Intraoperative performance and postoperative outcome comparison of longitudinal, torsional, and transversal phacoemulsification machines

Comparison of Phacoemulsification Grooving Efficiency in Longitudinal vs Transversal Handpieces

Purpose

To determine the difference, if any, in grooving efficiency at various settings on the Whitestar Signature Pro phacoemulsification (phaco) system.

Methods

Cataractous lenses were simulated by exposing porcine lenses to formalin for 2 hours. A total of 120 lenses were analyzed at various power settings on both longitudinal and transversal handpieces. Twenty trials each were performed with power set to 25%, 50%, and 75% on both handpieces. A Whitestar Phaco Handpiece System was used to provide longitudinal power, and a Whitestar Signature Ellipsis Handpiece provided transversal power. Lenses were placed within a plastic chamber and grooved by an investigator blinded to settings. A second investigator recorded times and adjusted settings. The Whitestar Signature Pro phaco system was used for grooving.

Results

There was no significant difference in grooving times between the longitudinal and transverse handpieces at any power setting (P > 0.05). There was a significant decrease in grooving times when comparing the 25% power setting with the 75% power setting for the transversal handpiece (P=0.021).

Conclusion

Both longitudinal and transversal handpieces on the Whitestar Signature Pro phaco system produce similar results to one another at each power setting. There is a general trend toward shorter grooving times, reflecting greater efficiency, at higher power settings. Grooving efficiency on the transversal handpiece may be more affected by changes in the power settings as compared with the longitudinal settings.

Comparative anatomical outcomes of high-flow vs. low-flow phacoemulsification cataract surgery: A systematic review and meta-analysis

Background

Phacoemulsification is an effective and widely performed technique in cataract surgery, but the comparative anatomical outcomes, including endothelial cell loss (ECL), central corneal thickness (CCT), and central macular thickness (CMT), between high-flow and low-flow phacoemulsification cataract surgery remain unclear.

Methods

This study followed Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) Statement. Random-effects models were applied to measure pooled mean differences (MD) with 95% confidence intervals (CI) of anatomical outcomes between high-flow and low-flow phacoemulsification cataract surgery. We judged overall certainty of evidence (CoE) based on Grading of Recommendations Assessment, Development and Evaluation (GRADE) criteria.

Results

We included six randomized controlled trials (RCTs) totaling 477 participants. The meta-analysis showed similar changes associated with these two surgery types in both ECL at postoperative days 2–14 (MD: −1.63%; 95% CI: −3.73 to 0.47%; CoE: very low), days 15–42 (MD: −0.65%; 95% CI −2.96 to 1.65%; CoE: very low) and day 43 to month 18 (MD: −0.35%; 95% CI: −1.48 to 0.78%; CoE: very low), and CCT at postoperative day 1 (MD: −16.37 μm; 95% CI: −56.91 to 24.17 μm; CoE: very low), days 2–14 (MD: −10.92 μm; 95% CI: −30.00 to 8.16 μm; CoE: very low) and days 15–42 (MD: −2.76 μm; 95% CI: −5.75 to 0.24 μm; CoE: low). By contrast, low-flow phacoemulsification showed less increase in CMT at postoperative days 15–42 (MD, −4.58 μm; 95% CI: −6.3 to −2.86 μm; CoE: low).

Conclusions

We found similar anatomical outcomes, except in CMT, for both high-flow and low-flow phacoemulsification cataract surgery. Future head-to-head RCTs on visual outcomes should confirm our findings.

Systematic review registration

PROSPERO, identifier: CRD42022297036.

Morphological variations influencing the outcomes in posterior polar cataract

Purpose

To study the intraoperative complications and postoperative clinical outcomes in different types of posterior polar cataract (PPC) following phacoemulsification, based on morphological classification.

Methods

All consecutive patients with PPC who underwent phacoemulsification during the study period from 2016 to 2019 were included and sub-grouped based on the morphological characteristics according to Daljit Singh's classification. Intraoperative complications such as posterior capsular rupture (PCR), vitreous loss, nucleus drop, and Postoperative best-corrected visual acuity (BCVA) at day 1 and day 30 were documented.

Results

A total of 388 eyes of 380 patients were included. Eighty nine (22.9%) eyes belonged to type 1, 135 (34.8%) belonged to type 2, 8 (2.1%) belonged to type 3, and 156 (40.2%) belonged to type 4. Thirty-five (9.3%) eyes had intraoperative PCR, with vitreous loss in 21 (60%) eyes, and nucleus/cortex drop in 5 (1.3%) eyes. Six (75%) eyes of type 3, 14 (10.04%) eyes of type 2, 12 (17.7%) eyes of type 4, and 3 (3.4%) eyes of type 1 PPC had PCR. PCR occurred more during the emulsification of the nucleus (18 cases, 51.4%). A significant correlation was seen between intraoperative PCR and type of PPC with a higher incidence in type 3 (P < 0.001). BCVA was found to be significantly worse on day 1 among patients with PCR compared to those who did not and improved well by day 30.

