ORIGINAL CLINICAL STUDY
Feasibility of the New Torsional Phacoemulsification Software Phacoemulsification (Ozil IP) in Hard Cataracts Ahmed Mohamed El-Moatassem Kotb, PhD, FRCS Ed*Þ and Amr I. Elawamry, MD, PhD, FRCSGlg* Purpose: To assess the feasibility of using the new torsional intelligent phacoemulsification software (Ozil IP) phacoemulsification in hard cataracts of N3+. Design: A cohort study. Methods: Eighty patients were recruited and randomized into 2 groups, the study group and the control group. Each group consisted of 40 eyes. Routine cataract surgeries were performed using standard torsional software (Ozil) and Ozil IP in hard cataracts of N3+. Main outcome measures included cumulative dissipated energy (CDE), amount of balanced salt solution (BSS) used, and changes in central corneal thickness (CCT). Results: The mean CDE was significantly less in the study group compared with the control group (P = 0.05). The mean time in foot pedal position 3 (FP3) for varying grades of cataract density ranged from 16.3 to 30.2 seconds in the study group and from 19.1 to 39.7 seconds in the control group, which was statistically significant (P = 0.03). The amount of BSS used was 34.19 mL in the study group and 44.05 mL in the control group. On the first postoperative day, CCT was significantly different between the study and the control group (P = 0.005). Conclusions: The 3 parameters (CDE, FP3 and BSS amount) were found to be effective with no significant complications. The new Ozil IP required less CDE and less FP3 time with less postoperative corneal edema, and thus patients had a more rapid visual recovery. Key Words: torsional phacoemulsification, hard cataracts, effective phacotime (EPT), OZIL IP, intelligent phacoemulsification
introduces less energy into the eye, causing minimal damage to corneal endothelial cells. The shearing action of the phacoemulsification tip effectively reduces chatter, which is the movement of lens particles in the anterior chamber, leading to improved efficiency of the procedure. Nevertheless, longitudinal US is more effective in clearing the unsheared particle captured by the tip. Therefore, some surgeons would combine traditional longitudinal US with torsional US in a preset ratio to minimize clogging of the tip, especially in cases of hard cataracts. The application of a fixed ratio of longitudinal US, however, makes the surgery less efficient. A recent development of the torsional phacoemulsification system was the introduction of intelligent phacoemulsification (Ozil IP). It allows a lateral movement of the tip to cut more efficiently with the use of torsional amplitude that decreases repulsion and thermal energy. The software also allows surgeons to use torsional modality only, or to combine longitudinal and torsional US to reduce the risk of occlusion. In the event of a significant vacuum rise, the software automatically switches to apply alternating torsional and longitudinal US to clear the occlusion. On the other hand, the system returns to all torsional with a drop in vacuum levels. The current study aim is to assess the feasibility of using Ozil IP in hard cataracts of N3+.
MATERIALS AND METHODS
(Asia-Pac J Ophthalmol 2013;2: 372Y374)
P
hacoemulsification is the preferred technique for removal of cataracts. The primary mechanism is mechanical cutting of the nucleus through direct contact with an oscillating needle tip.1 In conventional phacoemulsification, needle-tip movement is longitudinal, which can result in decreased cutting efficiency as the back-and-forth movement of the tip pushes the nucleus away from the tip.2Y6 Longitudinal tip movement is associated with reduced followability, defined as the ease by which lens fragment material can be smoothly and progressively aspirated into the tip aperture without being repulsed away.7,8 On the contrary, torsional phacoemulsification, with the Infiniti platform (Alcon Laboratories, Forth Worth, Tex), minimizes chatter of lens material, thus improving the outcomes of the procedure. Another important difference between torsional ultrasound (US) and longitudinal US is that torsional US
