a low-energy, mobile femtosecond laser. We retrospectively reviewed the medical records of patients who underwent femtosecond laser-assisted cataract surgery (FLACS) in our hospital between August 2015 and December 2019. Among the sample of 1,806 eyes of 1,131 patients (903 left and 903 right eyes), the mean age was 75.8 years (range, 21-99 years). The overall intraoperative complication rate was 0.28% (n = 5), with three cases of anterior capsule tear (0.17%) and two cases of posterior capsule tear (0.11%). No further complications occurred. This study underlines the safety of low-energy femtosecond-assisted cataract surgery in a real-world setting with a very low rate of intraoperative complications.

Femtosecond Laser-assisted Cataract Surgery in Patients With Prior Glaucoma Surgery

PRCIS

Femtosecond laser-assisted cataract surgery (FLACS) is a safe procedure in glaucomatous eyes with prior glaucoma surgery, evidenced by stable intraocular pressure (IOP) and medication use, acceptable success rate, disease stability, and low complication rates at 1-year postoperative.

PURPOSE

The purpose of this study was to assess the 1-year efficacy and safety of FLACS in glaucomatous eyes with prior glaucoma surgery.

MATERIALS AND METHODS

Retrospective case series of all consecutive glaucomatous eyes with previous glaucoma surgery that underwent FLACS using the Catalys Precision Laser System with or without concomitant glaucoma surgery at a single ophthalmology center, between 2014 and 2020. Efficacy included change in IOP, glaucoma medication use, best-corrected visual acuity, and surgical success at 12 months postoperatively (POM12). Safety included structural and functional measures of disease stability and postoperative adverse events.

RESULTS

A total of 57 eyes with an average age of 62.6±8.1 years were included. At POM12, IOP decreased from 14.5±6.6 mmHg to 13.5±3.7 mm Hg (P=0.22) and glaucoma medication use decreased from 2.1±1.5 to 1.8±1.4 with a marginal significance (P=0.089). Best-corrected visual acuity improved significantly in both groups (P<0.001) and surgical success ranged between 74% and 90% according to the study's success criteria. Safety was favorable with disease stability evidenced by lack of deterioration in cup-to-disc ratio, visual field mean deviation, retinal nerve fiber layer thickness, and ganglion cell-inner plexiform layer thickness. One eye with prior history of trabeculectomy experienced transient bleb leak. Other adverse events were minor without sight-threatening sequelae.

CONCLUSIONS

The results of this study suggest that FLACS with or without concomitant glaucoma surgery could be a safe procedure in glaucomatous eyes-a population for which FLACS has been relatively contraindicated. Nonetheless, in those with preexisting filtering bleb, extra attention should be paid to the bleb area.

Ultrasound energy consumption and macular changes with manual and femtolaser-assisted high-fluidics cataract surgery: a prospective randomized comparison

PURPOSE

The purpose of the study was to compare ultrasound (US) consumption and central macular thickness (CMT) and volume changes with manual and femtosecond laser (FSL)-assisted cataract nucleus workup.

METHODS

Sixty patients scheduled for immediate sequential bilateral surgery underwent a prospective randomized intraindividual comparison of nucleus sector fragmentation performed manually in one eye and with low-energy FSL assistance in the partner eye, followed by high-fluidics phacoaspiration with a maximum US power of 30%. Ultrasound (US) energy consumption and macular thickness and volume were compared as measured by intraoperative effective phacoemulsification time (EPT) and high-resolution spectral domain optical coherence tomography pre- and 1 week, 3 weeks and 6 weeks postoperatively. Results are presented as means ± SD or medians [min; max].

RESULTS

Fifty-two patients completed the full follow-up. For the manual and FSL-assisted groups, nuclear hardness was almost identical with a mean LOCS III grade of 2.44 ± 1.08 and 2.50 ± 1.00 (p = 0.371). Median EPT was 1.40 [0.2; 8.3] and 1.25 [0.2; 9.4] seconds. Median preoperative CMT was 276.50 [263.25; 289.75] µm and 276.00 [262.00; 290.00] µm. Median postoperative CMT was 278.00 [260.50; 288.00] versus 275.50 [264.00; 290.50] µm at 1 week, 279.50 [266.75; 292.25] versus 280.00 [266.50; 294.50] µm at 3 weeks and 280.50 [268.00, 293.75] versus 279.50 [264.75; 295.25] µm at 6 weeks. Differences in CMT and total macular volume between the groups were not statistically significant at any point in time.

