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Journal Article•DOI•

Torsional mode versus conventional ultrasound mode phacoemulsification: Randomized comparative clinical study

Yizhi Liu1, M. Zeng1, Xialin Liu1, Lixia Luo1, Zhaohui Yuan1, Yuanlin Xia1, Yangfa Zeng1 •
Sun Yat-sen University1
01 Feb 2007-Journal of Cataract and Refractive Surgery (Elsevier)-Vol. 33, Iss: 2, pp 287-292
TL;DR: The torsional mode may provide more effective lens removal with a lower level of phacoemulsification time and energy.
Abstract: Purpose To compare the intraoperative and short-term postoperative outcomes of cataract surgery performed with torsional mode and conventional ultrasound mode using the Infiniti Vision System (Alcon Laboratories). Setting Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, Guangzhou, China. Methods In this randomized comparative study, 525 eyes were assigned to phacoemulsification by torsional mode or conventional ultrasound (US) mode. The surgery was performed by an experienced surgeon, and the outcomes were evaluated by an examiner who was masked to treatment assignments. Primary outcome measures were US time (UST), cumulative dissipated energy (CDE), and surgical complications. Patients were seen 1, 7, and 30 days after surgery. Postoperative outcome measures were the final best corrected visual acuity (BCVA) and the change in corneal clarity, central corneal thickness (CCT), and endothelial cell count. Results The US group had 262 eyes and the torsional group, 263 eyes. All patients completed the follow-up visits. In the eyes with nucleus density grades of 1, 2, 3, and 4, the mean UST was 10.25 seconds ± 7.4 (SD), 25.14 ± 5.5 seconds, 36.45 ± 8.3 seconds, and 61.44 ± 17.8, respectively, in the US group and 8.32 ± 6.8 seconds, 18.45 ± 7.2 seconds, 29.48 ± 12.4 seconds, and 48.39 ± 20.3 seconds, respectively, in the torsional group ( P P P P >.01). At 1 day and 7 days, the mean CCT was 625 ± 80 μm and 568 ± 37 μm, respectively, in the US group and 601 ± 35 μm and 559 ± 40 μm, respectively, in the torsional group ( P P >.01). At 7 days and 30 days, the mean central corneal endothelial cell count was 2135 ± 858 cells/mm 2 and 2084 ± 527 cells/mm 2 , respectively, in the US group and 2004 ± 656 cells/mm 2 and 1953 ± 615 cells/mm 2 , respectively, in the torsional group ( P Conclusion The torsional mode may provide more effective lens removal with a lower level of phacoemulsification time and energy.
Citations
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Journal Article•DOI•
Torsional ultrasound modality for hard nucleus phacoemulsification cataract extraction

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M. Zeng1, Xing Liu, Yizhi Liu, Y Xia, Lixia Luo, Z Yuan, Y Zeng •
Sun Yat-sen University1
01 Aug 2008-British Journal of Ophthalmology
TL;DR: Torsional combined with ultrasound power or high fixed torsional amplitude can yield more effective hard nucleus phacoemulsification than conventional ultrasound modality.
Abstract: Aim: To evaluate the efficacy and safety of phacoemulsification using torsional modality with different parameter settings for hard nucleus cataract extraction. Design: A prospective, randomised clinical study. Methods: A clinical practice study conducted at the Cataract Service, Zhongshan Ophthalmic Center, Sun-Yat-Sen University, and Guangzhou. One eye each from 198 consecutive patients with cataract density grade IV according to the Emery–Little system classification system, requiring phacoemulsification and intraocular lens implantation, was included. Eyes were randomly assigned to the Linear Torsional combined with Ultrasound power group (Linear Tor+US group, n = 66), 100% Fixed Torsional group (Fixed Tor group, n = 65) and conventional Ultrasound burst group (US group, n = 67). All surgeries were performed by a single experienced surgeon and outcomes evaluated by another surgeon masked to treatment. Intraoperative parameters were Ultrasound Time (UST), Cumulative Dissipated Energy (CDE) and surgical complications. Patients were examined on post-op days 1, 7 and 30. Postoperative outcomes were final best corrected visual acuity (BCVA), average central and incisional corneal thickness and central endothelial cell counts. Results: The mean UST was lower in the Fixed Tor group than in the US group and in the Lin US+Tor group (p⩽0.0001). The mean CDE was lower in the Lin Tor+US group and in the Fixed Tor group than in the US group (p⩽0.0001). Comparing with the two Tor group, the US group had a lower average BCVA on post-op 1, 7 (p⩽0.0001) and 30 (p>0.01), greater average central corneal and incisional thickness on days 1, 7 (p⩽0.0001) and 30 (p>0.01), and higher average corneal endothelial cell losses on day 7 and 30 days (p⩽0.0001). Conclusions: Torsional combined with ultrasound power or high fixed torsional amplitude can yield more effective hard nucleus phacoemulsification than conventional ultrasound modality.