Conclusion

PPC morphology is significantly co-related with the occurrence of PCR, emphasizing the need for careful grading of posterior polar cataracts in predicting the risk of intraoperative complications.

Comparison of effective phacoemulsification time and corneal endothelial cell loss using three different ultrasound frequencies: A randomized controlled trial

Purpose

Comparison of three ultrasound (US) frequencies for phacoemulsification of hard cataracts to determine a frequency that makes phacoemulsification more efficacious and safer.

Methods

A randomized controlled trial was undertaken at a medical college and hospital. In total, 207 patients with grade 5.6-6.9 (LOCS III) senile cataract were randomized into three groups. Group I underwent phacoemulsification with 28-kHz frequency, group II with 42-kHz frequency, and group III with 53-kHz frequency. The effective phacoemulsification time (EPT) and estimated fluid usage (EFU) were compared intraoperatively. The endothelial cell parameters were analyzed for 6 months.

Results

The groups were matched for age (P = 0.467), gender (P = 0.497), nuclear grade (P = 0.321), and anterior chamber depth (P = 0.635). The EPT and EFU were significantly lower in group III, compared to group II and group I, with P < 0.0001 and P < 0.0001, respectively. Postoperatively, the endothelial cell density (ECD) was significantly higher in group III at 1 month (P < 0.0001), 3 months (P < 0.0001), and 6 months (P < 0.0001). The percentages of ECD loss were also significantly lower in group III; the difference was statistically significant (P < 0.0001) up to 6 months postoperatively.

Conclusion

Higher frequency ultrasound was associated with a lower EPT and EFU as well as better endothelial preservation than lower frequencies in hard cataracts.

Efficient use of ultrasound in cataract surgery

PURPOSE OF REVIEW

Modern phacoemulsification machines apply ultrasound through a variety of settings and parameters to remove a cataract. Using these new technologies efficiently is critical for both reducing surgical times and improving postoperative outcomes. The present article reviews recent findings in phacodynamics to explore the optimum use of ultrasound in cataract surgery.

RECENT FINDINGS

In studies seeking to determine the optimum parameters in both fluidics and power, increased power and aspiration does not necessarily equate to more efficiency. New developments, such as torsional ultrasound, micropulse, and burst mode have shown increased efficiency in randomized control trials and in-vitro compared with conventional ultrasound. Regarding vacuums, the venturi pump has demonstrated greater efficiency compared with the peristaltic pump. We also explore other parameters, such as chamber pressure and tip selection. Meta-analyses on femtosecond-laser assisted cataract surgery (FLACS) have shown similar long-term visual outcomes compared to conventional cataract surgery.

SUMMARY

Though conventional cataract surgery remains highly effective, surgeons have increasing options for customizing their ultrasound settings and phacoemulsification techniques.

Comparison of Femtosecond Laser-Assisted Cataract Surgery and Conventional Phacoemulsification on Endothelial Cell Density When Using Torsional Modality

Purpose

To compare the effects of femtosecond laser assisted cataract surgery (FLACS) and manual phacoemulsification on cumulative dissipated energy (CDE), torsional amplitude, and endothelial cell density (ECD).

Patients and Methods

This prospective, randomized study was conducted at Oka Eye Clinic (Fukuoka, Japan). Surgeries were performed using FLACS (with LenSx) or conventional technique in adults ≥20 years with grade 2–4 cataracts. Visits included preoperative, surgery day, and 5 postoperative visits (days 1, 4–10, 20–40, 60–120, and 150–210). Primary endpoint was CDE. Secondary endpoints included ECD percent change at day 150–210 versus preoperative visit and average torsional amplitude on surgery day. Exploratory endpoints included central corneal thickness and corrected distance visual acuity (CDVA). Superiority of FLACS to conventional technique was evaluated using t-tests based on a mixed model for repeated measures.

Results

Full analysis set included 53 eyes per group. Mean cataract grade was 2.92±0.58 in FLACS and 2.94±0.57 in conventional group. FLACS versus conventional method had significantly lower mean CDE (0.213±0.334 versus 1.718±0.898%-seconds, respectively; P<0.0001), demonstrating superiority of FLACS. Low endothelial cell loss (ECL) was achieved with both FLACS and conventional methods (1.5±5.6% and 2.7±5.2%; P=0.260). Torsional amplitude was significantly lower for FLACS versus conventional method (19.6±16.0% versus 31.1±6.6%; P<0.0001). Central corneal thickness was comparable for both methods at all visits except day 1; CDVA was comparable for both methods at all postoperative visits.

Conclusion

FLACS achieved significantly lower CDE compared with the conventional surgical method (P<0.0001). Low ECL was achieved with both FLACS (1.5%) and conventional (2.7%) methods.

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Retrospective Comparison of Intraoperative Parameters, Efficacy and Safety in Cataract Surgery Between Halogen and Light-Emitting Diode (LED) Illuminated Surgical Microscope

Purpose

The objective was to compare the operative time, ultrasound time, efficacy and safety of phacoemulsification with IOL insertion between using halogen and light-emitting diode (LED) illuminated microscope.