CONCLUSION

Femtosecond laser (FSL) prefragmentation of the nucleus into six sectors did not reduce US energy consumption compared with manual splitting of the nucleus into four quadrants in this particular surgical setting. Sectorial FSL-prechopping with the low-energy FSL used had no additional impact on postoperative macular thickness and volume.

Precision pulse capsulotomy: performance metrics and utility in routine and complex cases

PURPOSE

To evaluate precision pulse capsulotomy (PPC) performance.

SETTING

University and private practice in the United States and South Korea.

DESIGN

Multicenter retrospective analysis.

METHODS

The surgical videos of 337 cataract surgeries with PPC capsulotomy performed by 4 surgeons at 4 centers were used to assess capsulotomy outcomes including completion rate, diameter, roundness (ovality), and quality of capsular overlap.

RESULTS

PPC use resulted in 99.4% free-floating capsulotomies from 337 cases. Video image analysis in a subset (n = 52) yielded a mean capsulotomy diameter of 5.0 mm ± 0.16 mm SD (95% CI, 4.96-5.04 mm). Capsulotomies were round to slightly oval at the end of the case with a mean ovality of 3.0% ± 2.86% (95% CI, 2.22%-3.78%; 360 degrees capsular overlap was obtained in 98% of cases. The offset of the capsulotomy center with the intraocular lens (IOL) optic center was 197 μm ± 122 μm (SD) (95% CI, 148-246 μm). PPC was used successfully in traumatic cataracts with compromised anterior and posterior capsule, phacodonesis, intumescent cataract with constricted pupil, and zonular dialysis and in penetrating keratoplasty with open-sky extracapsular cataract extraction.

CONCLUSIONS

Surgeons obtained good PPC capsulotomy outcomes in routine and challenging cases. Little variation was observed in achieving free-floating capsulotomies with approximately 5.0 mm diameter and complete capsular overlap. Variation was observed in the amount of offset between the capsulotomy center and the center of the IOL optic. PPC was useful in cases with multiple comorbidities that challenge capsulotomy performance.

Clinical outcomes and complications between FLACS and conventional phacoemulsification cataract surgery: a PRISMA-compliant Meta-analysis of 25 randomized controlled trials

AIM

To update and investigate the clinical outcomes and complications between femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification cataract surgery (CPCS).

METHODS

A Meta-analysis was performed using databases, including Pubmed, Embase, and the Cochrane library. At least one of the clinical outcomes and/or complications data in each included randomized controlled trials (RCT) was reported. The quality of the RCT was assessed with the Cochrane risk assessments tool.

RESULTS

Overall, 25 RCTs including 3781 eyes were included. No statistically significant difference detected between FLACS and CPCS in terms of corrected distant visual acuity (CDVA), uncorrected distant visual acuity (UDVA), and central corneal thickness (CCT) at the long-term follow up, although FLACS showed better CDVA at 1wk postoperatively, and less increase in CCT at 1d and 1wk. FLACS had better postoperative endothelial cell count (ECC) at 1 and 4-6wk, while there was no significantly difference between FLACS and CPCS at 1d, 3 and 6mo [weighted mean difference (WMD): 51.54, 95% confidence interval (CI): -5.46 to 108.54, P=0.08; WMD: 48.52, 95%CI: -17.54 to 114.58, P=0.15; WMD: 12.17, 95%CI: -48.61 to 72.94, P=0.69, respectively]. Postoperative endothelial cell loss (ECL) of the FLACS was significantly lower than that of the CPCS at 1, 4-6wk, and 3mo (P=0.02, 0.008, 0.03, respectively). However, there was no significant difference between two groups at 6mo (WMD: -30.36, 95%CI: -78.84 to 18.12, P=0.22). No significant difference was discovered with respect to the macular edema [odds ratio (OR): 0.93, 95%CI: 0.42 to 2.05, P=0.85], capsular complication excluding posterior capsular tears (OR: 0.79, 95%CI: 0.42 to 1.50, P=0.47) and intraocular pressure change (OR: 0.82, 95%CI: 0.39 to 1.72, P=0.60). However, posterior capsular tears were more common in CPCS group (OR: 0.12, 95%CI: 0.01 to 0.98, P=0.05). The effective phacoemulsification times were significantly lower in the FLACS group compared to the CPCS group (WMD: -0.78, 95%CI: -1.23 to -0.34, P=0.0006).