From the *Ophthalmology Department, Medicine, Ain Shams University, Cairo, Egypt; and †International Medical Center, Dubai, United Arab Emirates. Received for publication June 12, 2012; accepted January 29, 2013. The authors have no funding or conflicts of interest to declare. Reprints: Ahmed Mohamed El Moatassem, MD, PhD, FRCS, International Medical Center, PO Box 914, Dubai, United Arab of Emirates. E-mail: [email protected]. Copyright * 2013 by Asia Pacific Academy of Ophthalmology ISSN: 2162-0989 DOI: 10.1097/APO.0b013e31828a56f7
372
www.apjo.org
This study comprised consecutive cataract operations performed between August 2010 and August 2011. All patients provided informed consent, and an ethics committee approved the study. Eighty patients (45 men and 35 women) were randomized into one of 2 groups (Table 1). Ozil IP was enabled in Group 1 (40 eyes) with the parameters of longitudinal onset at 95% maximum vacuum, 10-millisecond pulses, and a torsional to longitudinal ratio of 1 to 1 while it was disabled in Group 2, the control group. Routine cataract surgery was performed using the Infiniti phacoemulsification system with Ozil IP by the same surgeon. The operative technique was constant for each case. Coaxial microincision cataract surgery was performed using a 30-degree mini-flared Kelman tip. The technique used for all cases was quick chop (phaco chop)16 (Supplemental Digital Content 1 & 2; http://links.lww.com/APJO/A32 and http://links.lww.com/APJO/A33). Data collected intraoperatively were the cumulative dissipated energy (CDE); the estimated amount of balanced salt solution used and time in foot pedal position 3 (FP3). Patients were examined 1 day postoperatively and data collected included pachymetry, corrected Snellen visual acuity, and central corneal edema grade. Corneal edema was defined as a loss of transparency and an increase in thickness of the cornea, and central corneal edema was graded as follows: 1/2 = trace, minimal corneal clouding and thickening in relation to incision sites; 1 = mild, corneal clouding and thickening affecting less than 25% of the cornea with no Descemet folds and clear iris details; 2 = moderate, corneal clouding and thickening affecting more than 25% of the cornea with few Descemet folds and hazy iris details; 3 = severe,
Asia-Pac J Ophthalmol
&
Volume 2, Number 6, November/December 2013
Copyright © 2013 Asia Pacific Academy of Ophthalmology. Unauthorized reproduction of this article is prohibited.
Asia-Pacific Journal of Ophthalmology
&
Volume 2, Number 6, November/December 2013
Cataract Surgery, Phacoemulsification, Ozil IP
TABLE 1. Comparison Between the Parameters Used in Each Group Parameters Eyes (n)
Vacuum
Aspiration Rate
Power
Bottle Height
Group 1 (study)
400 mm Hg
28Y40 mL /m
110 cm
Group 2 (control)
350 mm Hg
35 mL /m
Phaco power, 0%; torsional amplitude, 15Y100 continuous Ozil IP 90% vacuum, 10 ms Torsional power was set to come on for 35 ms with increasing frequency and power up to an off time of 45 ms
110 cm
TABLE 2. Mean CDE for Varying Grades of Cataract Density CDE, Mean (SD) Eyes (n)
Grade III LCOS, n = 60
Grade IV LCOS, n = 16
Grade V LCOS, n = 4
2.32 (0.84) 2.92 (1.35) 0.01
3.82 (1.57) 5.03 (2.16) 0.01
4.1 (1.62) 6.3 (3.2) 0.005
Group 1 (study), mean (SD) Group 2 (control), mean (SD) P value
The CDE is the mean torsional amplitude phaco time 0.4.
corneal clouding and thickening affecting more than 50% of the cornea with more Descemet folds and no view of iris details. Any operative complications and degree of postoperative iritis were also recorded. Data were analyzed and statistical significance was determined using Student t test. A P value of 0.05 was considered statistically significant.