Patients and Methods

Two hundred and twenty-seven surgical charts of cataract patients who underwent phacoemulsification with IOL insertion between June 2018 and October 2020 were reviewed. There were 113 cases operated on under halogen-illuminated microscope (Carl Zeiss OPMI LUMERA S7^®) and 114 cases operated on under light-emitting diode (LED)-illuminated microscope (Leica PROVEO 8^®). All cases were operated on by the same surgeon (S.T.). The difference in operative time and ultrasound time between two groups was compared by independent samples t-test. The proportion of cases with 3-months BCVA that was better than 20/30 and the proportion of cases with intraoperative complications from the operation between two groups were compared by Pearson’s Chi-squared test.

Results

The mean ultrasound time was 121.29±53.60 seconds in halogen group and 123.98±61.53 seconds in LED group. The mean difference was −2.69±8.44 seconds which was not statistically significant (95% CI, −19.35 to 13.97; p=0.573). The mean operative time was 19.83±4.77 minutes in the halogen group and 17.20±3.02 minutes in the LED group. The mean difference was 2.63±0.53 minutes (95% CI, 1.59 to 3.67; p < 0.001). The cases with BCVA better than 20/30 was 93.69% in halogen group and 95.49% in LED group. The proportion of cases with intraoperative complications was 3.53% in halogen group and 2.63% in LED group. The difference of both proportions was not statistically significant (p=0.553 and p=0.692, respectively).

Conclusion

This study shows statistically significant operative time reduction with LED microscope. This evidence could be used for making the decision to switch from halogen microscope to LED microscope. Upgrading to LED-illuminated microscope might be beneficial for productivity improvement if there were at least six to seven cases operated on per day. The ultrasound time, efficacy, and safety showed no significant difference.

A Novel Piezoelectric Ceramic Actuator with Scissoring Composite Vibration for Medical Applications

This paper presents a novel scissoring composite actuator which can successfully degenerate longitudinal vibration into scissoring vibration at actuator tips for potential medical applications. The proposed actuator consists of back mass, multilayer piezoceramic stack, front mass with netted pre-stress structure and beam. The actuator is driven by only a small axially poled multilayer piezoceramic stack. Moreover, a special symmetrical grooved structure is designed at the beam end to convert longitudinal driving vibration into opposite bending vibrations at the beam tip, resulting in scissoring-type composite vibration. The converted scissoring vibration concentrates on the beam tip without any deflection along other parts, which is highly desirable for narrow-spaced medical operations. The proposed design principle is demonstrated by structural analysis and verified by different types of finite element modeling (FEM) simulations, including Eigen frequency analysis, harmonic analysis, and transient analysis. The results reveal the design effectiveness of the actuator’s structure on scissoring-type mode excitation. Finally, a prototype of the proposed piezoelectric actuator is fabricated and tested, rendering superior performance and highly reliable mode conversion. The proposed actuator exhibits potential for advanced medical applications.

Effect of balanced phacoemulsification tip on the outcomes of torsional phacoemulsification using an active-fluidics system

PURPOSE

To compare the outcomes of torsional phacoemulsification with a new balanced tip (Intrepid) and a conventional tip (Kelman) using a single active-fluidics torsional phacoemulsification machine (Centurion).

SETTING

Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical Sciences, New Delhi, India.

DESIGN

Prospective comparative case-control study.

METHODS

Patients with senile cataract had torsional phacoemulsification with the Kelman conventional tip or the new Intrepid balanced tip using the active-fluidics torsional machine. Intraoperative parameters, such as cumulative dissipated energy (CDE), total ultrasound (US) time, torsion use time, torsion amplitude, aspiration time, and fluid use, were noted and compared. Endothelial cell loss and central corneal thickness (CCT) changes were evaluated at 1 month.

RESULTS

The new tip showed significantly less CDE, total US time, torsion amplitude, aspiration time, and fluid use (8.55 ± 6.9 [SD], 33.59 ± 28.12 seconds, 37.8 ± 13.42, 173.19 ± 47.26 seconds, and 66.59 ± 20.44 mL, respectively) than the conventional tip (13.47 ± 10.65, 42.8 ± 33.46 seconds, 42.58 ± 16.38, 202.25 ± 71.28 seconds, and 97.14 ± 36.86 mL, respectively) (P < .01), especially in higher grades of cataract. Anterior capsulorhexis margin tear occurred in 2 patients with the new tip. There were no corneal burns in either group. The mean endothelial cell loss and the percentage change in CCT were not significantly different at 1 month.

CONCLUSIONS

The new balanced tip performed phacoemulsification more efficiently, especially in hard cataracts requiring higher energy and prolonged phacoemulsification time.

Determining optimal ultrasound percent on time with long-pulse torsional phacoemulsification

OBJECTIVE

To evaluate the optimum percent on time for the most efficient lens fragment removal using long-pulse torsional ultrasound (US).

DESIGN

In vitro laboratory study.