CONCLUSION

No statistically significant difference is discovered between FLACS and CPCS in clinical outcomes at the long-term follow up. However, higher rate of posterior capsular tears is detected in patients receiving CPCS.

Femtosecond Laser Assisted Cataract Surgery: A Review

Femtosecond laser assisted cataract surgery (FLACS) offers a level of precision, accuracy and customization that is not possible with manual phacoemulsification (MP). With the increase of patient expectations and premium intraocular lens utilization in the era of refractive cataract surgery, predictability and accuracy has become of utmost importance. FLACS has four main functions: creation of a consistently sized round capsulotomy, treatment of keratometric astigmatism with arcuate incisions, construction of clear corneal incisions, and fragmentation and/or softening of the lens. However, FLACS may have limitations due to suction loss, incomplete capsulotomy or poor pupillary dilation. Patient selection and surgeon experience is critical. This review article will focus on the various platforms available for FLACS, the steps in cataract surgery it can perform, and overall advantages and limitations of the technology.

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.

Cystoid Macular Edema Following Cataract Surgery with Low-Energy Femtosecond Laser versus Conventional Phacoemulsification

Purpose

To compare postoperative changes in central subfield macular thickness (CSMT) and prevalence of cystoid macular edema (CME) in patients undergoing cataract surgery with low-energy femtosecond laser versus standard phacoemulsification.

Design

This was a retrospective comparative real-world study.

Methods

Postoperative data of 252 eyes of 165 patients were collected: 138 eyes received low-energy femtosecond laser-assisted cataract surgery (FLACS) and 114 eyes underwent conventional phacoemulsification cataract surgery (CPCS). Postoperative changes in CSMT and prevalence of CME were compared between the two groups.

Results

There was a significant increase in mean CSMT from preoperative to postoperative values at 2.5 months in both the FLACS and CPCS group (p<0.001). Mean change (preoperation to 2.5 months postoperation) in CSMT was 6.2±11.5 µm in the FLACS group and 7.3±26.6 µm in the CPCS group, which was statistically significant but clinically not relevant. Comparison of mean changes in CSMT (preoperation to 2.5 months postoperation) between the FLACS and CPCS groups revealed no significant differences. The rate of pseudophakic CME (PCME) development was lower in the FLACS group (1.4%) than the CPCS group (4.4%; p=0.247). When using PREMED criteria to define clinically significant PCME, only 0.7% patients in the FLACS group and 1.8% in the CPCS group showed development of clinically significant PCME (p=0.586).

Conclusion

The mean change in CSMT and occurrence of postoperative CME was lower in the low-energy FLACS group than the standard-phacoemulsification group; however, the difference was not statistically significant.

Cytokines, chemokines, and flare in the anterior chamber after femtosecond laser-assisted cataract surgery

PURPOSE

To analyze anterior chamber inflammation after pretreatment with a femtosecond laser platform during cataract surgery and compare the results with those of the manual procedure.

SETTING

Eye Clinic, Department of Surgery and Translational Medicine, University of Florence, Italy.

DESIGN

Prospective case series.