RESULTS The mean age of the patients was 72 T 4.9 years (range, 57Y78 years), the mean preoperative corneal thickness was 529 T 30 mm, and the mean nuclear sclerosis grade was 3.5 T 0.6. There were no statistically significant differences in age (P = 0.73), sex (P = 0.61) and preoperative CCT (P = 0.20) between the 2 groups. Nuclear density was not significantly different between the study group and the control group (P = 0.44, Mann-Whitney U test). Cataract surgery was uneventful in all cases, with no intraoperative complications in either group. Although the nuclear hardness was of grade 3 or above (in a scale of 5), no eye had any thermal corneal burn. Table 2 shows the cataracts by grade in each group. Sixty eyes (75%) were classified as grade III, 16 eyes (20%) grade IV and 4 eyes (5%) grade V using the Lens Opacities Classification System III (LOCS III). The mean CDE was significantly higher with a higher grade of cataract [P = 0.01, 2-way analysis of variance (ANOVA)] and was significantly less in the study group in comparison with the control group (P G 0.05, 2-way ANOVA; Table 2; Fig. 1). The mean FP3 time for varying grades of cataract density ranged from 16.3 to 30.2 seconds in the study group (Ozil IP) and from 19.1 to 39.7 seconds in the control group (Ozil), which was statistically significant (P = 0.03). The FP3 time was less with the new power-delivery option in 33 (82.5%) of all cataract grades of the study group. The times for grade III nuclei and grade IV nuclei were statistically significantly shorter with the study group than the control group (P G 0.05 and P = 0 .001, respectively) (Fig. 2). * 2013 Asia Pacific Academy of Ophthalmology
The difference in balanced salt solution used by the 2 groups was statistically significant, with a lesser amount being used in the study group than in the control group (34.19 mL vs 44.05 mL; P = 0.009, 2-way ANOVA). The difference between groups increased with the grade of cataract (P = 0.039, 2-way ANOVA). On the first postoperative day, there was a significant difference between CCT in the study and the control group. CCT increased from 529 T 30 mm preoperatively to 532 T 19 mm in the study group and 545 T 26 mm in the control group (P G 0.005, 2-way ANOVA). Forty-six eyes showed no corneal edema while 20 eyes experienced grade 1 striate keratopathy and 14 grade 2 striate keratopathy. All cases of corneal edema resolved by a follow-up visit scheduled for day 30 postoperatively and all corneas were clear on examination. During the postoperative follow-up period, only 10 eyes had postoperative iritis of grade 2+: with 3 eyes in the study group and 7 eyes in the control group. All the cataracts in these
FIGURE 1. Cumulative dissipated energy for each grade in the 2 groups. www.apjo.org
Copyright © 2013 Asia Pacific Academy of Ophthalmology. Unauthorized reproduction of this article is prohibited.
373
Asia-Pacific Journal of Ophthalmology
Kotb and Elawamry
&
Volume 2, Number 6, November/December 2013
4. Walkow T, Anders N, Klebe S. Endothelial cell loss after phacoemulsification: relation to preoperative and intraoperative parameters. J Cataract Refract Surg. 2000;26:727Y732. 5. Liu Y, Zeng M, Liu X, et al. Torsional mode versus conventional ultrasound mode phacoemulsification; randomized comparative clinical study. J Cataract Refract Surg. 2007;33:287Y292. 6. Nixon DR. Preoperative cataract grading by Scheimpflug imaging and effect on operative fluidics and phacoemulsification energy. J Cataract Refract Surg. 2010;36:242Y246. 7. Davison JA. Cumulative tip travel and implied followability of longitudinal and torsional phacoemulsification. J Cataract Refract Surg. 2008;34:986Y990. 8. Coppe AM, Lapucci G. Posterior vitreous detachment and retinal detachment following cataract extraction. Curr Opin Ophthalmol. 2008;19:239Y242.
FIGURE 2 . Foot pedal position 3 times for each grade in the 2 groups.
eyes were classified as LOCS IV and LOCS V. Iritis rapidly improved 1 week after the surgery on topical steroids 4 times per day for 1 week, followed by gradual tapering in the following 2 weeks.
DISCUSSION Studies have recommended the routine use of Intelligent Phaco for denser cataracts. It is beneficial during segment removal, although its use is probably counterproductive during chopping because the longitudinal pulses of phaco may break the required vacuum.17 The overall results in this prospective study suggest that the total time in FP3 and the CDE were lower when using Ozil IP as compared with Ozil in hard cataracts of N3+. The values showed statistical significance. There was also a statistically significant difference in regard to the amount of balanced salt solution used during the operation being less with the use of Ozil IP, which is due to the less time spent in complete occlusion. REFERENCES 1. Packer M, Fishkind WJ, Fine IH, et al. The physics of phaco: a review. J Cataract Refract Surg. 2005;31:424Y431.