71 citations

Cites background from "Torsional mode versus conventional ..."

  • ...Comparing with the jackhammer motion in conventional phaco, the improved OZil Torsional oscillation sheers the lens material with virtually no repulsion, thereby dramatically reduced phaco energy required for lens removal without compromising efficiency.(5) Torsional works at a lower frequency of 32 kHz than the 40,45 kHz in conventional phaco and theoretically reduces efficiency in lens removal, especially with hard nucleus....

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Journal Article•DOI•
Heat production: Longitudinal versus torsional phacoemulsification.

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Young Keun Han1, Kevin M. Miller1•
University of California, Los Angeles1
01 Oct 2009-Journal of Cataract and Refractive Surgery
TL;DR: Lower operating temperatures indicate lower heat generation within the same volume of fluid, and this may provide additional thermal protection during cataract surgery.
Abstract: Purpose To compare the heat production of longitudinal versus torsional phacoemulsification under strict laboratory test conditions. Setting Department of Ophthalmology, David Geffen School of Medicine at UCLA, and Jules Stein Eye Institute, Los Angeles, California, USA. Methods Two Infiniti phacoemulsification handpieces were inserted into silicone test chambers filled with a balanced salt solution and imaged serially using a thermal camera. Incision compression was simulated by suspending 25.3 g weights from the silicone chambers. To simulate occlusion of the phacoemulsification tip, the aspiration line was clamped. Peak temperatures were measured 0, 10, 30, 60, and 120 seconds after the commencement of continuous ultrasound power. The 2 handpieces, operating exclusively in longitudinal or torsional modes, were compared 3 ways: (1) using the same power displayed on the instrument console, (2) using identical stroke lengths, and (3) using the same applied energy, a product of stroke length and frequency. Results For all 3 comparisons, torsional phacoemulsification resulted in lower temperatures at each time point. At the same displayed power setting, the scenario most familiar to cataract surgeons, longitudinal phacoemulsification elevated temperatures up to 41.5°C more than torsional phacoemulsification. Conclusions Torsional phacoemulsification generated less heat than longitudinal phacoemulsification in all 3 comparison tests. Lower operating temperatures indicate lower heat generation within the same volume of fluid, and this may provide additional thermal protection during cataract surgery.

63 citations

Cites background from "Torsional mode versus conventional ..."

  • ...Torsional phacoemulsification has several advantages over longitudinal phacoemulsification, including increased followability, decreased energy use, shorter surgical time, and less endothelial damage in cataract surgery.(6,7) Mechanically, many of the differences can be explained by the side-to-sidemotion of the torsional...

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  • ...phacoemulsification tip with reduced repulsion of lens fragments.(6,7) In an effort to repeat the success of a previous thermal study inwhichwe compareddifferent longitudinal platforms,(5)wemeasured thermaldifferences between longitudinal and torsional modalities....