METHODS

Aqueous humor was collected after femtosecond laser pretreatment (femtosecond group) and at the beginning of routine cataract surgery before the primary incision was created (control group). The levels of 14 cytokines and chemokines were measured using a multiplex array system. Surgical parameters (suction time, laser time, effective phacoemulsification time [EPT]) were recorded. Anterior chamber flare was measured by laser photometry preoperatively and 1 day and 7 days postoperatively.

RESULTS

Each group comprised 20 eyes. The EPT was significantly lower in the femtosecond group than in the control group. In the femtosecond group, the concentrations of IL (interleukin)-6, IL-8, IL-10, IL-12, vascular endothelial growth factor, and interferon-γ were significantly higher than in the control group. Flare in the anterior chamber measured with flare-cell meter was not significantly different between groups at any timepoint. No correlation was found between cytokine concentrations and age in either group and between cytokine levels and suction or laser time and postoperative flare in the femtosecond group. Also, no correlation was found between postoperative aqueous flare and EPT in either group.

CONCLUSIONS

Despite the rise of proinflammatory cytokines in the aqueous humor after femtosecond laser pretreatment, the anterior chamber flare after cataract surgery was similar to that in controls. This might be a result of the lower EPT required after pretreatment.

The influence of surgeons and technicians on the learning curve of femtosecond-laser cataract surgery

PURPOSE

To demonstrate the influence of the surgeon's and the operating room (OR) technicians' experience upon the outcome of femtosecond laser-assisted cataract surgery (FLACS).

MATERIALS AND METHODS

Our study included 250 eyes from 156 patients who had undergone either cataract surgery or clear-crystalline-lens extraction and where capsulorhexis and lens fragmentation had been performed using the CATALYS® Precision System femtosecond platform (Abbott Medical Optics Inc., Santa Ana, CA, USA).The patients were operated either by an experienced surgeon in the use of femtosecond laser or by an inexperienced surgeon in that field and two technicians. The quantitative outcome measures were: Suction loss rate, vacuum time, number of consumables used by the patient and intraoperative complication rate.

RESULTS

Both for the experienced and the inexperienced surgeons, suction loss rates as well as vacuum time decreased progressively as time went by and more surgical procedures had been completed by that surgeon. For a given surgeon suction time decreased significantly, going from 137 to 99s, as the assisting technician gradually gained experience. The number of consumables used in each procedure by the experienced surgeon ranged from 1.10 (for the first 50 cases) to 1.02 from those initial cases onwards. Regarding intraoperative complications, they also decreased progressively as the number of procedures completed by the surgeon increased.

CONCLUSIONS

The experience of each team member involved in such procedures-be it surgeons or technicians-have an impact, to a greater or lesser extent, upon the surgery's outcome, as quantified by the outcome variables of choice.

Comparable effects on tear film parameters after femtosecond laser-assisted and conventional cataract surgery

Purpose

Dry eye symptoms after conventional cataract surgery are a very common problem. Until now, only few data are available on objective tear film parameters in regard to femtosecond laser-assisted cataract surgery (LCS). Aim of this study was therefore to analyze and compare tear film parameter changes between LCS and conventional cataract surgery.

Methods

A consecutive group of 34 patients, scheduled for cataract surgery, were randomly selected for either LCS or conventional cataract surgery (17 patients/group). Tear film assessments including tear film osmolarity, Schirmer test, MMP-9 analysis via quantitative ELISA, corneal sensitivity, corneal fluorescein staining, and conjunctival fluorescein staining were sequentially evaluated pre- as well as 1 and 3 months postoperatively.

Results

Both groups showed no significant difference in baseline characteristics. All surgeries were performed without any complications. After 1 and 3 months, there was no statistically significant difference in regard to tear film osmolarity (1 month: p = 0.81, 3 months: p = 1.0), Schirmer test (1 month: p = 0.35, 3 month: p = 0.08), and MMP-9 concentration (1 month: p = 0.36, 3 month: p = 0.28) between the two groups.

Conclusions

Neither LCS nor conventional cataract surgery affected objective tear film parameters significantly during our 3-month postoperative observation period. Hence, both surgical techniques can be equally used to treat patients without prior dry eye symptoms.