9. Fernandez de Castro LE, Dimalanta RC, Solomon KD. Bead-flow pattern: quantitation of fluid movement during torsional and longitudinal phacoemulsification. J Cataract Refract Surg. 2010;36:1018Y1023. 10. Han YK, Miller KM. Heat production: longitudinal versus torsional phacoemulsification. J Cataract Refract Surg. 2009;35:1799Y1805. 11. Rekas M, Montes-Mico R, Krix-Jachym K, et al. Comparison of torsional and longitudinal modes using phacoemulsification parameters. J Cataract Refract Surg. 2009;35:1719Y1724. 12. Bozkurt E, Bayraktar S, Yazgan S, et al. Comparison of conventional and torsional mode (OZil) phacoemulsification: randomized prospective clinical study. Eur J Ophthalmol. 2009;19:984Y989. 13. Reuschel A, Bogatsch H, Barth T, et al. Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification. J Cataract Refract Surg. 2010;36 1855Y1861. 14. Vasavada AR, Raj SM, Patel U, et al. Comparison of torsional and microburst longitudinal phacoemulsification: a prospective, randomized, masked clinical trial. Ophthalmic Surg Lasers Imaging. 2010;41:109Y114. 15. Cionni RJ, Crandall AS, David F. Length and frequency of intraoperative occlusive events with new torsional phacoemulsification software. J Cataract Refract Surg. 2011;37:1785Y1790. 16. Can I, Takmaz T, Cakici F, et al. Comparison of Nagahara phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques. J Cataract Refract Surg. 2004;30:663Y668.
2. Zacharias J. Role of cavitation in the phacoemulsification process. J Cataract Refract Surg. 2008;34:846Y852.
17. Ratnarajan G, Packard R, Ward M. Combined occlusion-triggered longitudinal and torsional phacoemulsification during coaxial microincision cataract surgery: effect on 30-degree mini-flared tip behavior. J Cataract Refract Surg. 2011;37:825Y829.
3. Miyoshi T, Yoshida H. Ultra-high-speed digital video images of vibrations of an ultrasonic tip and phacoemulsification. J Cataract Refract Surg. 2008;34:1024Y1028.
18. Chylack LT Jr, Wolfe JK, Singer MD, et al. Lens Opacities Classification System III (LOCS III). The longitudinal study of lens study group. Arch Ophthalmol. 1993;111:831Y836.
374
www.apjo.org
* 2013 Asia Pacific Academy of Ophthalmology
Copyright © 2013 Asia Pacific Academy of Ophthalmology. Unauthorized reproduction of this article is prohibited.
Feasibility of the New Torsional Phacoemulsification Software Phacoemulsification (Ozil IP) in Hard Cataracts Ahmed Mohamed El-Moatassem Kotb, PhD, FRCS Ed*Þ and Amr I. Elawamry, MD, PhD, FRCSGlg* Purpose: To assess the feasibility of using the new torsional intelligent phacoemulsification software (Ozil IP) phacoemulsification in hard cataracts of N3+. Design: A cohort study. Methods: Eighty patients were recruited and randomized into 2 groups, the study group and the control group. Each group consisted of 40 eyes. Routine cataract surgeries were performed using standard torsional software (Ozil) and Ozil IP in hard cataracts of N3+. Main outcome measures included cumulative dissipated energy (CDE), amount of balanced salt solution (BSS) used, and changes in central corneal thickness (CCT). Results: The mean CDE was significantly less in the study group compared with the control group (P = 0.05). The mean time in foot pedal position 3 (FP3) for varying grades of cataract density ranged from 16.3 to 30.2 seconds in the study group and from 19.1 to 39.7 seconds in the control group, which was statistically significant (P = 0.03). The amount of BSS used was 34.19 mL in the study group and 44.05 mL in the control group. On the first postoperative day, CCT was significantly different between the study and the control group (P = 0.005). Conclusions: The 3 parameters (CDE, FP3 and BSS amount) were found to be effective with no significant complications. The new Ozil IP required less CDE and less FP3 time with less postoperative corneal edema, and thus patients had a more rapid visual recovery. Key Words: torsional phacoemulsification, hard cataracts, effective phacotime (EPT), OZIL IP, intelligent phacoemulsification
introduces less energy into the eye, causing minimal damage to corneal endothelial cells. The shearing action of the phacoemulsification tip effectively reduces chatter, which is the movement of lens particles in the anterior chamber, leading to improved efficiency of the procedure. Nevertheless, longitudinal US is more effective in clearing the unsheared particle captured by the tip. Therefore, some surgeons would combine traditional longitudinal US with torsional US in a preset ratio to minimize clogging of the tip, especially in cases of hard cataracts. The application of a fixed ratio of longitudinal US, however, makes the surgery less efficient. A recent development of the torsional phacoemulsification system was the introduction of intelligent phacoemulsification (Ozil IP). It allows a lateral movement of the tip to cut more efficiently with the use of torsional amplitude that decreases repulsion and thermal energy. The software also allows surgeons to use torsional modality only, or to combine longitudinal and torsional US to reduce the risk of occlusion. In the event of a significant vacuum rise, the software automatically switches to apply alternating torsional and longitudinal US to clear the occlusion. On the other hand, the system returns to all torsional with a drop in vacuum levels. The current study aim is to assess the feasibility of using Ozil IP in hard cataracts of N3+.