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Journal Article•DOI•
Comparison of torsional and longitudinal modes using phacoemulsification parameters

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Marek Rękas, Robert Montés-Micó, Karolina Krix-Jachym, Adam Kluś, Andrzej Stankiewicz, Teresa Ferrer-Blasco 
01 Oct 2009-Journal of Cataract and Refractive Surgery
TL;DR: Torsional phacoemulsification was more effective than longitudinal phacoEmulsification in the amount of applied fluid and the quantity of US energy expended and with the torsional method, it was possible to maintain a constant ratio of amount of fluid flow to quantity ofUS energy used, regardless of nucleus density.
Abstract: Purpose To compare phacoemulsification parameters of torsional and longitudinal ultrasound modes. Setting Ophthalmology Department, Military Health Service Institute, Warsaw, Poland. Methods This prospective study evaluated eyes 1, 7, and 30 days after phacoemulsification with an Infiniti Vision System using the torsional or longitudinal ultrasound (US) mode. Cataract classification was according to the Lens Opacities Classification System II. Nucleus fragmentation was by the phaco-chop and quick-chop methods. Primary outcome measures were phaco time, mean phaco power, mean torsional amplitude, and aspiration time. Total energy, defined as cumulative dissipated energy (CDE) × aspiration time, and the effective coefficient, defined as aspiration time/phaco time, were also calculated. Results Four hundred eyes were evaluated. The CDE was statistically significantly lower in the torsional mode for nucleus grades I, II, and III (P .05). Aspiration time was statistically significantly shorter in the torsional mode than in the longitudinal mode for nucleus grades III and IV (P Conclusions Torsional phacoemulsification was more effective than longitudinal phacoemulsification in the amount of applied fluid and the quantity of US energy expended. With the torsional method, it was possible to maintain a constant ratio of amount of fluid flow to quantity of US energy used, regardless of nucleus density.

63 citations

Cites background or methods or result from "Torsional mode versus conventional ..."

  • ...which is manipulation in the anterior chamber with an auxiliary instrument, is used primarily for chopping and breaking the lens nucleus, particularly in the phaco-chop technique, and this appears to have only a minor negative effect on endothelial cells.(7) Ultrasound and fluid dynamic energy, on the other hand, have a significantly more pronounced negative effect on ocular structures....

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  • ...In the course of phacoemulsification, energy is delivered to the eye in 3 forms: mechanical, US, and fluid dynamics.(7) Mechanical energy, the source of...

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  • ...Liu et al.7 also observed a continuous increase in CDE with increasing nuclear density....

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  • ...Liu et al.(7) also observed a continuous increase in CDE with increasing nuclear density....

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  • ...The amount of US energy supplied to the eye depends on surgeon experience and the nucleus density of the lens to be removed.(7,11,16,22) In our study, as nucleus density increased, the differences in CDE values between the torsional mode and longitudinal mode Table 5....

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Journal Article•DOI•
Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification

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Anna Reuschel1, Holger Bogatsch1, Thomas Barth1, Renate Wiedemann1•
Leipzig University1
01 Nov 2010-Journal of Cataract and Refractive Surgery
TL;DR: The torsional mode was as safe as the longitudinal mode in phacoemulsification for age‐related cataract as well as conventional longitudinal mode, according to Conference on Harmonisation‐E9 Guidelines.
Abstract: Purpose To compare the intraoperative and postoperative outcomes of conventional longitudinal phacoemulsification and torsional phacoemulsification. Setting Department of Ophthalmology, University of Leipzig, Germany. Design Randomized single-center clinical trial. Methods Eyes with senile cataract were randomized to have phacoemulsification using the Infiniti Vision System and the torsional mode (OZil) or conventional longitudinal mode. Primary outcomes were corrected distance visual acuity (CDVA) and central endothelial cell density (ECD), calculated according to the Conference on Harmonisation-E9 Guidelines in which missing values were substituted by the median in each group (primary analysis) and the loss was then calculated using actual data (secondary analysis). Secondary outcomes were ultrasound (US) time, cumulative dissipated energy (CDE), and percentage total equivalent power in position 3. Postoperative follow-up was at 3 months. Results The mean preoperative CDVA was 0.41 logMAR in the torsional group and 0.38 logMAR in the longitudinal group, improving to 0.07 logMAR postoperatively in both groups. The mean ECD loss was 7.2% ± 4.6% in the torsional group (72 patients) and 7.1% ± 4.4% in the longitudinal group (76 patients), with no statistically significant differences in the primary analysis (P = .342) or secondary analysis (P = .906). The mean US time, CDE, and percentage total equivalent power in position 3 were statistically significantly lower in the torsional group (98 patients) than in the longitudinal group (94 patients) (P Conclusion The torsional mode was as safe as the longitudinal mode in phacoemulsification for age-related cataract. Financial Disclosure No author has a financial or proprietary interest in any material or method mentioned.