New IOL formula using anterior segment three-dimensional optical coherence tomography

This retrospective study was aimed to compare prediction errors from various combinations of biometric data generated using optical coherence tomography (OCT) and develop a new intraocular lens (IOL) formula using biometric data. 145 eyes from 145 patients who underwent femtosecond laser-assisted cataract surgery (FLACS) were enrolled to the present study and they were divided into a training set (n = 92) and a test set (n = 53). Preoperative axial length (AL) and corneal radius were measured using partial coherence interferometry. The anterior chamber depth (ACD), lens meridian parameter (LMP), lens thickness (LT), thickness of anterior and posterior parts of the crystalline lens (aLT and pLT), and anterior segment length were measured by OCT. From a training set, we developed eight regression equations and analyzed the predictive accuracy. The regression equation using AL, LMP, and pLT (-1.143 + 0.148*AL + 0.428*LMP + 0.254*pLT) showed the strongest correlation with effective lens position (ELP) and smallest standard deviation of ELP prediction error. IOL formula generated using AL, LMP, and pLT yielded the highest predictive accuracy. In a test set, the new IOL formula also produced narrowest range of prediction error, smallest median absolute error, and highest percentages within ±0.25, ±0.50 than existing IOL formulas. The IOL formula considering AL, LMP and pLT will help to improve predictive accuracy in FLACS.

Protective effect of bromfenac sodium on femtosecond laser‑assisted cataract surgery via modulating cyclooxygenase‑2 expression

Cataract is a blinding‑caused disease and affects millions of individuals worldwide. Although conventional phacoemulsification (CPCS) has been widely used for treatment of cataract, the incidence of cataract‑caused blindness still increased year by year. Recently, femtosecond laser technology has been expanded to variety of clinical applications, including cataract surgery. The present study evaluated the curative effect of bromfenac sodium (BS) after femtosecond laser‑assisted cataract surgery (FLACS) and analyzed the mechanism of action. A total of 90 patients were randomly divided into five groups: Group I, conventional phacoemulsification treatment (CPCS) + dexamethasone (DEX)/tobramycin (TOB); group II, CPCS + bromfenac sodium (BS); group III, Femtosecond laser‑assisted cataract surgery (FLACS) + DEX/TOB; group IV, FLACS + BS; and group V, FLACS + pranoprofen. Aqueous humor was collected from these patients post‑surgery. For in vitro studies, SRA01/04 cells were irradiated using UV, followed by the collection of culture media and cell lysate. Prostaglandin E2 (PGE2) levels, an indicator of inflammation, were measured using ELISA both in vivo and in vitro. In addition, cyclooxygenase (COX) and cleaved caspase‑1 p20 expression levels were analyzed using western blotting. The findings suggested that BS was more effective and safer compared with glucocorticoids (GCs) after cataract surgery. BS can protect against post‑operative inflammation by inhibiting PGE2 production. Under in vitro conditions BS prevented the SRA01/04 cells from undergoing apoptosis after UV treatment and also suppressed PGE2 release from UV‑irradiated SRA01/04 cells by modulating COX‑2 expression. Furthermore, BS may have an inhibitory effect on the inflammatory form of cell death. Overall, these results indicated that BS could replace existing GCs as a reliable drug for a perioperative period of cataract surgery. It was also identified that the inhibitory effect of BS on PGE2 production was mediated via the regulation of COX‑2.

[Energy load and state of corneal endothelium in hybrid (femtosecond laser-assisted) and torsional phacoemulsification]

Postoperative state of the corneal endothelium is the most important criterion for evaluating the safety of cataract phacoemulsification.

PURPOSE

To compare the intraoperative energy load and postoperative state of corneal endothelium in hybrid (femtosecond laser-assisted) and torsional phacoemulsification.

MATERIAL AND METHODS

The study analyzed surgical outcomes of 603 patients (714 eyes) divided into 3 groups: 225 patients (267 eyes) underwent modified femtosecond laser-assisted phacoemulsification (1st group), 237 patients (278 eyes) underwent standard femtosecond laser-assisted phacoemulsification (2nd group), and 141 patients (169 eyes) who underwent torsional phacoemulsification (3rd group). The follow-up period lasted up to 2 years.