MATERIALS AND METHODS
(Asia-Pac J Ophthalmol 2013;2: 372Y374)
P
hacoemulsification is the preferred technique for removal of cataracts. The primary mechanism is mechanical cutting of the nucleus through direct contact with an oscillating needle tip.1 In conventional phacoemulsification, needle-tip movement is longitudinal, which can result in decreased cutting efficiency as the back-and-forth movement of the tip pushes the nucleus away from the tip.2Y6 Longitudinal tip movement is associated with reduced followability, defined as the ease by which lens fragment material can be smoothly and progressively aspirated into the tip aperture without being repulsed away.7,8 On the contrary, torsional phacoemulsification, with the Infiniti platform (Alcon Laboratories, Forth Worth, Tex), minimizes chatter of lens material, thus improving the outcomes of the procedure. Another important difference between torsional ultrasound (US) and longitudinal US is that torsional US
From the *Ophthalmology Department, Medicine, Ain Shams University, Cairo, Egypt; and †International Medical Center, Dubai, United Arab Emirates. Received for publication June 12, 2012; accepted January 29, 2013. The authors have no funding or conflicts of interest to declare. Reprints: Ahmed Mohamed El Moatassem, MD, PhD, FRCS, International Medical Center, PO Box 914, Dubai, United Arab of Emirates. E-mail: [email protected]. Copyright * 2013 by Asia Pacific Academy of Ophthalmology ISSN: 2162-0989 DOI: 10.1097/APO.0b013e31828a56f7
372
www.apjo.org
This study comprised consecutive cataract operations performed between August 2010 and August 2011. All patients provided informed consent, and an ethics committee approved the study. Eighty patients (45 men and 35 women) were randomized into one of 2 groups (Table 1). Ozil IP was enabled in Group 1 (40 eyes) with the parameters of longitudinal onset at 95% maximum vacuum, 10-millisecond pulses, and a torsional to longitudinal ratio of 1 to 1 while it was disabled in Group 2, the control group. Routine cataract surgery was performed using the Infiniti phacoemulsification system with Ozil IP by the same surgeon. The operative technique was constant for each case. Coaxial microincision cataract surgery was performed using a 30-degree mini-flared Kelman tip. The technique used for all cases was quick chop (phaco chop)16 (Supplemental Digital Content 1 & 2; http://links.lww.com/APJO/A32 and http://links.lww.com/APJO/A33). Data collected intraoperatively were the cumulative dissipated energy (CDE); the estimated amount of balanced salt solution used and time in foot pedal position 3 (FP3). Patients were examined 1 day postoperatively and data collected included pachymetry, corrected Snellen visual acuity, and central corneal edema grade. Corneal edema was defined as a loss of transparency and an increase in thickness of the cornea, and central corneal edema was graded as follows: 1/2 = trace, minimal corneal clouding and thickening in relation to incision sites; 1 = mild, corneal clouding and thickening affecting less than 25% of the cornea with no Descemet folds and clear iris details; 2 = moderate, corneal clouding and thickening affecting more than 25% of the cornea with few Descemet folds and hazy iris details; 3 = severe,
Asia-Pac J Ophthalmol
&
Volume 2, Number 6, November/December 2013
Copyright © 2013 Asia Pacific Academy of Ophthalmology. Unauthorized reproduction of this article is prohibited.