59 citations

Cites background or methods from "Torsional mode versus conventional ..."

  • ...This could explain the higher endothelial cell loss because specular microscopy should be performed when the loss has stabilized (at least 3 months postoperatively).22,33 Another difference is that Liu et al. used a different method of cataract removal....

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  • ...Liu et al.(18) report the same for CDE and US time and Rekas et al....

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  • ...Liu et al.18 report the same for CDE and US time and Rekas et al.,45 for CDE in the eyes with the same nucleus density....

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  • ...This result is comparable to those in other studies.22,23 Liu et al.18 report no difference in CDVA between the 2 methods 1 month after phacoemulsification....

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  • ...4 is for standardization of the torsional tip to allow comparison with conventional longitudinal phacoemulsification.(18) The percentage total equivalent power in position 3 is the percentage of dissipated energy at unit time in position 3 and is calculated as follows: CDE/US time....

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Journal Article•DOI•
Relationship between endothelial cell loss and microcoaxial phacoemulsification parameters in noncomplicated cataract surgery

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Mohamed Ae Soliman Mahdy1, Mohamed Zakaria Eid, Mahmoud Abdel-Badei Mohammed, Amr Hafez, Jagdish Bhatia •
Al-Azhar University1
29 Mar 2012-Clinical Ophthalmology
TL;DR: Microcoaxial phacoemulsification was efficient in removing noncomplicated cataract patients with different grades of nuclear hardness; however a statistically significant endothelial cell loss was noted, especially with increased nuclear hardness.
Abstract: Purpose: To assess the relationship between postoperative endothelial cell loss and microcoaxial phaco parameters using Ozil IP (Alcon Laboratories, Inc, Fort Worth, TX) in noncomplicated cataract surgery. Methods: In this prospective observational study, 120 consecutive cases of cataract patients with different grades of nuclear hardness underwent microcoaxial phacoemulsification through a 2.2-mm clear corneal incision. An Alcon Infinity Vision System with Ozil IP (Alcon Laboratories) was used with an Ozil torsional handpiece and a Kelman-style 45° phacoemulsification tip. Patients underwent preoperative and postoperative central endothelial cell counts. Results: The study included 120 cases of age-related cataract whose mean age (standard deviation [SD]) was 59.68 years (9.47). There was a highly statistically significant endothelial cell loss (P , 0.001). The endothelial cell loss ranged 11–1149 cells/mm 2 with a median (interquartile range) of 386 cells/mm 2 (184.5–686 cells/mm 2 ). The percentage of postoperative ECLoss% ranged from 0.48% to 47.8% with a median (interquartile range) of 15.4% (7.2% to 26.8%). A significant positive correlation was found between the ECLoss% and different phaco parameters. The Spearman’s rank-order correlation coefficient values, rho, (ρ) were as follows: CDE (ρ = 0.425), aspiration time (ρ = 0.176), and volume (ρ = 0.278). Also, ECLoss% was significantly correlated with the grade of nuclear opalescence (Kendall’s tau τ = 0.42). Conclusion: Microcoaxial phacoemulsification was efficient in removing noncomplicated cataracts; however a statistically significant endothelial cell loss was noted, especially with increased nuclear hardness. This endothelial cell loss was mostly related to the increased cumulative dissipated energy (CDE), aspiration time, and volume of balanced salt solution used.