RESULTS

In patients with grade II lens density (here and further - L. Buratto classification is used), effective ultrasound time was 0.56±0.11 s in the 1st group, 0.83±0.17 s in the 2nd group, and 2.78 ± 0.51 s in the 3rd group (p(1-2)<0.05; p(1-3)<0.05; p(2-3)<0.05). In patients with grade III lens density effective ultrasound time was 2.04±0.37 s in the 1st group, 2.97±0.53 s in the 2nd group, and 4.59±0.91 s in the 3rd group (p(1-2)<0.05; p(1-3)<0.05; p(2-3)<0.05). In patients with grade IV lens density, effective ultrasound time was 3.95±0.81 s in the 1st group, 5.11±1.03 s in the 2nd group, and 8.37±1.73 s in the 3rd group (p(1-2)<0.05; p(1-3)<0.05; p(2-3)<0.05). In patients with grade II lens density, loss of endothelial cells was 3.3±1.1% in the 1st group, 3.7±1.2% in the 2nd group, and 4.3±1.2% in the 3rd group (p(1-2)>0.05; p(1- 3)<0.05; p(2-3)<0.05). In patients with grade III lens density, loss of endothelial cells was 5.1±1.4% in the 1st group, 5.7±1.5% in the 2nd group, 7.2±1.7% in the 3rd group (p(1-2)>0.05; p(1-3)<0.05; p(2-3)<0.05). In patients with grade IV lens density, loss of endothelial cells was 8.9±2.1% in the 1st group, 10.1±2.3% in the 2nd group, and 13.3±2.5% in the 3rd group (p(1-2)>0.05; p(1-3)<0.05; p(2- -3)<0.05).

CONCLUSION

Both techniques of femtosecond laser-assisted phacoemulsification significantly reduce the effective ultrasound time (p<0.05) and the degree of corneal endothelial cells loss (p<0.05) compared with torsional phacoemulsification.

Changes in Pupil Area during Low-energy Femtosecond Laser-assisted Cataract Surgery

Purpose

To study the potential changes in pupil area within low-energy femtosecond-laser assisted cataract surgery (FLACS).

Methods

A retrospective assessment of the pupil size was performed in the eyes undergoing FLACS using the Ziemer LDV Z8. We measured the pupil diameters as part of the images taken preoperatively and at the completion of laser pretreatment (after releasing the suction). We calculated the pupil area in 40 eyes of 40 patients (14 right and 26 left eyes). The mean ± standard deviation (SD) of age of the patients was 74 ± 7.4 years (range: 51-87). Paired t-test was used for statistical analyses. Subgroups were built with reference to age and preoperative pupil area (smaller than or equal to the median versus larger than the median).

Results

The mean ± SD axial length, anterior chamber depth, white-to-white distance and lens thickness were 24.01 ± 1.47, 3.23 ± 0.4, 11.97 ± 0.49, and 4.59 ± 0.41 mm, respectively. The mean ± SD pupil area was 39.33 ± 7.1 mm 2 preoperatively and 39.3 ± 6.75 mm 2 after laser pretreatment. The mean ± SD change in pupil area was -0.03 ± 2.12 mm 2 . There were no statistically significant changes between preoperative and post-laser pupil areas (P = 0.93, 95% CI: -0.71 to 0.65). Comparisons within subgroups also did not detect pupil area reduction.

Conclusion

This study did not detect statistically significant changes in pupil area after laser pretreatment using low-energy FLACS. This observation is in contrast to previous studies using other laser platforms.

Performance of femtosecond laser-assisted cataract surgery in Chinese patients with cataract: a prospective, multicenter, registry study

BACKGROUND

This study aimed to investigate the completion rate, visual performance, and adverse outcomes of femtosecond laser-assisted cataract surgery (FLACS) in Chinese patients.