METHODS

Porcine lens nuclei were incubated in formalin for 2 hours and then cut into 2 mm cubes. Phacoemulsification was performed using the Centurion^® Vision System and Infiniti OZil handpiece with the balanced tip. Vacuum was set at 500 mm Hg, aspiration rate at 50 mL/min, and intraocular pressure (IOP) at 50 mm Hg. Pulse rate was 26 pulses/second. Studied parameters were percent power: 60%, 80%, and 100%, and percent on times: 50%, 60%, 70%, and 80%. Efficiency was the total time for a cube to be emulsified. Chatter was the number of times the lens fragment bounced off the tip.

RESULTS

There was no significant difference in efficiency between 50%, 60%, and 70 % on-time settings (p = 0.17 and 0.08, respectively); however, there was significant increase in efficiency when the on time was increased from 70% to 80% (p = 0.03). Increasing power from 60% to 100% showed a statistically significant efficiency increase (p = 0.001). There was no significant change in chatter with increasing on time; however, there was a statistically significant increase in chatter with every power level increase.

CONCLUSION

Increasing on-time percent does not improve efficiency under torsional long-pulse US. There is no significant change in chatter with increasing on-time percent. Increasing power increases efficiency despite chatter increase. Long-pulse US does not appear to influence torsional action in a clinically meaningful way.

Prospective randomized comparative study between venturi and peristaltic pumps in WhiteStar Signature® phacoemulsification machine

Purpose

To compare intraoperative parameters between venturi and peristaltic pump in WhiteStar Signature^® phacoemulsification machine using the bevel-down technique.

Setting

Hospital Oftalmológico de Brasília, Brasília, Federal District, Brazil.

Design

Prospective, comparative, patient-masked study.

Methods

Three hundred eyes were randomly assigned to have a phacoemulsification procedure with WhiteStar Signature^® using either peristaltic (n=150 eyes) or venturi (n=150 eyes) pumps by a single surgeon (WTH). Elliptical ultrasound setting and prefracture (prechop or preslice) techniques were used in all cases. Cataract nucleus density was graded using lens opacities classification system III and Pentacam Nucleus Staging classification. Clinical measurements included preoperative- and postoperative- corrected visual acuity, preoperative and 2-month postoperative endothelial cell counts, and preoperative and 1-day postoperative central corneal thickness. Intraoperative measurements at the end of the case were phaco time, fluid used, total case time, and Efx energy.

Results

There were no statistically significant differences between groups regarding age, cataract density, and phaco time (P>0.05). Intraoperatively, we observed significantly less ultrasound energy (P=0.011), case time (P=0.0001), and balanced saline solution (P=0.001) usage in the venturi group. Clinically, both fluidic settings can provide similar clinical outcomes and visual recovery, regarding corrected distance visual acuity, endothelial cell count, and central corneal thickness.

Conclusion

Our data show that to minimize fluid use, case time, and energy with the prefracture technique, the venturi pump was the most efficient system and was statistically superior to peristaltic pump.

Clinical study using a new phacoemulsification system with surgical intraocular pressure control

PURPOSE

To compare cumulative dissipated energy (CDE), aspiration fluid used, and aspiration time during phacoemulsification cataract extraction using 2 surgical configurations.

SETTING

Two clinical sites in the United States and 1 in Spain.

DESIGN

Prospective randomized clinical case series.

METHODS

For each patient, the first eye having surgery was randomized to the active-fluidics configuration (Centurion Vision System with Active Fluidics, 0.9 mm 45-degree Intrepid Balanced tip, and 0.9 mm Intrepid Ultra infusion sleeve) or the gravity-fluidics configuration (Infiniti Vision System with gravity fluidics, 0.9 mm 45-degree Mini-Flared Kelman tip, and 0.9 mm Ultra infusion sleeve). Second-eye surgery was completed within 14 days after first-eye surgery using the alternate configuration. The CDE, aspiration fluid used, and aspiration time were compared between configurations, and adverse events were summarized.

RESULTS

Patient demographics and cataract characteristics were similar between configurations (100 per group). The CDE was significantly lower with the active-fluidics configuration than with the gravity-fluidics configuration (mean ± standard error, 4.32 ± 0.28 percent-seconds) (P < .001). The active-fluidics configuration used significantly less aspiration fluid than the gravity-fluidics configuration (mean 46.56 ± 1.39 mL versus 52.68 ± 1.40 mL) (P < .001) and required significantly shorter aspiration time (mean 151.9 ± 4.1 seconds versus 167.6 ± 4.1 seconds) (P < .001). No serious ocular adverse events related to the study devices or device deficiencies were observed.

CONCLUSION

Significantly less CDE, aspiration fluid used, and aspiration time were observed with the active-fluidics configuration than with the gravity-fluidics configuration, showing improved surgical efficiency.

FINANCIAL DISCLOSURES

Drs. Solomon and Cionni are consultants to Alcon Research, Ltd., and received compensation for conduct of the study. Dr. Lorente received compensation for clinical work in the study. Mr. Fanney is an employee of Alcon Research, Ltd.

Comparative studies between longitudinal and torsional modes in phacoemulsification, using active fluidics technology along with the intrepid balanced tip

Purpose:

To compare and report the intra- and postoperative outcomes of phacoemulsification between longitudinal (LPKE) and torsional (TPKE) mode, using active fluidics along with the intrepid balanced tip.