58 citations

Cites background from "Torsional mode versus conventional ..."

  • ...Torsional US has a lower resonant frequency and slower needle movement than conventional US, which allows for optimized cutting efficiency with reduced heat generation.(2,4,5) Torsional US at different vacuum levels, like conventional US, leads to differences in parameters such as phaco time, US efficiency, and endothelial cell changes....

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  • ...Clinical Ophthalmology 2012:6 Torsional ultrasound (US) using a torsional handpiece that produces side-to-side rotary oscillations has been recently introduced.(2,3) Torsional US has a lower resonant frequency and slower needle movement than conventional US, which allows for optimized cutting efficiency with reduced heat generation....

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References
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Journal Article•DOI•
The Lens Opacities Classification System III

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Leo T. Chylack1, John K. Wolfe, D.M. Singer, M. C. Leske, Mark A. Bullimore, Ian Bailey, Judith Friend, D. Mccarthy, Suh Yuh Wu •
Brigham and Women's Hospital1
01 Jun 1993-Archives of Ophthalmology
TL;DR: The LOCS III is an improved LOCS system for grading slit-lamp and retroillumination images of age-related cataract and contains an expanded set of standards that were selected from the Longitudinal Study of Cataract slide library.
Abstract: • Objective. —To develop the Lens Opacities Classification System III (LOCS III) to overcome the limitations inherent in lens classification using LOCS II. These limitations include unequal intervals between standards, only one standard for color grading, use of integer grading, and wide 95% tolerance limits. Design and Results. —The LOCS III contains an expanded set of standards that were selected from the Longitudinal Study of Cataract slide library at the Center for Clinical Cataract Research, Boston, Mass. It consists of six slitlamp images for grading nuclear color (NC) and nuclear opalescence (NO), five retroillumination images for grading cortical cataract (C), and five retroillumination images for grading posterior subcapsular (P) cataract. Cataract severity is graded on a decimal scale, and the standards have regularly spaced intervals on a decimal scale. The 95% tolerance limits are reduced from 2.0 for each class with LOCS II to 0.7 for nuclear opalescence, 0.7 for nuclear color, 0.5 for cortical cataract, and 1.0 for posterior subcapsular cataract with the LOCS III, with excellent interobserver agreement. Conclusion. —The LOCS III is an improved LOCS system for grading slit-lamp and retroillumination images of age-related cataract.

2,540 citations

Journal Article•DOI•
Lens Opacities Classification System II (LOCS II)

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Leo T. Chylack1, M. Cristina Leske, D. Mccarthy, Patricia M. Khu, Toyohiko Kashiwagi, Robert D. Sperduto •
Harvard University1
01 Jul 1989-Archives of Ophthalmology
TL;DR: Very good interobserver reproducibility of the clinical gradings at the slit lamp, excellent intraobserver reproducecibility, very good to excellent interob server reproducible of photographic gradings, and good agreement between clinical and photographic grading are obtained.
Abstract: The Lens Opacities Classification System, version II (LOCS II), uses a set of colored slit-lamp and retroillumination transparencies to grade different degrees of nuclear, cortical, and subcapsular cataract. The system uses four nuclear standards for grading nuclear opalescence and color, five cortical standards, and four subcapsular standards. The LOCS II can be used to grade patients' cataracts at the slit lamp or to grade slit-lamp and retroillumination photographs; it is easy to learn and can be applied consistently by different observers. We obtained very good interobserver reproducibility of the clinical gradings at the slit lamp, excellent intraobserver reproducibility, very good to excellent interobserver reproducibility of photographic gradings, and good agreement between clinical and photographic gradings. The LOCS II is potentially useful for both cross-sectional and longitudinal studies of cataract.