METHODS

This is a prospective, single-arm, multicenter registry study of 19 cataract surgery clinics in China. Chinese patients with cataract who underwent FLACS using the Alcon LenSx® laser system in single eye (n = 1140) or both eyes (n = 201) were enrolled and data were collected between March 2015 and August 2016. Clinical characteristics were recorded before surgery, and on postoperative days 1, 7, and 30. For surgery on both eyes, the second eye was included in the analysis only if it was operated within 30 days after the first eye surgery. The primary outcome was the completion rate of circular anterior capsulotomy. Secondary outcomes for lens fragmentation, corneal incision, and intraocular lens (IOL) implantation included best corrected distance visual acuity (BCDVA) and completion rates. Adverse events (AEs) were recorded.

RESULTS

The completion rates of circular anterior capsulotomy, lens fragmentation, corneal incision, and IOL implantation were 98.6% (95% CI: 97.8-99.1%), 99.5% (95% CI: 99.1-99.8%), 97.6% (95% CI: 96.7-98.3%), and 100% (95% CI: 99.8-100%), respectively. BCDVA preoperatively and at postoperative day 30 were 1.134 ± 0.831 logMAR and 0.158 ± 0.291 logMAR, respectively. The proportion of eyes with BCDVA of 20/20 or better was 1.6% at baseline and 41.3% at postoperative day 30. AE incidence was 0.32%, with posterior capsule rupture present in 0.19% of eyes.

CONCLUSION

FLACS using the LenSx® laser system can achieve satisfactory results in a real-world setting.

Architecture evaluation of the main clear corneal incisions in femtosecond laser-assisted cataract surgery by optical coherence tomography imaging

Purpose

To assess the stability and reliability of femtosecond laser-assisted cataract surgery (FLACS) incisions design and dimensions using anterior segment optical coherence tomography (AS-OCT) imaging.

Setting

Renato Ambrósio Ophthalmologic Study Center from Hospital Oftalmológico de Brasília, Brasília, Brazil.

Design

Prospective nonrandomized controlled case series.

Methods

Eyes undergoing FLACS with triplanar main temporal clear corneal incision (CCI) were evaluated at the end of the case. Eyes that required any incision hydration, surgical complications or lacked follow-up were excluded. The AS-OCT was performed after femtosecond delivery; at the end of the case; at 1 day and at 30 days after surgery. Data of pachymetry, endothelial and epithelial gaps, Descemet detachment and CCI architecture were compared.

Results

Eleven eyes from 11 patients completed follow-up. Corneal thickness was statistically different between after femtosecond delivery and the end of the case (P-value <0.05), but without difference compared to 30 days evaluation. There was an increase of Descemet detachments (P-value <0.05) and endothelial gaps (P-value =0.0133) at the end of the case compared to post-femtosecond delivery. As for the architecture of the CCI, significant difference was found between the parameters of entry angle and exit angle measured with AS-OCT and the programmed.

Conclusion

The AS-OCT was capable of visualizing changes in the cornea at the CCI. Despite the stress caused by manipulation, results indicated good stability of incision and reproducibility of tunnel length.

Synopsis

Difference of corneal thickness at the CCI between after femtosecond and after phacoemulsification measurements (P-value <0.05), with increase of endothelial gaps (P-value =0.0133) and Descemet detachments (P-value <0.05).

Cataract surgery and lens implantation

PURPOSE OF REVIEW

This review aims to introduce recent updates in cataract surgery and lens implantation.

RECENT FINDINGS

Compared to phacoemulsification, femtosecond laser-assisted cataract surgery (FLACS) may offer benefit for cataract patients with other complicated ocular diseases, such as corneal disease and vitreous abnormalities. Meanwhile, several types of novel intraocular lenses (IOLs) have been introduced to the market, and each of them has particular features in improving patients' visual acuity. In addition, based on a series of studies, multifocal IOL is superior to monofocal IOL when it comes to providing a better visual correction at different distances. Furthermore, a research group has introduced a new approach for cataract surgery - all laser surgery (FLACS band with nanolaser emulsification), which can effectively reduce iatrogenic trauma to the cornea. Also, a novel technique designed for children can lessen damage from cataract surgery.