Methods:

This single center prospective randomized comparative study comprised a total 108 consecutive eyes of 108 patients having senile cataract subdivided into nuclear opalescence (NO) grades II–IV according to the lens opacities classification system III (LOCS III). Cataracts of each grade were randomly assigned to two groups LPKE (n = 54) and TPKE (n = 54) mode, who were operated on by the same surgeon using same machine (Centurion^® Alcon Laboratories, Inc., USA) having features of both active fluidics and intrepid balanced tip. Pre-, intra-, and postoperative evaluations were done independently by a different author, who was masked to the surgical procedures. Patients were evaluated on the postoperative days (PODs) 1, 7, 15, and 28. Intraoperative outcome measures were cumulative dissipated energy (CDE) and ultrasound time (UST). Postoperative outcome measures were endothelial cell loss (ECL), central corneal thickness (CCT), and best-corrected visual acuity (BCVA).

Results:

Age, gender, and NO-grade distribution among two modes were comparable (P > 0.05). Difference of CDE and UST between modes were found to be significant (P < 0.001) in favor of TPKE with all NO-grades. TPKE mode performs better than LPKE mode with regard to ECL, CCT-change, and BCVA-change, although the differences were found to be insignificant (P > 0.05).

Conclusion:

When using active fluidics along with the intrepid balanced tip, TPKE mode appeared to be a more efficient mode of PKE with reduced mean UST and CDE across all NO-grades, as compared to LPKE mode. However, ECL, CCT-change, and BCVA-change were seemed to be comparable between the two modes.

Optimum on-time duty cycle for a transversal ultrasound machine

PURPOSE

To evaluate the optimum on-time setting for the most efficient removal of lens fragments using micropulse ultrasound (US) and Ellips FX transversal US in the Whitestar Signature Pro phacoemulsification machine.

SETTING

John A. Moran Eye Center Laboratories, University of Utah, Salt Lake City, Utah, USA.

DESIGN

Experimental study.

METHODS

Porcine lens nuclei were soaked in formalin for 2 hours and cut into 2.0 mm cubes. The US machine was used with a bent 0.9 mm phaco tip and a 30-degree bevel. The off time was set to 6 milliseconds (ms) and the on time varied from 4 to 10 ms in 1 ms increments. Efficiency (time for fragment removal) and chatter (number of times the fragment bounced from the tip) were measured.

RESULTS

A linear incremental increase in efficiency was observed between 4 ms and 6 ms. The most statistically significant efficiency was achieved with an on time of 6 ms. On times shorter than 6 ms were significantly less efficient (P = .05). Greater on times (7 to 10 ms) did not result in a significant difference in efficiency (P = .72), but did appear to have more chatter events when comparing on-time settings of 7 to 10 ms with 4 to 6 ms (P = .02).

CONCLUSIONS

With micropulse transversal US, 6 ms of on time was as efficient as longer on times. To maximize phacoemulsification efficiency and minimize chatter events, an on time of 6 ms is recommended.

Impact of virtual reality simulation on learning barriers of phacoemulsification perceived by residents

Objective

To identify residents’ perceived barriers to learning phacoemulsification surgical procedures and to evaluate whether virtual reality simulation training changed these perceptions.

Design

The ophthalmology residents undertook a simulation phacoemulsification course and proficiency assessment on the Eyesi system using the previously validated training modules of intracapsular navigation, anti-tremor, capsulorrhexis, and cracking/chopping. A cross-sectional, multicenter survey on the perceived difficulties in performing phacoemulsification tasks on patients, based on the validated International Council of Ophthalmology’s Ophthalmology Surgical Competency Assessment Rubric (ICO-OSCAR), using a 5-point Likert scale (1 = least and 5 = most difficulty), was conducted among residents with or without prior simulation training. Mann–Whitney U tests were carried out to compare the mean scores, and multivariate regression analyses were performed to evaluate the association of lower scores with the following potential predictors: 1) higher level trainee, 2) can complete phacoemulsification most of the time (>90%) without supervisor’s intervention, and 3) prior simulation training.

Setting

The study was conducted in ophthalmology residency training programs in five regional hospitals in Hong Kong.

Results

Of the 22 residents, 19 responded (86.3%), of which 13 (68.4%) had completed simulation training. Nucleus cracking/chopping was ranked highest in difficulty by all respondents followed by capsulorrhexis completion and nucleus rotation/manipulation. Respondents with prior simulation training had significantly lower difficulty scores on these three tasks (nucleus cracking/chopping 3.85 vs 4.75, P = 0.03; capsulorrhexis completion 3.31 vs 4.40, P = 0.02; and nucleus rotation/manipulation 3.00 vs 4.75, P = 0.01). In multivariate analyses, simulation training was significantly associated with lower difficulty scores on these three tasks.

Conclusion

Residents who had completed Eyesi simulation training had higher confidence in performing the most difficult tasks perceived during phacoemulsification.