559 citations

"Torsional mode versus conventional ..." refers methods in this paper

  • ...These included lens nucleus density grading according to the Lens Opacities Classification System II (LOCS II).(7) The eyes were then randomly assigned to conventional US mode or torsional mode using ballots drawn from a sealed envelope just before surgery....

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Journal Article•DOI•
Phaco-Emulsification and Aspiration: A New Technique of Cataract Removal: A Preliminary Report.

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Charles D. Kelman1•
Manhattan Eye, Ear and Throat Hospital1
01 Jul 1967-American Journal of Ophthalmology

467 citations

Journal Article•DOI•
Phaco-Emulsification and Aspiration: A Progress Report

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Charles D. Kelman
01 Jul 1967-American Journal of Ophthalmology

169 citations

Journal Article•DOI•
Risk factors for endothelial cell loss after phacoemulsification surgery by a junior resident.

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Paul D. O’Brien1, Patricia Fitzpatrick2, Dara J. Kilmartin1, Stephen Beatty•
Royal Victoria Eye and Ear Hospital1, University College Dublin2
01 Apr 2004-Journal of Cataract and Refractive Surgery
TL;DR: Advice to junior surgeons to choose cases with less dense cataracts as this will help reduce the absolute phaco time and thus minimize endothelial cell loss is supported.
Abstract: Purpose: To assess the risk factors for endothelial cell loss after phacoemulsification cataract surgery performed by a junior resident. Setting: Ophthalmic teaching hospital, Dublin, Ireland. Methods: This prospective study included 40 eyes having divide-and-conquer phacoemulsification cataract surgery by a junior resident under the supervision of an experienced surgeon. Nine variables were examined to assess the risk for corneal endothelial cell loss postoperatively. Results: The mean overall endothelial cell loss was 11.6%. Longer surgery time, longer absolute and effective phaco time, higher mean ultrasound power, and higher cataract density were significantly associated with endothelial cell loss on univariate analysis. Multivariate analysis identified a grade 3 nucleus (severely dense) and long absolute phaco time as independent predictors for endothelial cell loss, with longer absolute phaco time the stronger predictor. Conclusions: Divide-and-conquer phacoemulsification cataract surgery was a safe technique in the hands of an ophthalmic trainee. This study supports advice to junior surgeons to choose cases with less dense cataracts as this will help reduce the absolute phaco time and thus minimize endothelial cell loss.

127 citations

"Torsional mode versus conventional ..." refers background in this paper

  • ...the risk for endothelial cell loss and tissue damage.(4,5) Reducing US power and improving its efficiency are the main objectives of phacoemulsification technology....

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Related Papers (5)
Torsional ultrasound modality for hard nucleus phacoemulsification cataract extraction

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01 Aug 2008-British Journal of Ophthalmology
M. Zeng, Xing Liu, Yizhi Liu, Y Xia, Lixia Luo, Z Yuan, Y Zeng 
Risk factors for corneal endothelial injury during phacoemulsification

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01 Oct 1996-Journal of Cataract and Refractive Surgery
Ken Hayashi, Hideyuki Hayashi, Fuminori Nakao, Fumihiko Hayashi 
New phacoemulsification technology.

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01 Feb 2005-Current Opinion in Ophthalmology
Richard M. Hoffman, I.H. Fine, Mark Packer
The Lens Opacities Classification System III

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01 Jun 1993-Archives of Ophthalmology
Leo T. Chylack, John K. Wolfe, D.M. Singer, M. C. Leske, Mark A. Bullimore, Ian Bailey, Judith Friend, D. Mccarthy, Suh Yuh Wu 
Endothelial cell loss after phacoemulsification: relation to preoperative and intraoperative parameters

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01 May 2000-Journal of Cataract and Refractive Surgery
Tony Walkow, Norbert Anders, Sonja Klebe