SUMMARY

Based on previous studies, we summarize the new proceedings in FLACS and the indications for applying multifocal or toric IOL. In addition, we briefly introduce a new approach to cataract surgery - all laser surgery (FLACS band with nanolaser emulsification), and a less invasive surgical procedure used in pediatric cataract patients.

Comparison of diathermic high-frequency capsulorhexis and continuous curvilinear capsulorrhexis in white cataract surgery

AIM

To compare the corneal endothelial cell counts pre- and post-operation, ultrastructure of anterior lens capsule and surgical completion after diathermic high-frequency capsulorhexis (DHC) and continuous curvilinear capsulorrhexis (CCC) applied in phacoemulsification (PHACO) of white cataract surgery.

METHODS

Sixty-six eyes of 66 patients (33 males and 33 females) with cataract aged between 60 and 80y (mean 72.5±5.5) were recruited and undergone the surgery from June 2014 to November 2016. Anterior lens capsule, derived from two kinds of capsulorhexis, were randomly divided into two groups according to random number table. The ultrastructure of the capsule edge and its closer tissue were observed by transmission electron microscopy (TEM) and optical microscopy respectively. The surgical completion conditions and corneal endothelial cell counts were analyzed pre- and post-operation after two capsulorhexis.

RESULTS

The capsule derived from CCC had smooth edge, well-organized cellular structure and the cells filling into the cutting edge under TEM and optical microscopy. The capsule derived from DHC had an approximate 60 banded area of cell degeneration and necrosis, with dentiform prominences at the edge of the capsule, and no cell structure was observed at this area. The corneal endothelial cell counts of both groups were slightly declined 1wk post-operation compared with that of pre-operation. There was no statistical difference between the two groups (t=1.63, P>0.05).

CONCLUSION

DHC shows good clinical value in white mature and hypermature cataract surgery.

Managing the posterior polar cataract: An update

Posterior polar cataracts (PPC) have always been a challenge for cataract surgeons due to their inherently higher propensity for posterior capsule rupture. Over the years, several technical modifications have been suggested to enhance safety and reduce posterior capsule rupture rates in these polar cataracts. This review article tries to present the various techniques and strategies to published in literature to manage PPCs. It also discusses pearls for making surgery more reproducible and consistent, as well as the role of newer diagnostic and surgical technology based on the published literature on the subject.

Comparison of cumulative dissipated energy delivered by active-fluidic pressure control phacoemulsification system versus gravity-fluidics

PURPOSE

To compare the cumulative dissipated energy (CDE), aspiration time and estimated aspiration fluid utilized during phacoemulsification cataract surgery using two phacoemulsification systems .

METHODS

A total of 164 consecutive eyes of 164 patients undergoing cataract surgery, 82 in the active-fluidics group and 82 in the gravity-fluidics group were enrolled in this study. Cataracts graded NII to NIII using LOCS II were included. Each subject was randomly assigned to one of the two platforms with a specific configuration: the active-fluidics Centurion ^® phacoemulsification system or the gravity-fluidics Infiniti ^® Vision System. CDE, aspiration time (AT) and the mean estimated aspiration fluid (EAF) were registered and compared.

RESULTS

A mean age of 68.3 ± 9.8 years was found (range 57-92 years), and no significant difference was evident between both groups. A positive correlation between the CDE values obtained by both platforms was verified (r = 0.271, R ² = 0.073, P = 0.013). Similarly, a significant correlation was evidenced for the EAF (r = 0.334, R ² = 0.112, P = 0.046) and AT values (r = 0.156, R ² = 0.024, P = 0.161). A statistically significantly lower CDE count, aspiration time and estimated fluid were obtained using the active-fluidics configuration when compared to the gravity-fluidics configuration by 19.29, 12.10 and 9.29%, respectively (P = 0.001, P < 0.0001 and P = 0.001).

CONCLUSIONS

The active-fluidics Centurion ^® phacoemulsification system achieved higher surgical efficiency than the gravity-fluidics Infiniti ^® IP system for NII and NIII cataracts.