Asia-Pacific Journal of Ophthalmology
&
Volume 2, Number 6, November/December 2013
Cataract Surgery, Phacoemulsification, Ozil IP
TABLE 1. Comparison Between the Parameters Used in Each Group Parameters Eyes (n)
Vacuum
Aspiration Rate
Power
Bottle Height
Group 1 (study)
400 mm Hg
28Y40 mL /m
110 cm
Group 2 (control)
350 mm Hg
35 mL /m
Phaco power, 0%; torsional amplitude, 15Y100 continuous Ozil IP 90% vacuum, 10 ms Torsional power was set to come on for 35 ms with increasing frequency and power up to an off time of 45 ms
110 cm
TABLE 2. Mean CDE for Varying Grades of Cataract Density CDE, Mean (SD) Eyes (n)
Grade III LCOS, n = 60
Grade IV LCOS, n = 16
Grade V LCOS, n = 4
2.32 (0.84) 2.92 (1.35) 0.01
3.82 (1.57) 5.03 (2.16) 0.01
4.1 (1.62) 6.3 (3.2) 0.005
Group 1 (study), mean (SD) Group 2 (control), mean (SD) P value
The CDE is the mean torsional amplitude phaco time 0.4.
corneal clouding and thickening affecting more than 50% of the cornea with more Descemet folds and no view of iris details. Any operative complications and degree of postoperative iritis were also recorded. Data were analyzed and statistical significance was determined using Student t test. A P value of 0.05 was considered statistically significant.
RESULTS The mean age of the patients was 72 T 4.9 years (range, 57Y78 years), the mean preoperative corneal thickness was 529 T 30 mm, and the mean nuclear sclerosis grade was 3.5 T 0.6. There were no statistically significant differences in age (P = 0.73), sex (P = 0.61) and preoperative CCT (P = 0.20) between the 2 groups. Nuclear density was not significantly different between the study group and the control group (P = 0.44, Mann-Whitney U test). Cataract surgery was uneventful in all cases, with no intraoperative complications in either group. Although the nuclear hardness was of grade 3 or above (in a scale of 5), no eye had any thermal corneal burn. Table 2 shows the cataracts by grade in each group. Sixty eyes (75%) were classified as grade III, 16 eyes (20%) grade IV and 4 eyes (5%) grade V using the Lens Opacities Classification System III (LOCS III). The mean CDE was significantly higher with a higher grade of cataract [P = 0.01, 2-way analysis of variance (ANOVA)] and was significantly less in the study group in comparison with the control group (P G 0.05, 2-way ANOVA; Table 2; Fig. 1). The mean FP3 time for varying grades of cataract density ranged from 16.3 to 30.2 seconds in the study group (Ozil IP) and from 19.1 to 39.7 seconds in the control group (Ozil), which was statistically significant (P = 0.03). The FP3 time was less with the new power-delivery option in 33 (82.5%) of all cataract grades of the study group. The times for grade III nuclei and grade IV nuclei were statistically significantly shorter with the study group than the control group (P G 0.05 and P = 0 .001, respectively) (Fig. 2). * 2013 Asia Pacific Academy of Ophthalmology
The difference in balanced salt solution used by the 2 groups was statistically significant, with a lesser amount being used in the study group than in the control group (34.19 mL vs 44.05 mL; P = 0.009, 2-way ANOVA). The difference between groups increased with the grade of cataract (P = 0.039, 2-way ANOVA). On the first postoperative day, there was a significant difference between CCT in the study and the control group. CCT increased from 529 T 30 mm preoperatively to 532 T 19 mm in the study group and 545 T 26 mm in the control group (P G 0.005, 2-way ANOVA). Forty-six eyes showed no corneal edema while 20 eyes experienced grade 1 striate keratopathy and 14 grade 2 striate keratopathy. All cases of corneal edema resolved by a follow-up visit scheduled for day 30 postoperatively and all corneas were clear on examination. During the postoperative follow-up period, only 10 eyes had postoperative iritis of grade 2+: with 3 eyes in the study group and 7 eyes in the control group. All the cataracts in these
FIGURE 1. Cumulative dissipated energy for each grade in the 2 groups. www.apjo.org
Copyright © 2013 Asia Pacific Academy of Ophthalmology. Unauthorized reproduction of this article is prohibited.