Outcomes study between femtosecond laser-assisted cataract surgery and conventional phacoemulsification surgery using an active fluidics system

Purpose

The purpose of this study was to compare intraoperative parameters between femtosecond laser-assisted cataract surgery (FLACS) and conventional phacoemulsification using Centurion^® Vision System with Active Fluidics.

Setting

This study was performed at Brasília Ophthalmologic Hospital, Brasília, Federal District, Brazil.

Patients and methods

This was a prospective randomized comparative study. Patients with the diagnosis of cataract and surgical extraction programmed were divided into two groups: conventional phacoemulsification and FLACS. Intraoperative data were collected and submitted for statistical analysis.

Results

A total of 400 eyes were enrolled, 200 in each group. There were no surgical complications. Groups were statistically equivalent in age and nucleus density. Cumulative dissipated energy and torsional time were significantly reduced in the FLACS group. Conventional surgery had less fluid usage, total case time and aspiration (ASP) time.

Conclusion

FLACS with Active Fluidics System can reduce the ultrasound energy use during cataract surgery, in spite of increasing case time, fluid usage and ASP time.

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.

COMPARISON OF RECENTLY USED PHACOEMULSIFICATION SYSTEMS USING A HEALTH TECHNOLOGY ASSESSMENT METHOD

Objectives: To compare the recently used phacoemulsification systems using a health technology assessment (HTA) model.

Methods: A self-administered questionnaire, which included questions to gauge on the opinions of the recently used phacoemulsification systems, was distributed to the chief cataract surgeons in the departments of ophthalmology of eighteen tertiary hospitals in Shanghai, China. A series of senile cataract patients undergoing phacoemulsification surgery were enrolled in the study. The surgical results and the average costs related to their surgeries were all recorded and compared for the recently used phacoemulsification systems.

Results: The four phacoemulsification systems currently used in Shanghai are the Infiniti Vision, Centurion Vision, WhiteStar Signature, and Stellaris Vision Enhancement systems. All of the doctors confirmed that the systems they used would help cataract patients recover vision. A total of 150 cataract patients who underwent phacoemulsification surgery were enrolled in the present study. A significant difference was found among the four groups in cumulative dissipated energy, with the lowest value found in the Centurion group. No serious complications were observed and a positive trend in visual acuity was found in all four groups after cataract surgery. The highest total cost of surgery was associated with procedures conducted using the Centurion Vision system, and significant differences between systems were mainly because of the cost of the consumables used in the different surgeries.

Conclusions: This HTA comparison of four recently used phacoemulsification systems found that each of system offers a satisfactory vision recovery outcome, but differs in surgical efficacy and costs.

Effect of fluidics on corneal endothelial cell density, central corneal thickness, and central macular thickness after phacoemulsification with torsional ultrasound

Aim:

To study the relative effects of high and low fluidic parameters on endothelial cell density (ECD), central corneal thickness (CCT), and central macular thickness (CMT) after phacoemulsification with torsional ultrasound.

Settings and Design:

Prospective, randomized clinical trial based on a tertiary eye hospital.

Subjects and Methods:

The study included 65 patients in each group. Patients were randomized to either the high or the low flow group using a computerized random number table. The study was patient and examiner masked. All patients underwent phacoemulsification with torsional ultrasound. Visual acuity, ECD, CCT, and CMT were measured for all patients preoperatively at 2 weeks and 6 weeks postoperatively.

Statistical Analysis Used:

The Shapiro–Wilks test was used to assess the normality of the data. Mann–Whitney U-test with the P value set at 0.05 was used to compare the two groups.

Results:

Cumulative dissipated energy was significantly higher in the low flow group (16.44 ± 9.07 vs. 11.74 ± 6.68; P = 0.002). No statistically significant difference was noted between the two groups in the ECD, CCT, CMT, or corrected distance visual acuity at the end of 6 weeks.

Conclusions:

No significant difference was noted in the postoperative outcome between high and low flow groups. Parameters can be modified to suit the surgeon's preference, as both high and low flow parameters were found to have comparable postoperative outcomes.

Comparison of 45-degree Kelman and 45-degree balanced phaco tip designs in torsional microcoaxial phacoemulsification

AIM

To compare the intraoperative performance and postoperative outcome after microcoaxial torsional phacoemulsification using either a Kelman or balanced phaco tip.

METHODS

Cataracts were treated using 2.2 mm microcoaxial torsional phacoemulsification using either a 45-degree mini-flared Kelman(®) or a 45-degree Intrepid(®) Balanced phaco tip. Intraoperative measurements included total ultrasound (US) time, cumulative dissipated energy (CDE), torsional US time, and balanced salt solution (BSS) use. The central endothelial cell density (ECD) and central corneal thickness (CCT) were evaluated preoperatively and postoperatively 1, 7, and 30d after surgery using noncontact specular microscopy.