373
Asia-Pacific Journal of Ophthalmology
Kotb and Elawamry
&
Volume 2, Number 6, November/December 2013
4. Walkow T, Anders N, Klebe S. Endothelial cell loss after phacoemulsification: relation to preoperative and intraoperative parameters. J Cataract Refract Surg. 2000;26:727Y732. 5. Liu Y, Zeng M, Liu X, et al. Torsional mode versus conventional ultrasound mode phacoemulsification; randomized comparative clinical study. J Cataract Refract Surg. 2007;33:287Y292. 6. Nixon DR. Preoperative cataract grading by Scheimpflug imaging and effect on operative fluidics and phacoemulsification energy. J Cataract Refract Surg. 2010;36:242Y246. 7. Davison JA. Cumulative tip travel and implied followability of longitudinal and torsional phacoemulsification. J Cataract Refract Surg. 2008;34:986Y990. 8. Coppe AM, Lapucci G. Posterior vitreous detachment and retinal detachment following cataract extraction. Curr Opin Ophthalmol. 2008;19:239Y242.
FIGURE 2 . Foot pedal position 3 times for each grade in the 2 groups.
eyes were classified as LOCS IV and LOCS V. Iritis rapidly improved 1 week after the surgery on topical steroids 4 times per day for 1 week, followed by gradual tapering in the following 2 weeks.
DISCUSSION Studies have recommended the routine use of Intelligent Phaco for denser cataracts. It is beneficial during segment removal, although its use is probably counterproductive during chopping because the longitudinal pulses of phaco may break the required vacuum.17 The overall results in this prospective study suggest that the total time in FP3 and the CDE were lower when using Ozil IP as compared with Ozil in hard cataracts of N3+. The values showed statistical significance. There was also a statistically significant difference in regard to the amount of balanced salt solution used during the operation being less with the use of Ozil IP, which is due to the less time spent in complete occlusion. REFERENCES 1. Packer M, Fishkind WJ, Fine IH, et al. The physics of phaco: a review. J Cataract Refract Surg. 2005;31:424Y431.
9. Fernandez de Castro LE, Dimalanta RC, Solomon KD. Bead-flow pattern: quantitation of fluid movement during torsional and longitudinal phacoemulsification. J Cataract Refract Surg. 2010;36:1018Y1023. 10. Han YK, Miller KM. Heat production: longitudinal versus torsional phacoemulsification. J Cataract Refract Surg. 2009;35:1799Y1805. 11. Rekas M, Montes-Mico R, Krix-Jachym K, et al. Comparison of torsional and longitudinal modes using phacoemulsification parameters. J Cataract Refract Surg. 2009;35:1719Y1724. 12. Bozkurt E, Bayraktar S, Yazgan S, et al. Comparison of conventional and torsional mode (OZil) phacoemulsification: randomized prospective clinical study. Eur J Ophthalmol. 2009;19:984Y989. 13. Reuschel A, Bogatsch H, Barth T, et al. Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification. J Cataract Refract Surg. 2010;36 1855Y1861. 14. Vasavada AR, Raj SM, Patel U, et al. Comparison of torsional and microburst longitudinal phacoemulsification: a prospective, randomized, masked clinical trial. Ophthalmic Surg Lasers Imaging. 2010;41:109Y114. 15. Cionni RJ, Crandall AS, David F. Length and frequency of intraoperative occlusive events with new torsional phacoemulsification software. J Cataract Refract Surg. 2011;37:1785Y1790. 16. Can I, Takmaz T, Cakici F, et al. Comparison of Nagahara phaco-chop and stop-and-chop phacoemulsification nucleotomy techniques. J Cataract Refract Surg. 2004;30:663Y668.
2. Zacharias J. Role of cavitation in the phacoemulsification process. J Cataract Refract Surg. 2008;34:846Y852.
17. Ratnarajan G, Packard R, Ward M. Combined occlusion-triggered longitudinal and torsional phacoemulsification during coaxial microincision cataract surgery: effect on 30-degree mini-flared tip behavior. J Cataract Refract Surg. 2011;37:825Y829.
3. Miyoshi T, Yoshida H. Ultra-high-speed digital video images of vibrations of an ultrasonic tip and phacoemulsification. J Cataract Refract Surg. 2008;34:1024Y1028.
18. Chylack LT Jr, Wolfe JK, Singer MD, et al. Lens Opacities Classification System III (LOCS III). The longitudinal study of lens study group. Arch Ophthalmol. 1993;111:831Y836.
374
www.apjo.org
* 2013 Asia Pacific Academy of Ophthalmology
Copyright © 2013 Asia Pacific Academy of Ophthalmology. Unauthorized reproduction of this article is prohibited.