RESULTS

The 116 enrolled eyes (116 patients) were divided equally between the Kelman and balanced tip groups. Intraoperative measurements showed significantly less total US time, torsional US time, CDE, and BSS use in the balanced group than in Kelman group (P<0.05). The total US time, torsional US time, CDE, and BSS use were 17.45±14.53s, 16.63±13.97s, 6.38±5.26, and 48.21±17.21 mL in the Kelman group and 11.39 ± 9.60s, 10.90 ± 9.25s, 4.04 ± 3.42, and 41.36 ± 12.70 mL in the balanced group, respectively.

CONCLUSION

Torsional phacoemulsification performed with a balanced tip provided more effective lens removal with less total US time, torsional time, CDE, and BSS use, as well as similar changes in ECD with a Kelman tip in all cataract grades. This special designed phaco tip for torsional phacoemulsification provides an alternative phaco tip for many surgeons' preference with straight phaco tip.

Transverse vs torsional ultrasound: prospective randomized contralaterally controlled study comparing two phacoemulsification-system handpieces

PURPOSE

To compare surgical efficiency and multiple early clinical outcome variables in eyes undergoing phacoemulsification using either transversal or torsional ultrasound systems.

SETTING

Assil Eye Institute, Beverly Hills, CA, USA.

DESIGN

Prospective, randomized, clinician-masked, contralaterally controlled single-center evaluation.

PATIENTS AND METHODS

Patients seeking cataract removal in both eyes with implantation of multifocal intraocular lenses were randomly assigned to one of two treatment rooms for phacoemulsification with either a transverse ultrasound system or torsional handpiece system. The contralateral eye was treated at a later date with the alternate device. A total of 54 eyes of 27 patients having similar degrees of cataract, astigmatism, and visual potential were included. All operative data were collected for analysis, and patients were followed for 3 months after surgery.

RESULTS

Similar visual acuity was reported at all postoperative visits between the two groups. Mean phacoemulsification time and total power required were both significantly lower with the transverse system than with the torsional technique (P<0.05 for both). Similarly, mean total balanced salt solution used was significantly less with the transverse system vs torsional (P<0.05). Postoperative safety demonstrated significantly lower endothelial cell loss at 1 day and 1 month (P<0.05) with transverse vs torsional. Macular swelling was less at 1 week, 1 month, and 3 months with transverse vs torsional, although the difference did not achieve significance (P=0.1) at any single time point. Clinically detectable corneal edema was reported less frequently at all postoperative time points with the transverse system.

CONCLUSION

The transverse ultrasound system was found to be possibly associated with less balanced salt-solution use, less phacoemulsification time, and less power required than the torsional phaco system. Postoperative data suggested that improved phaco efficiency may translate to a better overall safety profile for the patient.

Effect of torsional mode phacoemulsification on cornea in eyes with/without pseudoexfoliation

AIM

To evaluate the effect of torsional mode phacoemulsification on central corneal thickness, corneal endothelial cell density, and morphology in eyes with/without pseudoexfoliation (PEX) syndrome.

METHODS

Fourty-two consecutive patients with and 42 patients without PEX as a control group scheduled for cataract surgery was studied. Phacoemulsification, using OZiL IP system, was performed with quick chop technique. Using noncontact specular microscopy, the central endothelial cell density (ECD), coefficient of variation, percentage of hexagonal cells, and the central corneal thickness (CCT) were evaluated preoperatively and postoperatively at 1, 7 and 30d.

RESULTS

The ECD in PEX syndrome was statistically significantly lower than that in the control group preoperatively and postoperatively (P≤0.001). Percentage change in ECD was statistically significantly higher in PEX than that in control group after surgery follow up (P≤0.04). There was no statistically significant difference between both groups comparing percentage of hexagonal cells and coefficient of variation in the cell size before and after the surgery. At 1 and 7d after surgery, percentage change in CCT was statistically significantly higher in PEX group than that in the control group (P≤0.041).

CONCLUSION

Although torsional mode phacoemulsification and intraocular lens (IOL) implantation provided a safe and favorable surgical outcome in patients with/without PEX, torsional phacoemulsification led to significantly higher ECD loss in the PEX group than that in the control group during the whole follow up period. In addition, more corneal swelling in the PEX group than that in the control group during the early postoperative period has indicated that the corneal endothelium, in presence of PEX endotheliopathy, seems to be more susceptible to the effects of phacoemulsification surgery in eyes with PEX. The increased risk of anterior chamber manipulations in patients with PEX should be taken into account for an increased risk of bullous keratopathy.

The Impact of Reused Phaco Tip on Outcomes of Phacoemulsification Surgery

PURPOSE

To evaluate the impact of reused phaco tip on intraoperative performance and postoperative outcomes after 2.2 mm micro-coaxial torsional and transversal phacoemulsification.

MATERIAL AND METHODS

This prospective randomized study enrolled 136 eyes of 136 cataract patients; 68 eyes in torsional group (34 eyes with single use tip, 34 eyes with reused tip) and 68 eyes in transversal group (34 eyes with single use tip, 34 eyes with reused tip). Intraoperative measurements were total ultrasound (U/S) time, torsional U/S time, cumulative dissipated energy (CDE), estimated fluid use (EFU) in the torsional group and total phacoemulsification time (TPT), and effective phacoemulsification time (EPT) in transversal phacoemulsification. The central endothelial cell density (ECD) and the central corneal thickness (CCT) were evaluated preoperatively and postoperatively at 1 and 30 days using noncontact specular microscopy.

RESULTS

Intraoperative measurements in torsional phacoemulsification showed significant increase in total U/S time (p = 0.01), torsional U/S time (p = 0.01), and CDE (p = 0.01) with the reused tip. The EFU was similar in both tip groups (p = 0.36). The total U/S time, torsional U/S time, and CDE in torsional group were significantly increased with the reused tip for grade III (p = 0.03 for all parameters) and grade IV cataracts (p = 0.005 for torsional U/S time and CDE; p = 0.006 for total U/S time). Intraoperative measurements in transversal phacoemulsification showed no differences in TPT and EPT between tip groups (p > 0.05). The change in ECD and CCT in torsional and transversal phacoemulsification groups were similar in both tip groups (p > 0.05).

CONCLUSIONS

This study showed that sharpness of phaco tip edge increases the efficiency of torsional phacoemulsification for hard cataracts. This result does not mean that reused phaco tip may be used in soft and medium cataracts. As the timing of tip's change is a user-dependent procedure, a new single phaco tip should be used in each case if possible.

Comparison of corneal endothelial changes following phacoemulsification with transversal and torsional phacoemulsification machines

AIM

To compare and evaluate the phacoemulsification parameters and postoperative endothelial cell changes of two different phacoemulsification machines, each with different modes, but also to assess the relationship between postoperative endothelial cell loss and the phacoemulsification parameters, as well as the other factors in both groups.

METHODS

This prospective observational study was comprised of consecutive eligible cataract patients operated with phacoemulsification technique performed by the same surgeon using either a WHITESTAR Signature Ellips FX (transversal, group 1) or Infiniti OZil IP (torsional, group 2) machine.

RESULTS

The study included 86 patients. Baseline characteristics in the groups were similar. The median nuclear sclerosis grade was 3 (2-4) in the first group and 2 (2-4) in the second group (P=0.265). Both groups had similar phacoemulsification needle times (group 1: 60.63±36 s; group 2: 55.98±30 s; P=0.789). The percentage of endothelial cell loss 30d after surgery ranged from 3% to 15% with a median of 7% in group 1, and from 2% to 13% with a median of 6% in group 2; however, there was no statistically significant difference between the groups (P=0.407). Hexagonality (P=0.794) and the coefficient of variation (CV; P=0.142) did not differ significantly between the groups before and 30d after surgery. A significant positive correlation was found between the endothelial cell loss and nuclear sclerosis grade (group 1: P<0.001; group 2: P<0.001) and between the endothelial cell loss and average phacoemulsification power (group 1: P=0.007; group 2: P=0.008).

CONCLUSION

Both of these machines were efficient, with similar endothelial cell loss. This endothelial cell loss was related to the increased nuclear sclerosis grade and increased phacoemulsification power.

Comparative analysis of corneal morphological changes after transversal and torsional phacoemulsification through 2.2 mm corneal incision

Purpose

This paper compares and evaluates the corneal morphological changes occurring after cataract surgery through a 2.2 mm corneal incision. We use two platforms for comparison and evaluation, transversal and torsional phacoemulsification.

Patients and methods

This study includes 139 consecutive cataractous eyes (nuclear color 2–4, according to the Lens Opacities Classification System III [LOCSIII]) of 82 patients undergoing cataract surgery through a 2.2 mm corneal incision. Two different phacoemulsification platforms were used and assigned randomly: we used the WhiteStar Signature^® system with the Ellips™ FX transversal continuous ultrasound (US) mode for group I (mean age: 65.33 ± 6.97 years), and we used the Infiniti^® system with the OZil^® Intelligent Phaco (IP) torsional US mode for group II (mean age: 64.02 ± 7.55 years). The corneal endothelium and pachymetry were evaluated preoperatively and at 1 month postoperatively. Incision size changes were also evaluated.

Results

All surgeries were uneventful. Before intraocular lens implantation, the mean incision size was 2.24 ± 0.06 mm in both groups (P = 0.75). In terms of corneal endothelial cell density, neither preoperative (I vs II: 2304.1 ± 122.5 cell/mm² vs 2315.6 ± 83.1 cell/mm², P = 0.80) nor postoperative (I vs II: 2264.1 ± 124.3 cell/mm² vs 2270.3 ± 89.9 cell/mm², P = 0.98) differences between the groups were statistically significant. The mean endothelial cell density loss was 1.7% ± 1.6% and 2.0% ± 1.4% in groups I and II, respectively. Furthermore, no significant differences between groups I and II were found preoperatively (P = 0.40) and postoperatively (P = 0.68) in central pachymetry. With surgery, the mean increase in central pachymetry was 28.1 ± 23.6 μm and 24.0 ± 24.0 μm in groups I and II, respectively (P = 0.1).

Conclusion

Ellips™ FX transversal and OZil^® IP torsional phacoemulsification modes are safe for performing cataract surgery, inducing minimal corneal thickness and endothelial changes.